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 the C translation of the function. Note that I've included helper functions for set operations since C doesn't have built-in set data structures: 

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#include <stdlib.h>
#include <string.h>

// Helper struct for set implementation
typedef struct {
    int* elements;
    int size;
    int capacity;
} IntSet;

// Helper functions for set operations
IntSet* createSet(int initial_capacity) {
    IntSet* set = (IntSet*)malloc(sizeof(IntSet));
    set->elements = (int*)malloc(initial_capacity * sizeof(int));
    set->size = 0;
    set->capacity = initial_capacity;
    return set;
}

void addToSet(IntSet* set, int value) {
    // Check if value already exists
    for (int i = 0; i < set->size; i++) {
        if (set->elements[i] == value) return;
    }
    
    // Resize if necessary
    if (set->size >= set->capacity) {
        set->capacity *= 2;
        set->elements = (int*)realloc(set->elements, set->capacity * sizeof(int));
    }
    
    set->elements[set->size++] = value;
}

void unionSets(IntSet* dest, IntSet* src) {
    for (int i = 0; i < src->size; i++) {
        addToSet(dest, src->elements[i]);
    }
}

// Main RREF function
IntSet** rref(int** matrix, int rows, int cols, int graphlen) {
    const int PH = 16;
    
    // Initialize used_for_row
    IntSet** used_for_row = (IntSet**)malloc(rows * sizeof(IntSet*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = createSet(10);  // Initial capacity of 10
        addToSet(used_for_row[i], i);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    int col = 0;
    int extra = 0;
    
    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Find non-zero element in column
            int other = -1;
            for (int i = rows - 1; i >= 0; i--) {
                if (matrix[i][col + extra] != 0) {
                    other = i;
                    break;
                }
            }
            
            if (other == -1 || other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            IntSet* temp_set = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_set;
        }
        
        // Normalize pivot row
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            if (pivot != 1 && pivot != PH - 1) {
                // Error handling could be added here
                continue;
            }
        } else {
            if (pivot != 2 && pivot != PH - 2) {
                // Error handling could be added here
                continue;
            }
            pivot /= 2;
        }
        
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            
            if (matrix[i][col + extra] != 0) {
                unionSets(used_for_row[i], used_for_row[col]);
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    return used_for_row;
}
This implementation: 1. Uses a simple IntSet struct to simulate Python's set functionality 2. Implements basic set operations (add, union) 3. Follows the same logic as the Python code for the RREF algorithm 4. Handles modular arithmetic consistently Note that: - The caller is responsible for freeing the returned used_for_row array and its contents - Error handling is minimal compared to the Python version - The implementation assumes all inputs are valid - Some Python numpy operations are translated to explicit loops - The set implementation is simplified and could be optimized further if needed To use the returned sets, you'll need to access the elements and size members of each IntSet structure. The elements are stored in sorted order as they're added. Remember to free the memory when you're done: 
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for (int i = 0; i < rows; i++) {
    free(used_for_row[i]->elements);
    free(used_for_row[i]);
}
free(used_for_row);

Extract Code

I extracted the following code from that output: 

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#include <stdlib.h>
#include <string.h>

typedef struct {
    int* elements;
    int size;
    int capacity;
} IntSet;

IntSet* createSet(int initial_capacity) {
    IntSet* set = (IntSet*)malloc(sizeof(IntSet));
    set->elements = (int*)malloc(initial_capacity * sizeof(int));
    set->size = 0;
    set->capacity = initial_capacity;
    return set;
}

void addToSet(IntSet* set, int value) {
    for (int i = 0; i < set->size; i++) {
        if (set->elements[i] == value) return;
    }
    
    if (set->size >= set->capacity) {
        set->capacity *= 2;
        set->elements = (int*)realloc(set->elements, set->capacity * sizeof(int));
    }
    
    set->elements[set->size++] = value;
}

void unionSets(IntSet* dest, IntSet* src) {
    for (int i = 0; i < src->size; i++) {
        addToSet(dest, src->elements[i]); 
    }
}

IntSet** rref(int** matrix, int rows, int cols, int graphlen) {
    const int PH = 16;
    
    IntSet** used_for_row = (IntSet**)malloc(rows * sizeof(IntSet*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = createSet(10);
        addToSet(used_for_row[i], i);
    }
    
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    int col = 0;
    int extra = 0;
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            int other = -1;
            for (int i = rows - 1; i >= 0; i--) {
                if (matrix[i][col + extra] != 0) {
                    other = i;
                    break;
                }
            }
            
            if (other == -1 || other < col) {
                extra++;
                continue;
            }
            
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            IntSet* temp_set = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_set;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            if (pivot != 1 && pivot != PH - 1) {
                continue;
            }
        } else {
            if (pivot != 2 && pivot != PH - 2) {
                continue;
            }
            pivot /= 2;
        }
        
