Initial Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

LLM Generation

Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

Output

Here's a possible implementation of the function `rref` in C: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

typedef uint16_t matrix_t;
typedef uint32_t set_t;

// Returns the number of elements in a set.
int set_size(set_t *set) {
  int count = 0;
  for (int i = 0; i < 32; i++) {
    if (set[i / 32] & (1 << (i % 32))) {
      count++;
    }
  }
  return count;
}

// Swaps two rows in a matrix.
void swap_rows(matrix_t **matrix, int row1, int row2, int cols) {
  matrix_t *tmp = matrix[row1];
  matrix[row1] = matrix[row2];
  matrix[row2] = tmp;
}

// Returns the index of the first non-zero element in a row, starting from col.
int find_pivot(matrix_t **matrix, int row, int col, int cols) {
  for (int i = col; i < cols; i++) {
    if (matrix[row][i] != 0) {
      return i;
    }
  }
  return -1;
}

// Returns true if all elements in a row are zero.
bool is_zero_row(matrix_t **matrix, int row, int cols) {
  for (int i = 0; i < cols; i++) {
    if (matrix[row][i] != 0) {
      return false;
    }
  }
  return true;
}

// Computes the reduced row echelon form (RREF) of a matrix and returns an array of sets
// indicating which rows are used to eliminate zeros in other rows. The input matrix is
// modified in place.
int **rref(matrix_t **matrix, int rows, int cols, int graphlen) {
  const int PH = 16;
  int *used_for_row = calloc(rows, sizeof(int));
  for (int i = 0; i < rows; i++) {
    used_for_row[i] = 1 << i;
  }
  int extra = 0;
  int col = 0;
  int pivots[rows];
  int num_pivots = 0;
  while (col + extra < cols - 1 && col < rows) {
    int pivot_col = find_pivot(matrix, col, col + extra, cols);
    if (pivot_col == -1) {
      if (is_zero_row(matrix, col, cols)) {
        extra++;
        continue;
      }
      int other = find_pivot(matrix, 0, col + extra, cols) + col + extra;
      if (other <= col) {
        extra++;
        continue;
      }
      swap_rows(matrix, col, other / cols, cols);
      used_for_row[col] |= used_for_row[other / cols];
    }
    pivots[num_pivots++] = col + extra;
    matrix_t pivot = matrix[col][col + extra];
    if (col + extra < graphlen) {
      if (pivot != 1 && pivot != PH - 1) {
        matrix[col][col + extra] = pivot == 0 ? 1 : (pivot > 0 ? PH - pivot : -pivot);
      }
    } else {
      if (pivot != 2 && pivot != PH - 2) {
        matrix[col][col + extra] = pivot == 0 ? 2 : (pivot > 0 ? PH - pivot : -pivot) / 2;
      }
    }
    matrix[col][col + extra] %= PH;
    for (int i = 0; i < rows; i++) {
      if (i == col) {
        continue;
      }
      matrix_t factor = matrix[i][col + extra];
      if (factor != 0) {
        used_for_row[i] |= used_for_row[col];
        if (col < graphlen) {
          for (int j = 0; j < cols; j++) {
            matrix[i][j] = (matrix[i][j] - matrix[col][j] * factor + PH) % PH;
          }
        } else {
          while (matrix[i][col + extra] != 0) {
            for (int j = 0; j < cols; j++) {
              matrix[i][j] = (matrix[i][j] - matrix[col][j] + PH) % PH;
            }
          }
        }
      }
    }
    col++;
  }
  for (int i = 0; i < rows; i++) {
    used_for_row[i] = set_size(used_for_row + (i >> 5)) - __builtin_popcount((used_for_row[i] >> (i % 32)) & ((1 << (i % 32 + 1)) - 1));
  }
  int **result = malloc(rows * sizeof(int *));
  for (int i = 0; i < rows; i++) {
    result[i] = malloc(used_for_row[i] * sizeof(int));
    int *set = result[i];
    int j = 0;
    for (int k = 0; k < rows; k++) {
      if ((used_for_row[i] >> k) & 1) {
        set[j++] = k;
      }
    }
  }
  free(used_for_row);
  return result;
}
Note that this implementation uses a bitset to represent the sets of used rows, which requires some additional logic to compute the size of a set and to convert it to an array of integers. Also note that this implementation assumes that the input matrix is a 2D array of `matrix_t` values, where `matrix_t` is a 16-bit unsigned integer type. If your matrix uses a different data type, you may need to modify the function accordingly.

Extract Code

I extracted the following code from that output: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

typedef uint16_t matrix_t;
typedef uint32_t set_t;

// Returns the number of elements in a set.
int set_size(set_t *set) {
  int count = 0;
  for (int i = 0; i < 32; i++) {
    if (set[i / 32] & (1 << (i % 32))) {
      count++;
    }
  }
  return count;
}

// Swaps two rows in a matrix.
void swap_rows(matrix_t **matrix, int row1, int row2, int cols) {
  matrix_t *tmp = matrix[row1];
  matrix[row1] = matrix[row2];
  matrix[row2] = tmp;
}

// Returns the index of the first non-zero element in a row, starting from col.
int find_pivot(matrix_t **matrix, int row, int col, int cols) {
  for (int i = col; i < cols; i++) {
    if (matrix[row][i] != 0) {
      return i;
    }
  }
  return -1;
}

// Returns true if all elements in a row are zero.
bool is_zero_row(matrix_t **matrix, int row, int cols) {
  for (int i = 0; i < cols; i++) {
    if (matrix[row][i] != 0) {
      return false;
    }
  }
  return true;
}

// Computes the reduced row echelon form (RREF) of a matrix and returns an array of sets
// indicating which rows are used to eliminate zeros in other rows. The input matrix is
// modified in place.
int **rref(matrix_t **matrix, int rows, int cols, int graphlen) {
  const int PH = 16;
  int *used_for_row = calloc(rows, sizeof(int));
  for (int i = 0; i < rows; i++) {
    used_for_row[i] = 1 << i;
  }
  int extra = 0;
  int col = 0;
  int pivots[rows];
  int num_pivots = 0;
  while (col + extra < cols - 1 && col < rows) {
    int pivot_col = find_pivot(matrix, col, col + extra, cols);
    if (pivot_col == -1) {
      if (is_zero_row(matrix, col, cols)) {
        extra++;
        continue;
      }
      int other = find_pivot(matrix, 0, col + extra, cols) + col + extra;
      if (other <= col) {
        extra++;
        continue;
      }
      swap_rows(matrix, col, other / cols, cols);
      used_for_row[col] |= used_for_row[other / cols];
    }
    pivots[num_pivots++] = col + extra;
    matrix_t pivot = matrix[col][col + extra];
    if (col + extra < graphlen) {
      if (pivot != 1 && pivot != PH - 1) {
        matrix[col][col + extra] = pivot == 0 ? 1 : (pivot > 0 ? PH - pivot : -pivot);
      }
    } else {
      if (pivot != 2 && pivot != PH - 2) {
        matrix[col][col + extra] = pivot == 0 ? 2 : (pivot > 0 ? PH - pivot : -pivot) / 2;
      }
    }
    matrix[col][col + extra] %= PH;
    for (int i = 0; i < rows; i++) {
      if (i == col) {
        continue;
      }
      matrix_t factor = matrix[i][col + extra];
      if (factor != 0) {
        used_for_row[i] |= used_for_row[col];
        if (col < graphlen) {
          for (int j = 0; j < cols; j++) {
            matrix[i][j] = (matrix[i][j] - matrix[col][j] * factor + PH) % PH;
          }
        } else {
          while (matrix[i][col + extra] != 0) {
            for (int j = 0; j < cols; j++) {
              matrix[i][j] = (matrix[i][j] - matrix[col][j] + PH) % PH;
            }
          }
        }
      }
    }
    col++;
  }
  for (int i = 0; i < rows; i++) {
    used_for_row[i] = set_size(used_for_row + (i >> 5)) - __builtin_popcount((used_for_row[i] >> (i % 32)) & ((1 << (i % 32 + 1)) - 1));
  }
  int **result = malloc(rows * sizeof(int *));
  for (int i = 0; i < rows; i++) {
    result[i] = malloc(used_for_row[i] * sizeof(int));
    int *set = result[i];
    int j = 0;
    for (int k = 0; k < rows; k++) {
      if ((used_for_row[i] >> k) & 1) {
        set[j++] = k;
      }
    }
  }
  free(used_for_row);
  return result;
}

Run Code Interpreter

Running the following program: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

typedef uint16_t matrix_t;
typedef uint32_t set_t;

// Returns the number of elements in a set.
int set_size(set_t *set) {
  int count = 0;
  for (int i = 0; i < 32; i++) {
    if (set[i / 32] & (1 << (i % 32))) {
      count++;
    }
  }
  return count;
}

// Swaps two rows in a matrix.
void swap_rows(matrix_t **matrix, int row1, int row2, int cols) {
  matrix_t *tmp = matrix[row1];
  matrix[row1] = matrix[row2];
  matrix[row2] = tmp;
}

// Returns the index of the first non-zero element in a row, starting from col.
int find_pivot(matrix_t **matrix, int row, int col, int cols) {
  for (int i = col; i < cols; i++) {
    if (matrix[row][i] != 0) {
      return i;
    }
  }
  return -1;
}