        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;
            
            if (matrix[i][col + extra] != 0) {
                unionSets(used_for_row[i], used_for_row[col]);
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    return used_for_row;
}

Run Code Interpreter

Running the following program: 

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#include <stdlib.h>
#include <string.h>

typedef struct {
    int* elements;
    int size;
    int capacity;
} IntSet;

IntSet* createSet(int initial_capacity) {
    IntSet* set = (IntSet*)malloc(sizeof(IntSet));
    set->elements = (int*)malloc(initial_capacity * sizeof(int));
    set->size = 0;
    set->capacity = initial_capacity;
    return set;
}

void addToSet(IntSet* set, int value) {
    for (int i = 0; i < set->size; i++) {
        if (set->elements[i] == value) return;
    }
    
    if (set->size >= set->capacity) {
        set->capacity *= 2;
        set->elements = (int*)realloc(set->elements, set->capacity * sizeof(int));
    }
    
    set->elements[set->size++] = value;
}

void unionSets(IntSet* dest, IntSet* src) {
    for (int i = 0; i < src->size; i++) {
        addToSet(dest, src->elements[i]); 
    }
}

IntSet** rref(int** matrix, int rows, int cols, int graphlen) {
    const int PH = 16;
    
    IntSet** used_for_row = (IntSet**)malloc(rows * sizeof(IntSet*));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = createSet(10);
        addToSet(used_for_row[i], i);
    }
    
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    int col = 0;
    int extra = 0;
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            int other = -1;
            for (int i = rows - 1; i >= 0; i--) {
                if (matrix[i][col + extra] != 0) {
                    other = i;
                    break;
                }
            }
            
            if (other == -1 || other < col) {
                extra++;
                continue;
            }
            
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            IntSet* temp_set = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_set;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            if (pivot != 1 && pivot != PH - 1) {
                continue;
            }
        } else {
            if (pivot != 2 && pivot != PH - 2) {
                continue;
            }
            pivot /= 2;
        }
        
        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;
            
            if (matrix[i][col + extra] != 0) {
                unionSets(used_for_row[i], used_for_row[col]);
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    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: Wrong answer; got -314318815 instead of 146. main.c: In function 'main': main.c:170:13: warning: initialization of 'int **' from incompatible pointer type 'IntSet **' [-Wincompatible-pointer-types] 170 | int** got = rref(arr, 39, 49, 37); | ^~~~

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 the C implementation of the RREF (Reduced Row Echelon Form) function: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to allocate a 2D array for used_for_row sets
int** allocate_used_for_row(int rows) {
    int** used = malloc(rows * sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used[i] = malloc(rows * sizeof(int));
        used[i][0] = 1;  // First element is the size of the set
        used[i][1] = i;  // Initialize with own index
    }
    return used;
}

// Helper function to merge sets
void merge_sets(int** used_for_row, int target, int source) {
    int* target_set = used_for_row[target];
    int* source_set = used_for_row[source];
    
    // Temporary array to store merged result
    int temp[100];  // Assuming maximum possible size
    int temp_size = 0;
    
    // Merge both sets
    int i = 1, j = 1;
    while (i <= target_set[0] && j <= source_set[0]) {
        if (target_set[i] < source_set[j]) {
            temp[temp_size++] = target_set[i++];
        } else if (target_set[i] > source_set[j]) {
            temp[temp_size++] = source_set[j++];
        } else {
            temp[temp_size++] = target_set[i++];
            j++;
        }
    }
    
    while (i <= target_set[0]) temp[temp_size++] = target_set[i++];
    while (j <= source_set[0]) temp[temp_size++] = source_set[j++];
    
    // Update target set
    target_set[0] = temp_size;
    for (int k = 0; k < temp_size; k++) {
        target_set[k + 1] = temp[k];
    }
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    int** used_for_row = allocate_used_for_row(rows);
    
    // Apply modulo PH to all elements
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Find non-zero element in column
            int other = -1;
            for (int i = rows - 1; i >= 0; i--) {
                if (matrix[i][col + extra] != 0) {
                    other = i;
                    break;
                }
            }
            
            if (other == -1 || other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;
        }
        
        // Normalize pivot row
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            pivot = (pivot == 1 || pivot == PH - 1) ? pivot : 1;
        } else {
            pivot = pivot / 2;
        }
        
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            
            if (matrix[i][col + extra] != 0) {
                merge_sets(used_for_row, i, col);
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    return used_for_row;
}
This implementation: 1. Uses a helper function `allocate_used_for_row` to create and initialize the sets 2. Uses a helper function `merge_sets` to merge two sets when needed 3. Follows the same logic as the Python version but with explicit memory management 4. Stores sets as arrays where the first element indicates the size of the set Key differences from the Python version: 1. Manual memory management 2. Explicit modulo operations with proper handling of negative numbers 3. Set operations implemented using sorted arrays 4. No numpy operations, everything done with explicit loops Note that the caller is responsible for freeing the returned `used_for_row` array and its contents when they're no longer needed.