// Returns true if all elements in a row are zero.
bool is_zero_row(matrix_t **matrix, int row, int cols) {
  for (int i = 0; i < cols; i++) {
    if (matrix[row][i] != 0) {
      return false;
    }
  }
  return true;
}

// Computes the reduced row echelon form (RREF) of a matrix and returns an array of sets
// indicating which rows are used to eliminate zeros in other rows. The input matrix is
// modified in place.
int **rref(matrix_t **matrix, int rows, int cols, int graphlen) {
  const int PH = 16;
  int *used_for_row = calloc(rows, sizeof(int));
  for (int i = 0; i < rows; i++) {
    used_for_row[i] = 1 << i;
  }
  int extra = 0;
  int col = 0;
  int pivots[rows];
  int num_pivots = 0;
  while (col + extra < cols - 1 && col < rows) {
    int pivot_col = find_pivot(matrix, col, col + extra, cols);
    if (pivot_col == -1) {
      if (is_zero_row(matrix, col, cols)) {
        extra++;
        continue;
      }
      int other = find_pivot(matrix, 0, col + extra, cols) + col + extra;
      if (other <= col) {
        extra++;
        continue;
      }
      swap_rows(matrix, col, other / cols, cols);
      used_for_row[col] |= used_for_row[other / cols];
    }
    pivots[num_pivots++] = col + extra;
    matrix_t pivot = matrix[col][col + extra];
    if (col + extra < graphlen) {
      if (pivot != 1 && pivot != PH - 1) {
        matrix[col][col + extra] = pivot == 0 ? 1 : (pivot > 0 ? PH - pivot : -pivot);
      }
    } else {
      if (pivot != 2 && pivot != PH - 2) {
        matrix[col][col + extra] = pivot == 0 ? 2 : (pivot > 0 ? PH - pivot : -pivot) / 2;
      }
    }
    matrix[col][col + extra] %= PH;
    for (int i = 0; i < rows; i++) {
      if (i == col) {
        continue;
      }
      matrix_t factor = matrix[i][col + extra];
      if (factor != 0) {
        used_for_row[i] |= used_for_row[col];
        if (col < graphlen) {
          for (int j = 0; j < cols; j++) {
            matrix[i][j] = (matrix[i][j] - matrix[col][j] * factor + PH) % PH;
          }
        } else {
          while (matrix[i][col + extra] != 0) {
            for (int j = 0; j < cols; j++) {
              matrix[i][j] = (matrix[i][j] - matrix[col][j] + PH) % PH;
            }
          }
        }
      }
    }
    col++;
  }
  for (int i = 0; i < rows; i++) {
    used_for_row[i] = set_size(used_for_row + (i >> 5)) - __builtin_popcount((used_for_row[i] >> (i % 32)) & ((1 << (i % 32 + 1)) - 1));
  }
  int **result = malloc(rows * sizeof(int *));
  for (int i = 0; i < rows; i++) {
    result[i] = malloc(used_for_row[i] * sizeof(int));
    int *set = result[i];
    int j = 0;
    for (int k = 0; k < rows; k++) {
      if ((used_for_row[i] >> k) & 1) {
        set[j++] = k;
      }
    }
  }
  free(used_for_row);
  return result;
}



#include<stdio.h>
#include<stdlib.h>
int main() {

int arr0[] = {1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr1[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr2[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr3[] = {0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr4[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr5[] = {0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr6[] = {0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0};
int arr7[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, -30};
int arr8[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr9[] = {0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, -20};
int arr10[] = {1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr11[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr12[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr13[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -14};
int arr14[] = {0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr15[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, -30};
int arr16[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr17[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr18[] = {0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr19[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr20[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr21[] = {0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr22[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, -20};
int arr23[] = {0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr24[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr25[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr26[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr27[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr28[] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr29[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr30[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr31[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr32[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, -10};
int arr33[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr34[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr35[] = {0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -9};
int arr36[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, -20};
int arr37[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, -40};
int arr38[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int* arr[] = {arr0, arr1, arr2, arr3, arr4, arr5, arr6, arr7, arr8, arr9, arr10, arr11, arr12, arr13, arr14, arr15, arr16, arr17, arr18, arr19, arr20, arr21, arr22, arr23, arr24, arr25, arr26, arr27, arr28, arr29, arr30, arr31, arr32, arr33, arr34, arr35, arr36, arr37, arr38};
int** got = rref(arr, 39, 49, 37);


int answer = got[3][0]+got[3][1]+got[3][2]+got[3][3]+got[3][4]+got[3][5]+got[3][6];
int expected = 146;
if (answer != expected) {
    printf("Wrong answer; got %d instead of %d.\n", answer, expected);
    exit(1);
}
printf("All tests passed\n");
}
And got the output: main.c: In function 'main': main.c:173:18: warning: passing argument 1 of 'rref' from incompatible pointer type [-Wincompatible-pointer-types] 173 | int** got = rref(arr, 39, 49, 37); | ^~~ | | | int ** main.c:50:23: note: expected 'matrix_t **' {aka 'short unsigned int **'} but argument is of type 'int **' 50 | int **rref(matrix_t **matrix, int rows, int cols, int graphlen) { | ~~~~~~~~~~~^~~~~~ main.sh: line 2: 16 Segmentation fault (core dumped) ./a.out

Substring Evaluation

Testing if the previous output contains the string All tests passed: False

Initial Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

LLM Generation

Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

Output

Here's a possible implementation of the rref function in C: 

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#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>

#define PH 16

// Function to swap two rows of a matrix
void swap_rows(int** matrix, int i, int j, int cols) {
    int tmp[cols];
    for (int k = 0; k < cols; k++) {
        tmp[k] = matrix[i][k];
        matrix[i][k] = matrix[j][k];
        matrix[j][k] = tmp[k];
    }
}

// Function to perform Gaussian elimination on a matrix
void gaussian_elimination(int** matrix, int* used_for_row, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    int pivots[rows];
    int num_pivots = 0;
    bool row_is_zero[rows];
    for (int i = 0; i < rows; i++) {
        row_is_zero[i] = true;
        for (int j = col; j < cols; j++) {
            if (matrix[i][j] != 0) {
                row_is_zero[i] = false;
                break;
            }
        }
    }
    while (col + extra < cols - 1 && col < rows) {
        int i = 0;
        for (i = 0; i < rows && row_is_zero[i]; i++);
        if (i == rows) {
            extra++;
            continue;
        }
        if (matrix[i][col + extra] == 0) {
            int j = i + 1;
            for (; j < rows && matrix[j][col + extra] == 0; j++);
            if (j == rows) {
                extra++;
                continue;
            }
            swap_rows(matrix, i, j, cols);
            used_for_row[i] = used_for_row[j];
        }
        pivots[num_pivots++] = col + extra;
        int pivot = matrix[i][col + extra];
        if (col + extra < graphlen) {
            if (abs(pivot) != 1 && abs(pivot) != PH - 1) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
        } else {
            if (abs(pivot) != 2 && abs(pivot) != PH - 2) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
            pivot /= 2;
        }
        matrix[i][col + extra] = pivot;
        for (int j = 0; j < rows; j++) {
            if (j == i) continue;
            int factor = matrix[j][col + extra];
            if (col + extra < graphlen) {
                matrix[j][col + extra] = 0;
                for (int k = col + extra + 1; k < cols; k++) {
                    matrix[j][k] -= matrix[i][k] * factor;
                }
            } else {
                while (matrix[j][col + extra] != 0) {
                    matrix[j] = (matrix[j] - matrix[i]) % PH;
                }
            }
            used_for_row[j] |= used_for_row[i];
        }
        col++;
    }
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] %= PH;
        }
    }
}

// Function to convert a set of integers to an array of integers in C
int** set_to_array(int* set, int size) {
    int* array = malloc(size * sizeof(int));
    int* current = array;
    for (int i = 0; i < size; i++) {
        if (set[i] / 32 != (*current) / 32) {
            (*current)++;
        }
        int index = set[i] % 32;
        array[*current] |= 1 << index;
    }
    int* length = malloc(sizeof(int));
    *length = current - array + 1;
    int** result = malloc(2 * sizeof(int*));
    result[0] = array;
    result[1] = length;
    return result;
}

// Function to perform reduced row echelon form on a matrix
int** rref(int** matrix, int rows, int cols, int graphlen) {
    int** used_for_row = calloc(rows, sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = calloc(rows, sizeof(int));
        used_for_row[i][i / 32] |= 1 << (i % 32);
    }
    gaussian_elimination(matrix, used_for_row, rows, cols, graphlen);
    int** result = set_to_array(used_for_row[0], rows);
    for (int i = 1; i < rows; i++) {
        int* temp = set_to_array(used_for_row[i], rows);
        for (int j = 0; j < *(result[1]); j++) {
            result[0][j] |= temp[j];
        }
        free(temp[0]);
        free(temp[1]);
        free(temp);
    }
    for (int i = 0; i < rows; i++) {
        free(used_for_row[i]);
    }
    free(used_for_row);
    return result;
}
This implementation assumes that the input matrix is stored as a 2D array of integers, where each integer represents a number modulo PH. It uses a set of integers to keep track of which rows are used in the Gaussian elimination process, and converts this set to an array of integers before returning it. Note that this implementation does not handle the case where the input matrix is not in the correct format. You may need to add additional error checking to handle this case. Also note that this implementation uses dynamic memory allocation to create the used\_for\_row array and the result array. Be sure to free this memory when you are finished using it to avoid memory leaks.