Extract Code

I extracted the following code from that output: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to allocate a 2D array for used_for_row sets
int** allocate_used_for_row(int rows) {
    int** used = malloc(rows * sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used[i] = malloc(rows * sizeof(int));
        used[i][0] = 1;  // First element is the size of the set
        used[i][1] = i;  // Initialize with own index
    }
    return used;
}

// Helper function to merge sets
void merge_sets(int** used_for_row, int target, int source) {
    int* target_set = used_for_row[target];
    int* source_set = used_for_row[source];
    
    // Temporary array to store merged result
    int temp[100];  // Assuming maximum possible size
    int temp_size = 0;
    
    // Merge both sets
    int i = 1, j = 1;
    while (i <= target_set[0] && j <= source_set[0]) {
        if (target_set[i] < source_set[j]) {
            temp[temp_size++] = target_set[i++];
        } else if (target_set[i] > source_set[j]) {
            temp[temp_size++] = source_set[j++];
        } else {
            temp[temp_size++] = target_set[i++];
            j++;
        }
    }
    
    while (i <= target_set[0]) temp[temp_size++] = target_set[i++];
    while (j <= source_set[0]) temp[temp_size++] = source_set[j++];
    
    // Update target set
    target_set[0] = temp_size;
    for (int k = 0; k < temp_size; k++) {
        target_set[k + 1] = temp[k];
    }
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    int** used_for_row = allocate_used_for_row(rows);
    
    // Apply modulo PH to all elements
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Find non-zero element in column
            int other = -1;
            for (int i = rows - 1; i >= 0; i--) {
                if (matrix[i][col + extra] != 0) {
                    other = i;
                    break;
                }
            }
            
            if (other == -1 || other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;
        }
        
        // Normalize pivot row
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            pivot = (pivot == 1 || pivot == PH - 1) ? pivot : 1;
        } else {
            pivot = pivot / 2;
        }
        
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            
            if (matrix[i][col + extra] != 0) {
                merge_sets(used_for_row, i, col);
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    return used_for_row;
}

Run Code Interpreter

Running the following program: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to allocate a 2D array for used_for_row sets
int** allocate_used_for_row(int rows) {
    int** used = malloc(rows * sizeof(int*));
    for (int i = 0; i < rows; i++) {
        used[i] = malloc(rows * sizeof(int));
        used[i][0] = 1;  // First element is the size of the set
        used[i][1] = i;  // Initialize with own index
    }
    return used;
}

// Helper function to merge sets
void merge_sets(int** used_for_row, int target, int source) {
    int* target_set = used_for_row[target];
    int* source_set = used_for_row[source];
    
    // Temporary array to store merged result
    int temp[100];  // Assuming maximum possible size
    int temp_size = 0;
    
    // Merge both sets
    int i = 1, j = 1;
    while (i <= target_set[0] && j <= source_set[0]) {
        if (target_set[i] < source_set[j]) {
            temp[temp_size++] = target_set[i++];
        } else if (target_set[i] > source_set[j]) {
            temp[temp_size++] = source_set[j++];
        } else {
            temp[temp_size++] = target_set[i++];
            j++;
        }
    }
    
    while (i <= target_set[0]) temp[temp_size++] = target_set[i++];
    while (j <= source_set[0]) temp[temp_size++] = source_set[j++];
    
    // Update target set
    target_set[0] = temp_size;
    for (int k = 0; k < temp_size; k++) {
        target_set[k + 1] = temp[k];
    }
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    int** used_for_row = allocate_used_for_row(rows);
    
    // Apply modulo PH to all elements
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Find non-zero element in column
            int other = -1;
            for (int i = rows - 1; i >= 0; i--) {
                if (matrix[i][col + extra] != 0) {
                    other = i;
                    break;
                }
            }
            
            if (other == -1 || other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;
        }
        
        // Normalize pivot row
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            pivot = (pivot == 1 || pivot == PH - 1) ? pivot : 1;
        } else {
            pivot = pivot / 2;
        }
        
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            
            if (matrix[i][col + extra] != 0) {
                merge_sets(used_for_row, i, col);
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    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: Wrong answer; got 115 instead of 146.

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 the C implementation of the RREF function. Note that I've included necessary helper functions for set operations: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to create a new set
int* create_set(int initial_value, int* size) {
    int* set = malloc(sizeof(int));
    set[0] = initial_value;
    *size = 1;
    return set;
}

// Helper function to union two sets
int* set_union(int* set1, int size1, int* set2, int size2, int* new_size) {
    int* result = malloc((size1 + size2) * sizeof(int));
    int i = 0, j = 0, k = 0;
    
    while (i < size1 && j < size2) {
        if (set1[i] < set2[j]) {
            result[k++] = set1[i++];
        } else if (set1[i] > set2[j]) {
            result[k++] = set2[j++];
        } else {
            result[k++] = set1[i++];
            j++;
        }
    }
    
    while (i < size1) result[k++] = set1[i++];
    while (j < size2) result[k++] = set2[j++];
    
    *new_size = k;
    return result;
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    
    // Initialize used_for_row
    int** used_for_row = malloc(rows * sizeof(int*));
    int* set_sizes = malloc(rows * sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set(i, &set_sizes[i]);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            // Check if column is all zeros
            int all_zeros = 1;
            int last_nonzero = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zeros = 0;
                    last_nonzero = i;
                }
            }
            
            if (all_zeros) {
                extra++;
                continue;
            }
            
            if (last_nonzero < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[last_nonzero];
            matrix[last_nonzero] = temp_row;
            
            int* temp_used = used_for_row[col];
            int temp_size = set_sizes[col];
            used_for_row[col] = used_for_row[last_nonzero];
            set_sizes[col] = set_sizes[last_nonzero];
            used_for_row[last_nonzero] = temp_used;
            set_sizes[last_nonzero] = temp_size;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert pivot is 1 or PH-1
        } else {
            // Assert pivot is 2 or PH-2
            pivot /= 2;
        }
        
        // Multiply row by pivot inverse
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] != 0) {
                // Union sets
                int new_size;
                int* new_set = set_union(used_for_row[i], set_sizes[i], 
                                       used_for_row[col], set_sizes[col], &new_size);
                free(used_for_row[i]);
                used_for_row[i] = new_set;
                set_sizes[i] = new_size;
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - matrix[col][j] * factor) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    free(set_sizes);
    return used_for_row;
}
This implementation: 1. Uses dynamic memory allocation for the sets and matrix operations 2. Implements set operations using sorted arrays 3. Handles modular arithmetic consistently 4. Maintains the same logic as the Python version Key differences from the Python version: 1. Manual memory management with malloc/free 2. Explicit set operations instead of Python's built-in set type 3. Manual array operations instead of NumPy operations 4. More explicit loop control and array indexing Note that this implementation assumes: 1. The input matrix is properly allocated and initialized 2. The caller is responsible for freeing the returned used_for_row array 3. The matrix dimensions are valid The returned used_for_row is an array of sorted integer arrays representing the sets from the original implementation.

Extract Code

I extracted the following code from that output: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to create a new set
int* create_set(int initial_value, int* size) {
    int* set = malloc(sizeof(int));
    set[0] = initial_value;
    *size = 1;
    return set;
}

// Helper function to union two sets
int* set_union(int* set1, int size1, int* set2, int size2, int* new_size) {
    int* result = malloc((size1 + size2) * sizeof(int));
    int i = 0, j = 0, k = 0;
    
    while (i < size1 && j < size2) {
        if (set1[i] < set2[j]) {
            result[k++] = set1[i++];
        } else if (set1[i] > set2[j]) {
            result[k++] = set2[j++];
        } else {
            result[k++] = set1[i++];
            j++;
        }
    }
    
    while (i < size1) result[k++] = set1[i++];
    while (j < size2) result[k++] = set2[j++];
    
    *new_size = k;
    return result;
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    
    // Initialize used_for_row
    int** used_for_row = malloc(rows * sizeof(int*));
    int* set_sizes = malloc(rows * sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set(i, &set_sizes[i]);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            // Check if column is all zeros
            int all_zeros = 1;
            int last_nonzero = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zeros = 0;
                    last_nonzero = i;
                }
            }
            
            if (all_zeros) {
                extra++;
                continue;
            }
            
            if (last_nonzero < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[last_nonzero];
            matrix[last_nonzero] = temp_row;
            
            int* temp_used = used_for_row[col];
            int temp_size = set_sizes[col];
            used_for_row[col] = used_for_row[last_nonzero];
            set_sizes[col] = set_sizes[last_nonzero];
            used_for_row[last_nonzero] = temp_used;
            set_sizes[last_nonzero] = temp_size;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert pivot is 1 or PH-1
        } else {
            // Assert pivot is 2 or PH-2
            pivot /= 2;
        }
        
        // Multiply row by pivot inverse
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] != 0) {
                // Union sets
                int new_size;
                int* new_set = set_union(used_for_row[i], set_sizes[i], 
                                       used_for_row[col], set_sizes[col], &new_size);
                free(used_for_row[i]);
                used_for_row[i] = new_set;
                set_sizes[i] = new_size;
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - matrix[col][j] * factor) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    free(set_sizes);
    return used_for_row;
}

Run Code Interpreter

Running the following program: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to create a new set
int* create_set(int initial_value, int* size) {
    int* set = malloc(sizeof(int));
    set[0] = initial_value;
    *size = 1;
    return set;
}