Extract Code

I extracted the following code from that output: 

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#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>

#define PH 16

// Function to swap two rows of a matrix
void swap_rows(int** matrix, int i, int j, int cols) {
    int tmp[cols];
    for (int k = 0; k < cols; k++) {
        tmp[k] = matrix[i][k];
        matrix[i][k] = matrix[j][k];
        matrix[j][k] = tmp[k];
    }
}

// Function to perform Gaussian elimination on a matrix
void gaussian_elimination(int** matrix, int* used_for_row, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    int pivots[rows];
    int num_pivots = 0;
    bool row_is_zero[rows];
    for (int i = 0; i < rows; i++) {
        row_is_zero[i] = true;
        for (int j = col; j < cols; j++) {
            if (matrix[i][j] != 0) {
                row_is_zero[i] = false;
                break;
            }
        }
    }
    while (col + extra < cols - 1 && col < rows) {
        int i = 0;
        for (i = 0; i < rows && row_is_zero[i]; i++);
        if (i == rows) {
            extra++;
            continue;
        }
        if (matrix[i][col + extra] == 0) {
            int j = i + 1;
            for (; j < rows && matrix[j][col + extra] == 0; j++);
            if (j == rows) {
                extra++;
                continue;
            }
            swap_rows(matrix, i, j, cols);
            used_for_row[i] = used_for_row[j];
        }
        pivots[num_pivots++] = col + extra;
        int pivot = matrix[i][col + extra];
        if (col + extra < graphlen) {
            if (abs(pivot) != 1 && abs(pivot) != PH - 1) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
        } else {
            if (abs(pivot) != 2 && abs(pivot) != PH - 2) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
            pivot /= 2;
        }
        matrix[i][col + extra] = pivot;
        for (int j = 0; j < rows; j++) {
            if (j == i) continue;
            int factor = matrix[j][col + extra];
            if (col + extra < graphlen) {
                matrix[j][col + extra] = 0;
                for (int k = col + extra + 1; k < cols; k++) {
                    matrix[j][k] -= matrix[i][k] * factor;
                }
            } else {
                while (matrix[j][col + extra] != 0) {
                    matrix[j] = (matrix[j] - matrix[i]) % PH;
                }
            }
            used_for_row[j] |= used_for_row[i];
        }
        col++;
    }
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] %= PH;
        }
    }
}

// Function to convert a set of integers to an array of integers in C
int** set_to_array(int* set, int size) {
    int* array = malloc(size * sizeof(int));
    int* current = array;
    for (int i = 0; i < size; i++) {
        if (set[i] / 32 != (*current) / 32) {
            (*current)++;
        }
        int index = set[i] % 32;
        array[*current] |= 1 << index;
    }
    int* length = malloc(sizeof(int));
    *length = current - array + 1;
    int** result = malloc(2 * sizeof(int*));
    result[0] = array;
    result[1] = length;
    return result;
}

// Function to perform reduced row echelon form on a matrix
int** rref(int** matrix, int rows, int cols, int graphlen) {
    int** used_for_row = calloc(rows, sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = calloc(rows, sizeof(int));
        used_for_row[i][i / 32] |= 1 << (i % 32);
    }
    gaussian_elimination(matrix, used_for_row, rows, cols, graphlen);
    int** result = set_to_array(used_for_row[0], rows);
    for (int i = 1; i < rows; i++) {
        int* temp = set_to_array(used_for_row[i], rows);
        for (int j = 0; j < *(result[1]); j++) {
            result[0][j] |= temp[j];
        }
        free(temp[0]);
        free(temp[1]);
        free(temp);
    }
    for (int i = 0; i < rows; i++) {
        free(used_for_row[i]);
    }
    free(used_for_row);
    return result;
}

Run Code Interpreter

Running the following program: 

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#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>

#define PH 16

// Function to swap two rows of a matrix
void swap_rows(int** matrix, int i, int j, int cols) {
    int tmp[cols];
    for (int k = 0; k < cols; k++) {
        tmp[k] = matrix[i][k];
        matrix[i][k] = matrix[j][k];
        matrix[j][k] = tmp[k];
    }
}

// Function to perform Gaussian elimination on a matrix
void gaussian_elimination(int** matrix, int* used_for_row, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    int pivots[rows];
    int num_pivots = 0;
    bool row_is_zero[rows];
    for (int i = 0; i < rows; i++) {
        row_is_zero[i] = true;
        for (int j = col; j < cols; j++) {
            if (matrix[i][j] != 0) {
                row_is_zero[i] = false;
                break;
            }
        }
    }
    while (col + extra < cols - 1 && col < rows) {
        int i = 0;
        for (i = 0; i < rows && row_is_zero[i]; i++);
        if (i == rows) {
            extra++;
            continue;
        }
        if (matrix[i][col + extra] == 0) {
            int j = i + 1;
            for (; j < rows && matrix[j][col + extra] == 0; j++);
            if (j == rows) {
                extra++;
                continue;
            }
            swap_rows(matrix, i, j, cols);
            used_for_row[i] = used_for_row[j];
        }
        pivots[num_pivots++] = col + extra;
        int pivot = matrix[i][col + extra];
        if (col + extra < graphlen) {
            if (abs(pivot) != 1 && abs(pivot) != PH - 1) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
        } else {
            if (abs(pivot) != 2 && abs(pivot) != PH - 2) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
            pivot /= 2;
        }
        matrix[i][col + extra] = pivot;
        for (int j = 0; j < rows; j++) {
            if (j == i) continue;
            int factor = matrix[j][col + extra];
            if (col + extra < graphlen) {
                matrix[j][col + extra] = 0;
                for (int k = col + extra + 1; k < cols; k++) {
                    matrix[j][k] -= matrix[i][k] * factor;
                }
            } else {
                while (matrix[j][col + extra] != 0) {
                    matrix[j] = (matrix[j] - matrix[i]) % PH;
                }
            }
            used_for_row[j] |= used_for_row[i];
        }
        col++;
    }
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] %= PH;
        }
    }
}

// Function to convert a set of integers to an array of integers in C
int** set_to_array(int* set, int size) {
    int* array = malloc(size * sizeof(int));
    int* current = array;
    for (int i = 0; i < size; i++) {
        if (set[i] / 32 != (*current) / 32) {
            (*current)++;
        }
        int index = set[i] % 32;
        array[*current] |= 1 << index;
    }
    int* length = malloc(sizeof(int));
    *length = current - array + 1;
    int** result = malloc(2 * sizeof(int*));
    result[0] = array;
    result[1] = length;
    return result;
}

// Function to perform reduced row echelon form on a matrix
int** rref(int** matrix, int rows, int cols, int graphlen) {
    int** used_for_row = calloc(rows, sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = calloc(rows, sizeof(int));
        used_for_row[i][i / 32] |= 1 << (i % 32);
    }
    gaussian_elimination(matrix, used_for_row, rows, cols, graphlen);
    int** result = set_to_array(used_for_row[0], rows);
    for (int i = 1; i < rows; i++) {
        int* temp = set_to_array(used_for_row[i], rows);
        for (int j = 0; j < *(result[1]); j++) {
            result[0][j] |= temp[j];
        }
        free(temp[0]);
        free(temp[1]);
        free(temp);
    }
    for (int i = 0; i < rows; i++) {
        free(used_for_row[i]);
    }
    free(used_for_row);
    return result;
}



#include<stdio.h>
#include<stdlib.h>
int main() {

int arr0[] = {1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr1[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr2[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr3[] = {0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr4[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr5[] = {0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr6[] = {0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0};
int arr7[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, -30};
int arr8[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr9[] = {0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, -20};
int arr10[] = {1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr11[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr12[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr13[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -14};
int arr14[] = {0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr15[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, -30};
int arr16[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr17[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr18[] = {0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr19[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr20[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr21[] = {0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr22[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, -20};
int arr23[] = {0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr24[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr25[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr26[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr27[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr28[] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr29[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr30[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr31[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr32[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, -10};
int arr33[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr34[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr35[] = {0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -9};
int arr36[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, -20};
int arr37[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, -40};
int arr38[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int* arr[] = {arr0, arr1, arr2, arr3, arr4, arr5, arr6, arr7, arr8, arr9, arr10, arr11, arr12, arr13, arr14, arr15, arr16, arr17, arr18, arr19, arr20, arr21, arr22, arr23, arr24, arr25, arr26, arr27, arr28, arr29, arr30, arr31, arr32, arr33, arr34, arr35, arr36, arr37, arr38};
int** got = rref(arr, 39, 49, 37);