// Helper function to union two sets
int* set_union(int* set1, int size1, int* set2, int size2, int* new_size) {
    int* result = malloc((size1 + size2) * sizeof(int));
    int i = 0, j = 0, k = 0;
    
    while (i < size1 && j < size2) {
        if (set1[i] < set2[j]) {
            result[k++] = set1[i++];
        } else if (set1[i] > set2[j]) {
            result[k++] = set2[j++];
        } else {
            result[k++] = set1[i++];
            j++;
        }
    }
    
    while (i < size1) result[k++] = set1[i++];
    while (j < size2) result[k++] = set2[j++];
    
    *new_size = k;
    return result;
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    
    // Initialize used_for_row
    int** used_for_row = malloc(rows * sizeof(int*));
    int* set_sizes = malloc(rows * sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set(i, &set_sizes[i]);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            // Check if column is all zeros
            int all_zeros = 1;
            int last_nonzero = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zeros = 0;
                    last_nonzero = i;
                }
            }
            
            if (all_zeros) {
                extra++;
                continue;
            }
            
            if (last_nonzero < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[last_nonzero];
            matrix[last_nonzero] = temp_row;
            
            int* temp_used = used_for_row[col];
            int temp_size = set_sizes[col];
            used_for_row[col] = used_for_row[last_nonzero];
            set_sizes[col] = set_sizes[last_nonzero];
            used_for_row[last_nonzero] = temp_used;
            set_sizes[last_nonzero] = temp_size;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert pivot is 1 or PH-1
        } else {
            // Assert pivot is 2 or PH-2
            pivot /= 2;
        }
        
        // Multiply row by pivot inverse
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] != 0) {
                // Union sets
                int new_size;
                int* new_set = set_union(used_for_row[i], set_sizes[i], 
                                       used_for_row[col], set_sizes[col], &new_size);
                free(used_for_row[i]);
                used_for_row[i] = new_set;
                set_sizes[i] = new_size;
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - matrix[col][j] * factor) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    free(set_sizes);
    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: All tests passed

Substring Evaluation

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

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 the C version of the function. Note that I've included helper functions for set operations since C doesn't have built-in set data structures: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to create a set
int* create_set(int initial_value, int* size) {
    int* set = (int*)malloc(sizeof(int));
    set[0] = initial_value;
    *size = 1;
    return set;
}

// Helper function to merge sets
int* merge_sets(int* set1, int size1, int* set2, int size2, int* new_size) {
    int* merged = (int*)malloc((size1 + size2) * sizeof(int));
    int i = 0, j = 0, k = 0;
    
    while (i < size1 && j < size2) {
        if (set1[i] < set2[j])
            merged[k++] = set1[i++];
        else if (set1[i] > set2[j])
            merged[k++] = set2[j++];
        else {
            merged[k++] = set1[i++];
            j++;
        }
    }
    
    while (i < size1)
        merged[k++] = set1[i++];
    while (j < size2)
        merged[k++] = set2[j++];
    
    *new_size = k;
    return merged;
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    
    // Initialize used_for_row
    int** used_for_row = (int**)malloc(rows * sizeof(int*));
    int* set_sizes = (int*)malloc(rows * sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set(i, &set_sizes[i]);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            // Check if column is all zeros
            int all_zeros = 1;
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zeros = 0;
                    other = i;
                }
            }
            
            if (all_zeros) {
                extra++;
                continue;
            }
            
            if (other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;
            
            int temp_size = set_sizes[col];
            set_sizes[col] = set_sizes[other];
            set_sizes[other] = temp_size;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert pivot is 1 or PH-1
        } else {
            // Assert pivot is 2 or PH-2
            pivot /= 2;
        }
        
        // Multiply row by inverse of pivot
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] != 0) {
                // Merge sets
                int new_size;
                int* new_set = merge_sets(used_for_row[i], set_sizes[i],
                                        used_for_row[col], set_sizes[col], &new_size);
                free(used_for_row[i]);
                used_for_row[i] = new_set;
                set_sizes[i] = new_size;
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    free(set_sizes);
    return used_for_row;
}
This C implementation: 1. Uses dynamic memory allocation for the sets and matrices 2. Implements basic set operations (creation and merging) 3. Handles the modular arithmetic 4. Maintains the same logic as the Python version Note that: - The caller is responsible for freeing the returned `used_for_row` array and its contents - Some assertions from the Python code are commented out as they would need additional error handling in C - The function assumes all input parameters are valid - The modular arithmetic is handled with extra care to ensure positive remainders To use this function, make sure to allocate the input matrix properly and free the returned array when done: 
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// Example usage:
int rows = 3, cols = 4;
int** matrix = malloc(rows * sizeof(int*));
for (int i = 0; i < rows; i++) {
    matrix[i] = malloc(cols * sizeof(int));
}

int** result = rref(matrix, rows, cols, graphlen);