int answer = got[3][0]+got[3][1]+got[3][2]+got[3][3]+got[3][4]+got[3][5]+got[3][6];
int expected = 146;
if (answer != expected) {
    printf("Wrong answer; got %d instead of %d.\n", answer, expected);
    exit(1);
}
printf("All tests passed\n");
}
And got the output: main.c: In function 'gaussian_elimination': main.c:76:31: warning: assignment to 'int *' from 'long int' makes pointer from integer without a cast [-Wint-conversion] 76 | matrix[j] = (matrix[j] - matrix[i]) % PH; | ^ main.c: In function 'rref': main.c:116:34: warning: passing argument 2 of 'gaussian_elimination' from incompatible pointer type [-Wincompatible-pointer-types] 116 | gaussian_elimination(matrix, used_for_row, rows, cols, graphlen); | ^~~~~~~~~~~~ | | | int ** main.c:19:46: note: expected 'int *' but argument is of type 'int **' 19 | void gaussian_elimination(int** matrix, int* used_for_row, int rows, int cols, int graphlen) { | ~~~~~^~~~~~~~~~~~ main.c:119:21: warning: initialization of 'int *' from incompatible pointer type 'int **' [-Wincompatible-pointer-types] 119 | int* temp = set_to_array(used_for_row[i], rows); | ^~~~~~~~~~~~ main.c:123:18: warning: passing argument 1 of 'free' makes pointer from integer without a cast [-Wint-conversion] 123 | free(temp[0]); | ~~~~^~~ | | | int In file included from main.c:3: /usr/include/stdlib.h:555:25: note: expected 'void *' but argument is of type 'int' 555 | extern void free (void *__ptr) __THROW; | ~~~~~~^~~~~ main.c:124:18: warning: passing argument 1 of 'free' makes pointer from integer without a cast [-Wint-conversion] 124 | free(temp[1]); | ~~~~^~~ | | | int In file included from main.c:3: /usr/include/stdlib.h:555:25: note: expected 'void *' but argument is of type 'int' 555 | extern void free (void *__ptr) __THROW; | ~~~~~~^~~~~ main.sh: line 2: 16 Segmentation fault (core dumped) ./a.out

Substring Evaluation

Testing if the previous output contains the string All tests passed: False

Initial Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

LLM Generation

Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

Output

Here's a possible C implementation of the `rref` function: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

#define PH 16

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int** used_for_row = calloc(rows, sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = calloc(rows, sizeof(int));
        used_for_row[i][i] = 1;
    }

    int extra = 0;
    int col = 0;
    int* pivots = calloc(cols, sizeof(int));

    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            if (matrix[col][col + extra + 1] == 0 && matrix[col + 1][col + extra] == 0) {
                extra++;
                continue;
            }
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0 && (other == -1 || i < other)) {
                    other = i;
                }
            }
            if (other < col) {
                extra++;
                continue;
            }
            int tmp = matrix[col][col + extra];
            matrix[col][col + extra] = matrix[other][col + extra];
            matrix[other][col + extra] = tmp;
            for (int j = 0; j < cols; j++) {
                tmp = matrix[col][j];
                matrix[col][j] = matrix[other][j];
                matrix[other][j] = tmp;
            }
            for (int j = 0; j < rows; j++) {
                tmp = used_for_row[j][col];
                used_for_row[j][col] = used_for_row[j][other];
                used_for_row[j][other] = tmp;
            }
        }
        pivots[col] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            if (abs(pivot) != 1 && abs(pivot) != PH - 1) {
                // Error: pivot is not valid
                free(used_for_row);
                free(pivots);
                return NULL;
            }
        } else {
            if (abs(pivot) != 2 && abs(pivot) != PH - 2) {
                // Error: pivot is not valid
                free(used_for_row);
                free(pivots);
                return NULL;
            }
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = matrix[col][j] * pivot % PH;
        }
        for (int i = 0; i < rows; i++) {
            if (i == col) {
                continue;
            }
            int factor = matrix[i][col + extra];
            if (col + extra < graphlen) {
                factor = matrix[col][col + extra] * factor % PH;
            } else {
                while (factor != 0) {
                    factor = (factor - matrix[col][col + extra]) % PH;
                }
            }
            for (int j = 0; j < cols; j++) {
                matrix[i][j] = (matrix[i][j] - matrix[col][j] * factor + PH) % PH;
            }
            used_for_row[i][col] = 1;
        }
        col++;
    }

    free(pivots);
    return used_for_row;
}
Note that this implementation assumes that the input matrix is correctly formatted and that the `malloc` and `calloc` functions do not fail. It also does not handle the error case when the pivot is not valid. You may want to add error handling to make the function more robust.

Extract Code

I extracted the following code from that output: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

#define PH 16

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int** used_for_row = calloc(rows, sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = calloc(rows, sizeof(int));
        used_for_row[i][i] = 1;
    }

    int extra = 0;
    int col = 0;
    int* pivots = calloc(cols, sizeof(int));

    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            if (matrix[col][col + extra + 1] == 0 && matrix[col + 1][col + extra] == 0) {
                extra++;
                continue;
            }
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0 && (other == -1 || i < other)) {
                    other = i;
                }
            }
            if (other < col) {
                extra++;
                continue;
            }
            int tmp = matrix[col][col + extra];
            matrix[col][col + extra] = matrix[other][col + extra];
            matrix[other][col + extra] = tmp;
            for (int j = 0; j < cols; j++) {
                tmp = matrix[col][j];
                matrix[col][j] = matrix[other][j];
                matrix[other][j] = tmp;
            }
            for (int j = 0; j < rows; j++) {
                tmp = used_for_row[j][col];
                used_for_row[j][col] = used_for_row[j][other];
                used_for_row[j][other] = tmp;
            }
        }
        pivots[col] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            if (abs(pivot) != 1 && abs(pivot) != PH - 1) {
                // Error: pivot is not valid
                free(used_for_row);
                free(pivots);
                return NULL;
            }
        } else {
            if (abs(pivot) != 2 && abs(pivot) != PH - 2) {
                // Error: pivot is not valid
                free(used_for_row);
                free(pivots);
                return NULL;
            }
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = matrix[col][j] * pivot % PH;
        }
        for (int i = 0; i < rows; i++) {
            if (i == col) {
                continue;
            }
            int factor = matrix[i][col + extra];
            if (col + extra < graphlen) {
                factor = matrix[col][col + extra] * factor % PH;
            } else {
                while (factor != 0) {
                    factor = (factor - matrix[col][col + extra]) % PH;
                }
            }
            for (int j = 0; j < cols; j++) {
                matrix[i][j] = (matrix[i][j] - matrix[col][j] * factor + PH) % PH;
            }
            used_for_row[i][col] = 1;
        }
        col++;
    }

    free(pivots);
    return used_for_row;
}

Run Code Interpreter

Running the following program: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

#define PH 16

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int** used_for_row = calloc(rows, sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = calloc(rows, sizeof(int));
        used_for_row[i][i] = 1;
    }

    int extra = 0;
    int col = 0;
    int* pivots = calloc(cols, sizeof(int));

    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            if (matrix[col][col + extra + 1] == 0 && matrix[col + 1][col + extra] == 0) {
                extra++;
                continue;
            }
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0 && (other == -1 || i < other)) {
                    other = i;
                }
            }
            if (other < col) {
                extra++;
                continue;
            }
            int tmp = matrix[col][col + extra];
            matrix[col][col + extra] = matrix[other][col + extra];
            matrix[other][col + extra] = tmp;
            for (int j = 0; j < cols; j++) {
                tmp = matrix[col][j];
                matrix[col][j] = matrix[other][j];
                matrix[other][j] = tmp;
            }
            for (int j = 0; j < rows; j++) {
                tmp = used_for_row[j][col];
                used_for_row[j][col] = used_for_row[j][other];
                used_for_row[j][other] = tmp;
            }
        }
        pivots[col] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            if (abs(pivot) != 1 && abs(pivot) != PH - 1) {
                // Error: pivot is not valid
                free(used_for_row);
                free(pivots);
                return NULL;
            }
        } else {
            if (abs(pivot) != 2 && abs(pivot) != PH - 2) {
                // Error: pivot is not valid
                free(used_for_row);
                free(pivots);
                return NULL;
            }
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = matrix[col][j] * pivot % PH;
        }
        for (int i = 0; i < rows; i++) {
            if (i == col) {
                continue;
            }
            int factor = matrix[i][col + extra];
            if (col + extra < graphlen) {
                factor = matrix[col][col + extra] * factor % PH;
            } else {
                while (factor != 0) {
                    factor = (factor - matrix[col][col + extra]) % PH;
                }
            }
            for (int j = 0; j < cols; j++) {
                matrix[i][j] = (matrix[i][j] - matrix[col][j] * factor + PH) % PH;
            }
            used_for_row[i][col] = 1;
        }
        col++;
    }

    free(pivots);
    return used_for_row;
}



#include<stdio.h>
#include<stdlib.h>
int main() {

int arr0[] = {1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr1[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr2[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr3[] = {0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr4[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr5[] = {0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr6[] = {0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0};
int arr7[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, -30};
int arr8[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr9[] = {0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, -20};
int arr10[] = {1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr11[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr12[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr13[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -14};
int arr14[] = {0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr15[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, -30};
int arr16[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr17[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr18[] = {0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr19[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr20[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr21[] = {0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr22[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, -20};
int arr23[] = {0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr24[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr25[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr26[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr27[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr28[] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr29[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr30[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr31[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr32[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, -10};
int arr33[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr34[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr35[] = {0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -9};
int arr36[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, -20};
int arr37[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, -40};
int arr38[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int* arr[] = {arr0, arr1, arr2, arr3, arr4, arr5, arr6, arr7, arr8, arr9, arr10, arr11, arr12, arr13, arr14, arr15, arr16, arr17, arr18, arr19, arr20, arr21, arr22, arr23, arr24, arr25, arr26, arr27, arr28, arr29, arr30, arr31, arr32, arr33, arr34, arr35, arr36, arr37, arr38};
int** got = rref(arr, 39, 49, 37);


int answer = got[3][0]+got[3][1]+got[3][2]+got[3][3]+got[3][4]+got[3][5]+got[3][6];
int expected = 146;
if (answer != expected) {
    printf("Wrong answer; got %d instead of %d.\n", answer, expected);
    exit(1);
}
printf("All tests passed\n");
}
And got the output: main.sh: line 2: 16 Segmentation fault (core dumped) ./a.out

Substring Evaluation

Testing if the previous output contains the string All tests passed: False

Initial Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

LLM Generation

Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

Output

Here's a possible implementation of the function `rref` in C: 

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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>

// Define the constant PH
#define PH 16

// Define a struct to represent a set of integers
typedef struct {
    int *elements;
    int size;
    int capacity;
} Set;

// Function to initialize a set
Set *create_set() {
    Set *set = (Set *) malloc(sizeof(Set));
    set->elements = (int *) malloc(10 * sizeof(int));
    set->size = 0;
    set->capacity = 10;
    return set;
}

// Function to add an element to a set
void add_to_set(Set *set, int element) {
    if (set->size == set->capacity) {
        set->capacity *= 2;
        set->elements = (int *) realloc(set->elements, set->capacity * sizeof(int));
    }
    set->elements[set->size++] = element;
}

// Function to find the union of two sets
Set *union_sets(Set *set1, Set *set2) {
    Set *result = create_set();
    for (int i = 0; i < set1->size; i++) {
        add_to_set(result, set1->elements[i]);
    }
    for (int i = 0; i < set2->size; i++) {
        bool found = false;
        for (int j = 0; j < result->size; j++) {
            if (result->elements[j] == set2->elements[i]) {
                found = true;
                break;
            }
        }
        if (!found) {
            add_to_set(result, set2->elements[i]);
        }
    }
    return result;
}

// Function to free the memory used by a set
void free_set(Set *set) {
    free(set->elements);
    free(set);
}

// Function to perform reduced row echelon form on a matrix
int **rref(int **matrix, int rows, int cols, int graphlen) {
    // Create an array of sets to represent used_for_row
    Set **used_for_row = (Set **) malloc(rows * sizeof(Set *));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set();
        add_to_set(used_for_row[i], i);
    }

    int extra = 0;
    int col = 0;
    int *pivots = (int *) malloc((cols - graphlen) * sizeof(int));

    // Loop through the columns of the matrix
    while (col + extra < cols - 1 && col < rows) {
        int pivot_row = -1;
        int max_abs = -1;
        // Find the pivot element
        for (int i = col; i < rows; i++) {
            int val = abs(matrix[i][col + extra] % PH);
            if (val > max_abs) {
                max_abs = val;
                pivot_row = i;
            }
        }
        if (pivot_row == -1) {
            extra++;
            continue;
        }
        if (matrix[col][col + extra] == 0) {
            int tmp = matrix[col][col + extra];
            for (int k = col + extra; k < cols; k++) {
                int t = matrix[col][k];
                matrix[col][k] = matrix[pivot_row][k];
                matrix[pivot_row][k] = t;
            }
            tmp = matrix[col][col + extra];
            for (int k = col + extra; k < cols; k++) {
                int t = matrix[col][k];
                matrix[col][k] = matrix[pivot_row][k];
                matrix[pivot_row][k] = t;
            }
            Set *tmp_set = used_for_row[col];
            used_for_row[col] = used_for_row[pivot_row];
            used_for_row[pivot_row] = tmp_set;
        }
        pivots[col] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col < graphlen) {
            if (pivot != 1 && pivot != PH - 1) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
        } else {
            if (pivot != 2 && pivot != PH - 2) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        for (int i = 0; i < rows; i++) {
            if (i == col) {
                continue;
            }
            int factor = matrix[i][col + extra];
            if (col < graphlen) {
                matrix[i][col + extra] = 0;
                for (int k = col + extra + 1; k < cols; k++) {
                    matrix[i][k] -= matrix[col][k] * factor;
                }
            } else {
                while (matrix[i][col + extra] != 0) {
                    matrix[i][col + extra] -= pivot;
                    if (matrix[i][col + extra] < 0) {
                        matrix[i][col + extra] += PH;
                    }
                    for (int k = col + extra + 1; k < cols; k++) {
                        matrix[i][k] -= matrix[col][k];
                        if (matrix[i][k] < 0) {
                            matrix[i][k] += PH;
                        }
                    }
                }
            }
        }
        col++;
    }

    // Create an array of arrays to represent the final result
    int **result = (int **) malloc(rows * sizeof(int *));
    for (int i = 0; i < rows; i++) {
        result[i] = (int *) malloc(used_for_row[i]->size * sizeof(int));
        for (int j = 0; j < used_for_row[i]->size; j++) {
            result[i][j] = used_for_row[i]->elements[j];
        }
        free_set(used_for_row[i]);
    }
    free(used_for_row);
    free(pivots);

    // Return the result
    return result;
}
Note that this implementation uses a `Set` struct to represent sets of integers, and provides functions to initialize, add elements to, find the union of, and free the memory used by sets. The implementation of the `rref` function itself is similar to the original Python implementation, with some modifications to handle the differences between the two languages (e.g., using arrays instead of NumPy arrays, using `malloc` and `free` instead of Python's memory management, etc.).

Extract Code

I extracted the following code from that output: 

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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>

// Define the constant PH
#define PH 16

// Define a struct to represent a set of integers
typedef struct {
    int *elements;
    int size;
    int capacity;
} Set;

// Function to initialize a set
Set *create_set() {
    Set *set = (Set *) malloc(sizeof(Set));
    set->elements = (int *) malloc(10 * sizeof(int));
    set->size = 0;
    set->capacity = 10;
    return set;
}

// Function to add an element to a set
void add_to_set(Set *set, int element) {
    if (set->size == set->capacity) {
        set->capacity *= 2;
        set->elements = (int *) realloc(set->elements, set->capacity * sizeof(int));
    }
    set->elements[set->size++] = element;
}

// Function to find the union of two sets
Set *union_sets(Set *set1, Set *set2) {
    Set *result = create_set();
    for (int i = 0; i < set1->size; i++) {
        add_to_set(result, set1->elements[i]);
    }
    for (int i = 0; i < set2->size; i++) {
        bool found = false;
        for (int j = 0; j < result->size; j++) {
            if (result->elements[j] == set2->elements[i]) {
                found = true;
                break;
            }
        }
        if (!found) {
            add_to_set(result, set2->elements[i]);
        }
    }
    return result;
}

// Function to free the memory used by a set
void free_set(Set *set) {
    free(set->elements);
    free(set);
}

// Function to perform reduced row echelon form on a matrix
int **rref(int **matrix, int rows, int cols, int graphlen) {
    // Create an array of sets to represent used_for_row
    Set **used_for_row = (Set **) malloc(rows * sizeof(Set *));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set();
        add_to_set(used_for_row[i], i);
    }

    int extra = 0;
    int col = 0;
    int *pivots = (int *) malloc((cols - graphlen) * sizeof(int));

    // Loop through the columns of the matrix
    while (col + extra < cols - 1 && col < rows) {
        int pivot_row = -1;
        int max_abs = -1;
        // Find the pivot element
        for (int i = col; i < rows; i++) {
            int val = abs(matrix[i][col + extra] % PH);
            if (val > max_abs) {
                max_abs = val;
                pivot_row = i;
            }
        }
        if (pivot_row == -1) {
            extra++;
            continue;
        }
        if (matrix[col][col + extra] == 0) {
            int tmp = matrix[col][col + extra];
            for (int k = col + extra; k < cols; k++) {
                int t = matrix[col][k];
                matrix[col][k] = matrix[pivot_row][k];
                matrix[pivot_row][k] = t;
            }
            tmp = matrix[col][col + extra];
            for (int k = col + extra; k < cols; k++) {
                int t = matrix[col][k];
                matrix[col][k] = matrix[pivot_row][k];
                matrix[pivot_row][k] = t;
            }
            Set *tmp_set = used_for_row[col];
            used_for_row[col] = used_for_row[pivot_row];
            used_for_row[pivot_row] = tmp_set;
        }
        pivots[col] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col < graphlen) {
            if (pivot != 1 && pivot != PH - 1) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
        } else {
            if (pivot != 2 && pivot != PH - 2) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        for (int i = 0; i < rows; i++) {
            if (i == col) {
                continue;
            }
            int factor = matrix[i][col + extra];
            if (col < graphlen) {
                matrix[i][col + extra] = 0;
                for (int k = col + extra + 1; k < cols; k++) {
                    matrix[i][k] -= matrix[col][k] * factor;
                }
            } else {
                while (matrix[i][col + extra] != 0) {
                    matrix[i][col + extra] -= pivot;
                    if (matrix[i][col + extra] < 0) {
                        matrix[i][col + extra] += PH;
                    }
                    for (int k = col + extra + 1; k < cols; k++) {
                        matrix[i][k] -= matrix[col][k];
                        if (matrix[i][k] < 0) {
                            matrix[i][k] += PH;
                        }
                    }
                }
            }
        }
        col++;
    }