// Don't forget to free memory when done
for (int i = 0; i < rows; i++) {
    free(result[i]);
}
free(result);

Extract Code

I extracted the following code from that output: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to create a set
int* create_set(int initial_value, int* size) {
    int* set = (int*)malloc(sizeof(int));
    set[0] = initial_value;
    *size = 1;
    return set;
}

// Helper function to merge sets 
int* merge_sets(int* set1, int size1, int* set2, int size2, int* new_size) {
    int* merged = (int*)malloc((size1 + size2) * sizeof(int));
    int i = 0, j = 0, k = 0;
    
    while (i < size1 && j < size2) {
        if (set1[i] < set2[j])
            merged[k++] = set1[i++];
        else if (set1[i] > set2[j])
            merged[k++] = set2[j++];
        else {
            merged[k++] = set1[i++];
            j++;
        }
    }
    
    while (i < size1)
        merged[k++] = set1[i++];
    while (j < size2)
        merged[k++] = set2[j++];
    
    *new_size = k;
    return merged;
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    
    // Initialize used_for_row
    int** used_for_row = (int**)malloc(rows * sizeof(int*));
    int* set_sizes = (int*)malloc(rows * sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set(i, &set_sizes[i]);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            // Check if column is all zeros
            int all_zeros = 1;
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zeros = 0;
                    other = i;
                }
            }
            
            if (all_zeros) {
                extra++;
                continue;
            }
            
            if (other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;
            
            int temp_size = set_sizes[col];
            set_sizes[col] = set_sizes[other];
            set_sizes[other] = temp_size;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert pivot is 1 or PH-1
        } else {
            // Assert pivot is 2 or PH-2
            pivot /= 2;
        }
        
        // Multiply row by inverse of pivot
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] != 0) {
                // Merge sets
                int new_size;
                int* new_set = merge_sets(used_for_row[i], set_sizes[i],
                                        used_for_row[col], set_sizes[col], &new_size);
                free(used_for_row[i]);
                used_for_row[i] = new_set;
                set_sizes[i] = new_size;
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    free(set_sizes);
    return used_for_row;
}

Run Code Interpreter

Running the following program: 

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#include <stdlib.h>
#include <string.h>

#define PH 16

// Helper function to create a set
int* create_set(int initial_value, int* size) {
    int* set = (int*)malloc(sizeof(int));
    set[0] = initial_value;
    *size = 1;
    return set;
}

// Helper function to merge sets 
int* merge_sets(int* set1, int size1, int* set2, int size2, int* new_size) {
    int* merged = (int*)malloc((size1 + size2) * sizeof(int));
    int i = 0, j = 0, k = 0;
    
    while (i < size1 && j < size2) {
        if (set1[i] < set2[j])
            merged[k++] = set1[i++];
        else if (set1[i] > set2[j])
            merged[k++] = set2[j++];
        else {
            merged[k++] = set1[i++];
            j++;
        }
    }
    
    while (i < size1)
        merged[k++] = set1[i++];
    while (j < size2)
        merged[k++] = set2[j++];
    
    *new_size = k;
    return merged;
}

int** rref(int** matrix, int rows, int cols, int graphlen) {
    int extra = 0;
    int col = 0;
    
    // Initialize used_for_row
    int** used_for_row = (int**)malloc(rows * sizeof(int*));
    int* set_sizes = (int*)malloc(rows * sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = create_set(i, &set_sizes[i]);
    }
    
    // Apply modulo PH to matrix
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < cols; j++) {
            matrix[i][j] = ((matrix[i][j] % PH) + PH) % PH;
        }
    }
    
    while (col + extra < cols - 1 && col < rows) {
        if (matrix[col][col + extra] == 0) {
            // Check if column is all zeros
            int all_zeros = 1;
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zeros = 0;
                    other = i;
                }
            }
            
            if (all_zeros) {
                extra++;
                continue;
            }
            
            if (other < col) {
                extra++;
                continue;
            }
            
            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;
            
            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;
            
            int temp_size = set_sizes[col];
            set_sizes[col] = set_sizes[other];
            set_sizes[other] = temp_size;
        }
        
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert pivot is 1 or PH-1
        } else {
            // Assert pivot is 2 or PH-2
            pivot /= 2;
        }
        
        // Multiply row by inverse of pivot
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }
        
        // Eliminate in other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] != 0) {
                // Merge sets
                int new_size;
                int* new_set = merge_sets(used_for_row[i], set_sizes[i],
                                        used_for_row[col], set_sizes[col], &new_size);
                free(used_for_row[i]);
                used_for_row[i] = new_set;
                set_sizes[i] = new_size;
                
                if (col < graphlen) {
                    int factor = matrix[i][col + extra];
                    for (int j = 0; j < cols; j++) {
                        matrix[i][j] = ((matrix[i][j] - factor * matrix[col][j]) % PH + 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) % PH;
                        }
                    }
                }
            }
        }
        
        col++;
    }
    
    free(set_sizes);
    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: All tests passed