    // Create an array of arrays to represent the final result
    int **result = (int **) malloc(rows * sizeof(int *));
    for (int i = 0; i < rows; i++) {
        result[i] = (int *) malloc(used_for_row[i]->size * sizeof(int));
        for (int j = 0; j < used_for_row[i]->size; j++) {
            result[i][j] = used_for_row[i]->elements[j];
        }
        free_set(used_for_row[i]);
    }
    free(used_for_row);
    free(pivots);

    // Return the result
    return result;
}

Run Code Interpreter

Running the following program: 

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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>

// Define the constant PH
#define PH 16

// Define a struct to represent a set of integers
typedef struct {
    int *elements;
    int size;
    int capacity;
} Set;

// Function to initialize a set
Set *create_set() {
    Set *set = (Set *) malloc(sizeof(Set));
    set->elements = (int *) malloc(10 * sizeof(int));
    set->size = 0;
    set->capacity = 10;
    return set;
}

// Function to add an element to a set
void add_to_set(Set *set, int element) {
    if (set->size == set->capacity) {
        set->capacity *= 2;
        set->elements = (int *) realloc(set->elements, set->capacity * sizeof(int));
    }
    set->elements[set->size++] = element;
}

// Function to find the union of two sets
Set *union_sets(Set *set1, Set *set2) {
    Set *result = create_set();
    for (int i = 0; i < set1->size; i++) {
        add_to_set(result, set1->elements[i]);
    }
    for (int i = 0; i < set2->size; i++) {
        bool found = false;
        for (int j = 0; j < result->size; j++) {
            if (result->elements[j] == set2->elements[i]) {
                found = true;
                break;
            }
        }
        if (!found) {
            add_to_set(result, set2->elements[i]);
        }
    }
    return result;
}

// Function to free the memory used by a set
void free_set(Set *set) {
    free(set->elements);
    free(set);
}

// Function to perform reduced row echelon form on a matrix
int **rref(int **matrix, int rows, int cols, int graphlen) {
    // Create an array of sets to represent used_for_row
    Set **used_for_row = (Set **) malloc(rows * sizeof(Set *));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set();
        add_to_set(used_for_row[i], i);
    }

    int extra = 0;
    int col = 0;
    int *pivots = (int *) malloc((cols - graphlen) * sizeof(int));

    // Loop through the columns of the matrix
    while (col + extra < cols - 1 && col < rows) {
        int pivot_row = -1;
        int max_abs = -1;
        // Find the pivot element
        for (int i = col; i < rows; i++) {
            int val = abs(matrix[i][col + extra] % PH);
            if (val > max_abs) {
                max_abs = val;
                pivot_row = i;
            }
        }
        if (pivot_row == -1) {
            extra++;
            continue;
        }
        if (matrix[col][col + extra] == 0) {
            int tmp = matrix[col][col + extra];
            for (int k = col + extra; k < cols; k++) {
                int t = matrix[col][k];
                matrix[col][k] = matrix[pivot_row][k];
                matrix[pivot_row][k] = t;
            }
            tmp = matrix[col][col + extra];
            for (int k = col + extra; k < cols; k++) {
                int t = matrix[col][k];
                matrix[col][k] = matrix[pivot_row][k];
                matrix[pivot_row][k] = t;
            }
            Set *tmp_set = used_for_row[col];
            used_for_row[col] = used_for_row[pivot_row];
            used_for_row[pivot_row] = tmp_set;
        }
        pivots[col] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col < graphlen) {
            if (pivot != 1 && pivot != PH - 1) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
        } else {
            if (pivot != 2 && pivot != PH - 2) {
                printf("Error: invalid pivot value\n");
                exit(1);
            }
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        for (int i = 0; i < rows; i++) {
            if (i == col) {
                continue;
            }
            int factor = matrix[i][col + extra];
            if (col < graphlen) {
                matrix[i][col + extra] = 0;
                for (int k = col + extra + 1; k < cols; k++) {
                    matrix[i][k] -= matrix[col][k] * factor;
                }
            } else {
                while (matrix[i][col + extra] != 0) {
                    matrix[i][col + extra] -= pivot;
                    if (matrix[i][col + extra] < 0) {
                        matrix[i][col + extra] += PH;
                    }
                    for (int k = col + extra + 1; k < cols; k++) {
                        matrix[i][k] -= matrix[col][k];
                        if (matrix[i][k] < 0) {
                            matrix[i][k] += PH;
                        }
                    }
                }
            }
        }
        col++;
    }

    // Create an array of arrays to represent the final result
    int **result = (int **) malloc(rows * sizeof(int *));
    for (int i = 0; i < rows; i++) {
        result[i] = (int *) malloc(used_for_row[i]->size * sizeof(int));
        for (int j = 0; j < used_for_row[i]->size; j++) {
            result[i][j] = used_for_row[i]->elements[j];
        }
        free_set(used_for_row[i]);
    }
    free(used_for_row);
    free(pivots);

    // Return the result
    return result;
}



#include<stdio.h>
#include<stdlib.h>
int main() {

int arr0[] = {1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr1[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr2[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr3[] = {0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr4[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr5[] = {0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr6[] = {0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0};
int arr7[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, -30};
int arr8[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr9[] = {0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, -20};
int arr10[] = {1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr11[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr12[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr13[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -14};
int arr14[] = {0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr15[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, -30};
int arr16[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr17[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr18[] = {0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr19[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr20[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr21[] = {0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr22[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, -20};
int arr23[] = {0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr24[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr25[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr26[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr27[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr28[] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr29[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr30[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr31[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr32[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, -10};
int arr33[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr34[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr35[] = {0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -9};
int arr36[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, -20};
int arr37[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, -40};
int arr38[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int* arr[] = {arr0, arr1, arr2, arr3, arr4, arr5, arr6, arr7, arr8, arr9, arr10, arr11, arr12, arr13, arr14, arr15, arr16, arr17, arr18, arr19, arr20, arr21, arr22, arr23, arr24, arr25, arr26, arr27, arr28, arr29, arr30, arr31, arr32, arr33, arr34, arr35, arr36, arr37, arr38};
int** got = rref(arr, 39, 49, 37);


int answer = got[3][0]+got[3][1]+got[3][2]+got[3][3]+got[3][4]+got[3][5]+got[3][6];
int expected = 146;
if (answer != expected) {
    printf("Wrong answer; got %d instead of %d.\n", answer, expected);
    exit(1);
}
printf("All tests passed\n");
}
And got the output: Error: invalid pivot value

Substring Evaluation

Testing if the previous output contains the string All tests passed: False

Initial Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

LLM Generation

Query

Rewrite this function in C. You can assume that the input is a 2d matrix correctly formatted. Call it rref(int** matrix, int rows, int cols, int graphlen) where the size is matrix[rows][cols]. Return an int** of used_for_row. def rref(matrix, graphlen): PH = 16 extra = 0 col = 0 pivots = [] used_for_row = [set([i]) for i in range(matrix.shape[0])] matrix = matrix%PH while col+extra < matrix.shape[1]-1 and col < matrix.shape[0]: if matrix[col,col+extra] == 0: if np.all(matrix[:,col] == 0): extra += 1 continue other = np.argwhere(matrix[:,col+extra] != 0).flatten()[-1] if other < col: extra += 1 continue matrix[col], matrix[other] = list(matrix[other]), list(matrix[col]) used_for_row[col], used_for_row[other] = used_for_row[other], used_for_row[col] pivots.append(col+extra) pivot = matrix[col,col+extra] if col+extra < graphlen: assert np.abs(pivot) == 1 or np.abs(pivot) == PH-1 else: assert np.abs(pivot) == 2 or np.abs(pivot) == PH-2 pivot //= 2 matrix[col] *= pivot matrix[col] %= PH others = np.argwhere(matrix[:,col+extra]).flatten() for i in others: if i == col: continue used_for_row[i] |= used_for_row[col] if col < graphlen: matrix[i] -= matrix[col]*matrix[i,col+extra] else: while matrix[i,col+extra] != 0: matrix[i] = (matrix[i]-matrix[col])%PH matrix[i] %= PH col += 1 matrix = np.array(matrix)%PH return [sorted(x) for x in used_for_row]

Output

Here's a possible C implementation of the function, based on the provided Python code: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#define PH 16

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int* used_for_row = calloc(rows, sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = i;
    }

    int extra = 0;
    int col = 0;
    int pivots[rows];
    int num_pivots = 0;
    bool swap_needed = false;