Substring Evaluation

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

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 the C version of the function: 

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#include <stdlib.h>
#include <string.h>

int** rref(int** matrix, int rows, int cols, int graphlen) {
    const int PH = 16;
    int extra = 0;
    int col = 0;

    // Initialize used_for_row
    int** used_for_row = (int**)malloc(rows * sizeof(int*));
    int* sizes = (int*)calloc(rows, sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = (int*)malloc(rows * sizeof(int));
        used_for_row[i][0] = i;
        sizes[i] = 1;
    }

    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Check if entire column is zero
            int all_zero = 1;
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zero = 0;
                    other = i;
                }
            }

            if (all_zero) {
                extra++;
                continue;
            }

            if (other < col) {
                extra++;
                continue;
            }

            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;

            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;

            int temp_size = sizes[col];
            sizes[col] = sizes[other];
            sizes[other] = temp_size;
        }

        // Process pivot
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert abs(pivot) == 1 or abs(pivot) == PH-1
            pivot = (pivot + PH) % PH;  // Ensure positive
        } else {
            // Assert abs(pivot) == 2 or abs(pivot) == PH-2
            pivot /= 2;
        }

        // Multiply row by pivot inverse
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }

        // Process other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] == 0) continue;

            // Merge used_for_row sets
            int new_size = sizes[i];
            for (int k = 0; k < sizes[col]; k++) {
                int val = used_for_row[col][k];
                int found = 0;
                for (int m = 0; m < sizes[i]; m++) {
                    if (used_for_row[i][m] == val) {
                        found = 1;
                        break;
                    }
                }
                if (!found) {
                    used_for_row[i][new_size++] = val;
                }
            }
            sizes[i] = new_size;

            // Row operations
            if (col < graphlen) {
                int factor = matrix[i][col + extra];
                for (int j = 0; j < cols; j++) {
                    matrix[i][j] = (matrix[i][j] - factor * matrix[col][j]) % PH;
                    if (matrix[i][j] < 0) matrix[i][j] += 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;
                        if (matrix[i][j] < 0) matrix[i][j] += PH;
                    }
                }
            }
        }

        col++;
    }

    // Sort each row of used_for_row
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < sizes[i] - 1; j++) {
            for (int k = 0; k < sizes[i] - j - 1; k++) {
                if (used_for_row[i][k] > used_for_row[i][k + 1]) {
                    int temp = used_for_row[i][k];
                    used_for_row[i][k] = used_for_row[i][k + 1];
                    used_for_row[i][k + 1] = temp;
                }
            }
        }
    }

    free(sizes);
    return used_for_row;
}
This C implementation follows the same logic as the Python version but with some key differences due to C's limitations: 1. Memory management is manual using malloc/free 2. Sets are implemented as sorted arrays 3. The function returns the used_for_row array which needs to be freed by the caller 4. Matrix operations are implemented explicitly rather than using numpy functions 5. Modulo operations need to handle negative numbers explicitly The caller should free the returned array and its contents when done: 
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// To free the result:
for (int i = 0; i < rows; i++) {
    free(used_for_row[i]);
}
free(used_for_row);
Note that this implementation assumes that all matrix values are integers and that the input matrix is properly formatted. The function performs row operations to get the matrix into reduced row echelon form while tracking which rows have been used to eliminate entries in other rows.

Extract Code

I extracted the following code from that output: 

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#include <stdlib.h>
#include <string.h>

int** rref(int** matrix, int rows, int cols, int graphlen) {
    const int PH = 16;
    int extra = 0;
    int col = 0;

    // Initialize used_for_row
    int** used_for_row = (int**)malloc(rows * sizeof(int*));
    int* sizes = (int*)calloc(rows, sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = (int*)malloc(rows * sizeof(int));
        used_for_row[i][0] = i;
        sizes[i] = 1;
    }

    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Check if entire column is zero
            int all_zero = 1;
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zero = 0;
                    other = i;
                }
            }

            if (all_zero) {
                extra++;
                continue;
            }

            if (other < col) {
                extra++;
                continue;
            }

            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;

            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;

            int temp_size = sizes[col];
            sizes[col] = sizes[other];
            sizes[other] = temp_size;
        }

        // Process pivot
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert abs(pivot) == 1 or abs(pivot) == PH-1
            pivot = (pivot + PH) % PH;  // Ensure positive
        } else {
            // Assert abs(pivot) == 2 or abs(pivot) == PH-2
            pivot /= 2;
        }

        // Multiply row by pivot inverse
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }

        // Process other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] == 0) continue;