    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            if (all_zeroes(matrix[col], cols)) {
                extra++;
                continue;
            }
            int other = find_first_nonzero(matrix, col + extra, cols);
            if (other < col) {
                extra++;
                continue;
            }

            swap_rows(matrix, col, other, cols);
            swap_ints(&used_for_row[col], &used_for_row[other]);
            swap_needed = true;
        }

        pivots[num_pivots] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            assert(abs(pivot) == 1 || abs(pivot) == PH - 1);
        } else {
            assert(abs(pivot) == 2 || abs(pivot) == PH - 2);
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        matrix[col] %= PH;

        int* others = find_nonzeroes(matrix, col + extra, rows, cols);
        for (int i = 0; others[i] != -1; i++) {
            int row = others[i];
            if (row == col) continue;
            used_for_row[row] = add_if_not_present(used_for_row[row], used_for_row[col]);
            if (col < graphlen) {
                matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], matrix[row][col + extra]);
            } else {
                while (matrix[row][col + extra] != 0) {
                    matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], 1);
                }
            }
            matrix[row] %= PH;
        }
        free(others);

        col++;
    }

    if (swap_needed) {
        for (int i = 0; i < rows; i++) {
            int tmp = used_for_row[i];
            used_for_row[i] = used_for_row[matrix[i][0]];
            used_for_row[matrix[i][0]] = tmp;
        }
    }

    int** result = malloc(rows * sizeof(int*));
    for (int i = 0; i < rows; i++) {
        int len = count_set_bits(used_for_row[i]) + 1;
        result[i] = malloc(len * sizeof(int));
        int j = 0;
        for (int k = 0; k < rows; k++) {
            if (used_for_row[i] & (1 << k)) {
                result[i][j++] = k;
            }
        }
        qsort(result[i], len, sizeof(int), compare_ints);
    }

    free(used_for_row);
    return result;
}

bool all_zeroes(int* row, int cols) {
    for (int i = 0; i < cols; i++) {
        if (row[i] != 0) {
            return false;
        }
    }
    return true;
}

int find_first_nonzero(int** matrix, int col, int cols) {
    for (int i = 0; i < cols; i++) {
        for (int j = col; j < cols; j++) {
            if (matrix[i][j] != 0) {
                return i;
            }
        }
    }
    return -1;
}

void swap_rows(int** matrix, int i, int j, int cols) {
    int tmp[cols];
    memcpy(tmp, matrix[i], cols * sizeof(int));
    memcpy(matrix[i], matrix[j], cols * sizeof(int));
    memcpy(matrix[j], tmp, cols * sizeof(int));
}

void swap_ints(int* a, int* b) {
    int tmp = *a;
    *a = *b;
    *b = tmp;
}

int* find_nonzeroes(int** matrix, int col, int rows, int cols) {
    int count = 0;
    for (int i = 0; i < rows; i++) {
        if (matrix[i][col] != 0) {
            count++;
        }
    }

    int* result = malloc(count * sizeof(int));
    int idx = 0;
    for (int i = 0; i < rows; i++) {
        if (matrix[i][col] != 0) {
            result[idx++] = i;
        }
    }
    result[idx] = -1;
    return result;
}

int add_if_not_present(int a, int b) {
    int result = a;
    if ((result & b) == 0) {
        result |= b;
    }
    return result;
}

int count_set_bits(int n) {
    int count = 0;
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}

int compare_ints(const void* a, const void* b) {
    return (*(int*)a - *(int*)b);
}

int subtract_rows_mod_PH(int* row1, int* row2, int scalar) {
    for (int i = 0; i < cols; i++) {
        row1[i] = ((row1[i] - scalar * row2[i]) % PH + PH) % PH;
    }
    return 0;
}
Note that this implementation assumes a column-major ordering of the matrix elements in memory, and uses a sentinel value (-1) to mark the end of arrays. The function returns an array of arrays, where each subarray contains the indices of the rows used to compute the corresponding row of the reduced row echelon form of the input matrix. The function also assumes that the input matrix is correctly formatted, as stated in the prompt.

Extract Code

I extracted the following code from that output: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#define PH 16

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int* used_for_row = calloc(rows, sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = i;
    }

    int extra = 0;
    int col = 0;
    int pivots[rows];
    int num_pivots = 0;
    bool swap_needed = false;

    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            if (all_zeroes(matrix[col], cols)) {
                extra++;
                continue;
            }
            int other = find_first_nonzero(matrix, col + extra, cols);
            if (other < col) {
                extra++;
                continue;
            }

            swap_rows(matrix, col, other, cols);
            swap_ints(&used_for_row[col], &used_for_row[other]);
            swap_needed = true;
        }

        pivots[num_pivots] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            assert(abs(pivot) == 1 || abs(pivot) == PH - 1);
        } else {
            assert(abs(pivot) == 2 || abs(pivot) == PH - 2);
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        matrix[col] %= PH;

        int* others = find_nonzeroes(matrix, col + extra, rows, cols);
        for (int i = 0; others[i] != -1; i++) {
            int row = others[i];
            if (row == col) continue;
            used_for_row[row] = add_if_not_present(used_for_row[row], used_for_row[col]);
            if (col < graphlen) {
                matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], matrix[row][col + extra]);
            } else {
                while (matrix[row][col + extra] != 0) {
                    matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], 1);
                }
            }
            matrix[row] %= PH;
        }
        free(others);

        col++;
    }

    if (swap_needed) {
        for (int i = 0; i < rows; i++) {
            int tmp = used_for_row[i];
            used_for_row[i] = used_for_row[matrix[i][0]];
            used_for_row[matrix[i][0]] = tmp;
        }
    }

    int** result = malloc(rows * sizeof(int*));
    for (int i = 0; i < rows; i++) {
        int len = count_set_bits(used_for_row[i]) + 1;
        result[i] = malloc(len * sizeof(int));
        int j = 0;
        for (int k = 0; k < rows; k++) {
            if (used_for_row[i] & (1 << k)) {
                result[i][j++] = k;
            }
        }
        qsort(result[i], len, sizeof(int), compare_ints);
    }

    free(used_for_row);
    return result;
}

bool all_zeroes(int* row, int cols) {
    for (int i = 0; i < cols; i++) {
        if (row[i] != 0) {
            return false;
        }
    }
    return true;
}

int find_first_nonzero(int** matrix, int col, int cols) {
    for (int i = 0; i < cols; i++) {
        for (int j = col; j < cols; j++) {
            if (matrix[i][j] != 0) {
                return i;
            }
        }
    }
    return -1;
}

void swap_rows(int** matrix, int i, int j, int cols) {
    int tmp[cols];
    memcpy(tmp, matrix[i], cols * sizeof(int));
    memcpy(matrix[i], matrix[j], cols * sizeof(int));
    memcpy(matrix[j], tmp, cols * sizeof(int));
}

void swap_ints(int* a, int* b) {
    int tmp = *a;
    *a = *b;
    *b = tmp;
}

int* find_nonzeroes(int** matrix, int col, int rows, int cols) {
    int count = 0;
    for (int i = 0; i < rows; i++) {
        if (matrix[i][col] != 0) {
            count++;
        }
    }

    int* result = malloc(count * sizeof(int));
    int idx = 0;
    for (int i = 0; i < rows; i++) {
        if (matrix[i][col] != 0) {
            result[idx++] = i;
        }
    }
    result[idx] = -1;
    return result;
}

int add_if_not_present(int a, int b) {
    int result = a;
    if ((result & b) == 0) {
        result |= b;
    }
    return result;
}

int count_set_bits(int n) {
    int count = 0;
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}

int compare_ints(const void* a, const void* b) {
    return (*(int*)a - *(int*)b);
}

int subtract_rows_mod_PH(int* row1, int* row2, int scalar) {
    for (int i = 0; i < cols; i++) {
        row1[i] = ((row1[i] - scalar * row2[i]) % PH + PH) % PH;
    }
    return 0;
}

Run Code Interpreter

Running the following program: 

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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#define PH 16

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int* used_for_row = calloc(rows, sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = i;
    }

    int extra = 0;
    int col = 0;
    int pivots[rows];
    int num_pivots = 0;
    bool swap_needed = false;

    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            if (all_zeroes(matrix[col], cols)) {
                extra++;
                continue;
            }
            int other = find_first_nonzero(matrix, col + extra, cols);
            if (other < col) {
                extra++;
                continue;
            }

            swap_rows(matrix, col, other, cols);
            swap_ints(&used_for_row[col], &used_for_row[other]);
            swap_needed = true;
        }

        pivots[num_pivots] = col + extra;
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            assert(abs(pivot) == 1 || abs(pivot) == PH - 1);
        } else {
            assert(abs(pivot) == 2 || abs(pivot) == PH - 2);
            pivot /= 2;
        }
        matrix[col][col + extra] = pivot;
        matrix[col] %= PH;

        int* others = find_nonzeroes(matrix, col + extra, rows, cols);
        for (int i = 0; others[i] != -1; i++) {
            int row = others[i];
            if (row == col) continue;
            used_for_row[row] = add_if_not_present(used_for_row[row], used_for_row[col]);
            if (col < graphlen) {
                matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], matrix[row][col + extra]);
            } else {
                while (matrix[row][col + extra] != 0) {
                    matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], 1);
                }
            }
            matrix[row] %= PH;
        }
        free(others);

        col++;
    }

    if (swap_needed) {
        for (int i = 0; i < rows; i++) {
            int tmp = used_for_row[i];
            used_for_row[i] = used_for_row[matrix[i][0]];
            used_for_row[matrix[i][0]] = tmp;
        }
    }

    int** result = malloc(rows * sizeof(int*));
    for (int i = 0; i < rows; i++) {
        int len = count_set_bits(used_for_row[i]) + 1;
        result[i] = malloc(len * sizeof(int));
        int j = 0;
        for (int k = 0; k < rows; k++) {
            if (used_for_row[i] & (1 << k)) {
                result[i][j++] = k;
            }
        }
        qsort(result[i], len, sizeof(int), compare_ints);
    }

    free(used_for_row);
    return result;
}

bool all_zeroes(int* row, int cols) {
    for (int i = 0; i < cols; i++) {
        if (row[i] != 0) {
            return false;
        }
    }
    return true;
}