            // Merge used_for_row sets
            int new_size = sizes[i];
            for (int k = 0; k < sizes[col]; k++) {
                int val = used_for_row[col][k];
                int found = 0;
                for (int m = 0; m < sizes[i]; m++) {
                    if (used_for_row[i][m] == val) {
                        found = 1;
                        break;
                    }
                }
                if (!found) {
                    used_for_row[i][new_size++] = val;
                }
            }
            sizes[i] = new_size;

            // Row operations
            if (col < graphlen) {
                int factor = matrix[i][col + extra];
                for (int j = 0; j < cols; j++) {
                    matrix[i][j] = (matrix[i][j] - factor * matrix[col][j]) % PH;
                    if (matrix[i][j] < 0) matrix[i][j] += 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;
                        if (matrix[i][j] < 0) matrix[i][j] += PH;
                    }
                }
            }
        }

        col++;
    }

    // Sort each row of used_for_row
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < sizes[i] - 1; j++) {
            for (int k = 0; k < sizes[i] - j - 1; k++) {
                if (used_for_row[i][k] > used_for_row[i][k + 1]) {
                    int temp = used_for_row[i][k];
                    used_for_row[i][k] = used_for_row[i][k + 1];
                    used_for_row[i][k + 1] = temp;
                }
            }
        }
    }

    free(sizes);
    return used_for_row;
}

Run Code Interpreter

Running the following program: 

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#include <stdlib.h>
#include <string.h>

int** rref(int** matrix, int rows, int cols, int graphlen) {
    const int PH = 16;
    int extra = 0;
    int col = 0;

    // Initialize used_for_row
    int** used_for_row = (int**)malloc(rows * sizeof(int*));
    int* sizes = (int*)calloc(rows, sizeof(int));
    for (int i = 0; i < rows; i++) {
        used_for_row[i] = (int*)malloc(rows * sizeof(int));
        used_for_row[i][0] = i;
        sizes[i] = 1;
    }

    while (col + extra < cols - 1 && col < rows) {
        // Check if pivot is zero
        if (matrix[col][col + extra] == 0) {
            // Check if entire column is zero
            int all_zero = 1;
            int other = -1;
            for (int i = 0; i < rows; i++) {
                if (matrix[i][col + extra] != 0) {
                    all_zero = 0;
                    other = i;
                }
            }

            if (all_zero) {
                extra++;
                continue;
            }

            if (other < col) {
                extra++;
                continue;
            }

            // Swap rows
            int* temp_row = matrix[col];
            matrix[col] = matrix[other];
            matrix[other] = temp_row;

            int* temp_used = used_for_row[col];
            used_for_row[col] = used_for_row[other];
            used_for_row[other] = temp_used;

            int temp_size = sizes[col];
            sizes[col] = sizes[other];
            sizes[other] = temp_size;
        }

        // Process pivot
        int pivot = matrix[col][col + extra];
        if (col + extra < graphlen) {
            // Assert abs(pivot) == 1 or abs(pivot) == PH-1
            pivot = (pivot + PH) % PH;  // Ensure positive
        } else {
            // Assert abs(pivot) == 2 or abs(pivot) == PH-2
            pivot /= 2;
        }

        // Multiply row by pivot inverse
        for (int j = 0; j < cols; j++) {
            matrix[col][j] = (matrix[col][j] * pivot) % PH;
        }

        // Process other rows
        for (int i = 0; i < rows; i++) {
            if (i == col) continue;
            if (matrix[i][col + extra] == 0) continue;

            // Merge used_for_row sets
            int new_size = sizes[i];
            for (int k = 0; k < sizes[col]; k++) {
                int val = used_for_row[col][k];
                int found = 0;
                for (int m = 0; m < sizes[i]; m++) {
                    if (used_for_row[i][m] == val) {
                        found = 1;
                        break;
                    }
                }
                if (!found) {
                    used_for_row[i][new_size++] = val;
                }
            }
            sizes[i] = new_size;

            // Row operations
            if (col < graphlen) {
                int factor = matrix[i][col + extra];
                for (int j = 0; j < cols; j++) {
                    matrix[i][j] = (matrix[i][j] - factor * matrix[col][j]) % PH;
                    if (matrix[i][j] < 0) matrix[i][j] += 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;
                        if (matrix[i][j] < 0) matrix[i][j] += PH;
                    }
                }
            }
        }

        col++;
    }

    // Sort each row of used_for_row
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < sizes[i] - 1; j++) {
            for (int k = 0; k < sizes[i] - j - 1; k++) {
                if (used_for_row[i][k] > used_for_row[i][k + 1]) {
                    int temp = used_for_row[i][k];
                    used_for_row[i][k] = used_for_row[i][k + 1];
                    used_for_row[i][k + 1] = temp;
                }
            }
        }
    }

    free(sizes);
    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: All tests passed

Substring Evaluation

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