int find_first_nonzero(int** matrix, int col, int cols) {
    for (int i = 0; i < cols; i++) {
        for (int j = col; j < cols; j++) {
            if (matrix[i][j] != 0) {
                return i;
            }
        }
    }
    return -1;
}

void swap_rows(int** matrix, int i, int j, int cols) {
    int tmp[cols];
    memcpy(tmp, matrix[i], cols * sizeof(int));
    memcpy(matrix[i], matrix[j], cols * sizeof(int));
    memcpy(matrix[j], tmp, cols * sizeof(int));
}

void swap_ints(int* a, int* b) {
    int tmp = *a;
    *a = *b;
    *b = tmp;
}

int* find_nonzeroes(int** matrix, int col, int rows, int cols) {
    int count = 0;
    for (int i = 0; i < rows; i++) {
        if (matrix[i][col] != 0) {
            count++;
        }
    }

    int* result = malloc(count * sizeof(int));
    int idx = 0;
    for (int i = 0; i < rows; i++) {
        if (matrix[i][col] != 0) {
            result[idx++] = i;
        }
    }
    result[idx] = -1;
    return result;
}

int add_if_not_present(int a, int b) {
    int result = a;
    if ((result & b) == 0) {
        result |= b;
    }
    return result;
}

int count_set_bits(int n) {
    int count = 0;
    while (n) {
        n &= (n - 1);
        count++;
    }
    return count;
}

int compare_ints(const void* a, const void* b) {
    return (*(int*)a - *(int*)b);
}

int subtract_rows_mod_PH(int* row1, int* row2, int scalar) {
    for (int i = 0; i < cols; i++) {
        row1[i] = ((row1[i] - scalar * row2[i]) % PH + PH) % PH;
    }
    return 0;
}



#include<stdio.h>
#include<stdlib.h>
int main() {

int arr0[] = {1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr1[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr2[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr3[] = {0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, -20};
int arr4[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr5[] = {0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr6[] = {0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, 0};
int arr7[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, -30};
int arr8[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr9[] = {0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, -20};
int arr10[] = {1, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
int arr11[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr12[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr13[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -14};
int arr14[] = {0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr15[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, 0, -30};
int arr16[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr17[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr18[] = {0, 0, 0, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr19[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr20[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr21[] = {0, 0, 0, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr22[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, 0, -20};
int arr23[] = {0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -10};
int arr24[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr25[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr26[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr27[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr28[] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr29[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr30[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int arr31[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr32[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, 0, -10};
int arr33[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -13};
int arr34[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -11};
int arr35[] = {0, 0, 1, 0, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -9};
int arr36[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, 0, -20};
int arr37[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -2, -40};
int arr38[] = {1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
int* arr[] = {arr0, arr1, arr2, arr3, arr4, arr5, arr6, arr7, arr8, arr9, arr10, arr11, arr12, arr13, arr14, arr15, arr16, arr17, arr18, arr19, arr20, arr21, arr22, arr23, arr24, arr25, arr26, arr27, arr28, arr29, arr30, arr31, arr32, arr33, arr34, arr35, arr36, arr37, arr38};
int** got = rref(arr, 39, 49, 37);


int answer = got[3][0]+got[3][1]+got[3][2]+got[3][3]+got[3][4]+got[3][5]+got[3][6];
int expected = 146;
if (answer != expected) {
    printf("Wrong answer; got %d instead of %d.\n", answer, expected);
    exit(1);
}
printf("All tests passed\n");
}
And got the output: main.c: In function 'rref': main.c:23:17: warning: implicit declaration of function 'all_zeroes' [-Wimplicit-function-declaration] 23 | if (all_zeroes(matrix[col], cols)) { | ^~~~~~~~~~ main.c:27:25: warning: implicit declaration of function 'find_first_nonzero' [-Wimplicit-function-declaration] 27 | int other = find_first_nonzero(matrix, col + extra, cols); | ^~~~~~~~~~~~~~~~~~ main.c:33:13: warning: implicit declaration of function 'swap_rows' [-Wimplicit-function-declaration] 33 | swap_rows(matrix, col, other, cols); | ^~~~~~~~~ main.c:34:13: warning: implicit declaration of function 'swap_ints' [-Wimplicit-function-declaration] 34 | swap_ints(&used_for_row[col], &used_for_row[other]); | ^~~~~~~~~ main.c:41:13: warning: implicit declaration of function 'assert' [-Wimplicit-function-declaration] 41 | assert(abs(pivot) == 1 || abs(pivot) == PH - 1); | ^~~~~~ main.c:6:1: note: 'assert' is defined in header '<assert.h>'; did you forget to '#include <assert.h>'? 5 | #include <stdlib.h> +++ |+#include <assert.h> 6 | main.c:47:21: error: invalid operands to binary % (have 'int *' and 'int') 47 | matrix[col] %= PH; | ^~ main.c:49:23: warning: implicit declaration of function 'find_nonzeroes' [-Wimplicit-function-declaration] 49 | int* others = find_nonzeroes(matrix, col + extra, rows, cols); | ^~~~~~~~~~~~~~ main.c:49:23: warning: initialization of 'int *' from 'int' makes pointer from integer without a cast [-Wint-conversion] main.c:53:33: warning: implicit declaration of function 'add_if_not_present' [-Wimplicit-function-declaration] 53 | used_for_row[row] = add_if_not_present(used_for_row[row], used_for_row[col]); | ^~~~~~~~~~~~~~~~~~ main.c:55:31: warning: implicit declaration of function 'subtract_rows_mod_PH' [-Wimplicit-function-declaration] 55 | matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], matrix[row][col + extra]); | ^~~~~~~~~~~~~~~~~~~~ main.c:55:29: warning: assignment to 'int *' from 'int' makes pointer from integer without a cast [-Wint-conversion] 55 | matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], matrix[row][col + extra]); | ^ main.c:58:33: warning: assignment to 'int *' from 'int' makes pointer from integer without a cast [-Wint-conversion] 58 | matrix[row] = subtract_rows_mod_PH(matrix[row], matrix[col], 1); | ^ main.c:61:25: error: invalid operands to binary % (have 'int *' and 'int') 61 | matrix[row] %= PH; | ^~ main.c:78:19: warning: implicit declaration of function 'count_set_bits' [-Wimplicit-function-declaration] 78 | int len = count_set_bits(used_for_row[i]) + 1; | ^~~~~~~~~~~~~~ main.c:86:44: error: 'compare_ints' undeclared (first use in this function) 86 | qsort(result[i], len, sizeof(int), compare_ints); | ^~~~~~~~~~~~ main.c:86:44: note: each undeclared identifier is reported only once for each function it appears in main.c: At top level: main.c:93:6: error: conflicting types for 'all_zeroes'; have '_Bool(int *, int)' 93 | bool all_zeroes(int* row, int cols) { | ^~~~~~~~~~ main.c:23:17: note: previous implicit declaration of 'all_zeroes' with type 'int()' 23 | if (all_zeroes(matrix[col], cols)) { | ^~~~~~~~~~ main.c:113:6: warning: conflicting types for 'swap_rows'; have 'void(int **, int, int, int)' 113 | void swap_rows(int** matrix, int i, int j, int cols) { | ^~~~~~~~~ main.c:33:13: note: previous implicit declaration of 'swap_rows' with type 'void(int **, int, int, int)' 33 | swap_rows(matrix, col, other, cols); | ^~~~~~~~~ main.c: In function 'swap_rows': main.c:115:5: warning: implicit declaration of function 'memcpy' [-Wimplicit-function-declaration] 115 | memcpy(tmp, matrix[i], cols * sizeof(int)); | ^~~~~~ main.c:6:1: note: include '<string.h>' or provide a declaration of 'memcpy' 5 | #include <stdlib.h> +++ |+#include <string.h> 6 | main.c:115:5: warning: incompatible implicit declaration of built-in function 'memcpy' [-Wbuiltin-declaration-mismatch] 115 | memcpy(tmp, matrix[i], cols * sizeof(int)); | ^~~~~~ main.c:115:5: note: include '<string.h>' or provide a declaration of 'memcpy' main.c: At top level: main.c:120:6: warning: conflicting types for 'swap_ints'; have 'void(int *, int *)' 120 | void swap_ints(int* a, int* b) { | ^~~~~~~~~ main.c:34:13: note: previous implicit declaration of 'swap_ints' with type 'void(int *, int *)' 34 | swap_ints(&used_for_row[col], &used_for_row[other]); | ^~~~~~~~~ main.c:126:6: error: conflicting types for 'find_nonzeroes'; have 'int *(int **, int, int, int)' 126 | int* find_nonzeroes(int** matrix, int col, int rows, int cols) { | ^~~~~~~~~~~~~~ main.c:49:23: note: previous implicit declaration of 'find_nonzeroes' with type 'int()' 49 | int* others = find_nonzeroes(matrix, col + extra, rows, cols); | ^~~~~~~~~~~~~~ main.c: In function 'subtract_rows_mod_PH': main.c:167:25: error: 'cols' undeclared (first use in this function) 167 | for (int i = 0; i < cols; i++) { | ^~~~ main.sh: line 2: ./a.out: No such file or directory

Substring Evaluation

Testing if the previous output contains the string All tests passed: False