Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Certainly! Below is an implementation of the Levenshtein distance algorithm using Numba, a just-in-time compiler for Python that can greatly speed up the execution of code that uses NumPy arrays. This implementation specifically takes two 1D NumPy arrays of integers as input. The cost of an insertion or deletion is 1, and the cost of a substitution (character swap) is set to 2, as per your request. To use this code, you need to have both Numba and NumPy installed in your Python environment. You can install these packages using pip if you haven't done so already:
1 | pip install numba numpy |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | from numba import jit import numpy as np @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) len_arr2 = len(arr2) # Initialize the distance matrix dist = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): dist[i, 0] = i for j in range(len_arr2 + 1): dist[0, j] = j for i in range(1, len_arr1 + 1): for j in range(1, len_arr2 + 1): cost = 0 if arr1[i-1] == arr2[j-1] else 2 # Substitution cost is 2 dist[i, j] = min(dist[i-1, j] + 1, # Deletion dist[i, j-1] + 1, # Insertion dist[i-1, j-1] + cost) # Substitution return dist[len_arr1, len_arr2] # Example usage: arr1 = np.array([1, 2, 3, 4]) arr2 = np.array([1, 2, 4, 3]) print(levenshtein(arr1, arr2)) |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | from numba import jit import numpy as np @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) len_arr2 = len(arr2) # Initialize the distance matrix dist = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): dist[i, 0] = i for j in range(len_arr2 + 1): dist[0, j] = j for i in range(1, len_arr1 + 1): for j in range(1, len_arr2 + 1): cost = 0 if arr1[i-1] == arr2[j-1] else 2 # Substitution cost is 2 dist[i, j] = min(dist[i-1, j] + 1, # Deletion dist[i, j-1] + 1, # Insertion dist[i-1, j-1] + cost) # Substitution return dist[len_arr1, len_arr2] |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | from numba import jit import numpy as np @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) len_arr2 = len(arr2) # Initialize the distance matrix dist = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): dist[i, 0] = i for j in range(len_arr2 + 1): dist[0, j] = j for i in range(1, len_arr1 + 1): for j in range(1, len_arr2 + 1): cost = 0 if arr1[i-1] == arr2[j-1] else 2 # Substitution cost is 2 dist[i, j] = min(dist[i-1, j] + 1, # Deletion dist[i, j-1] + 1, # Insertion dist[i-1, j-1] + cost) # Substitution return dist[len_arr1, len_arr2] answer = levenshtein(np.array([3, 5, 2, 4, 8, 7]), np.array([3, 4, 2, 4, 8, 7, 9])) expected = 3 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Testing if the previous output contains the string njit
: False
Testing if the previous output contains the string nopython
: True
Testing if the previous output contains the string import numba
: False
Testing if the previous output contains the string from numba
: True
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
To create a Numba implementation of the Levenshtein distance that works with two NumPy arrays of integers and considers character swaps to have a cost of 2, you can follow the approach outlined below. This implementation will be designed to run in Nopython mode for efficiency. Numba is a Just-In-Time (JIT) compiler that translates a subset of Python and NumPy code into fast machine code. The following code example uses Numba's JIT decorator to compile the Python function into machine code when it's called with the specific argument types (in this case, NumPy arrays of integers) for the first time. The Levenshtein distance is a measure of the difference between two sequences. It is calculated as the minimum number of single-character edits (insertions, deletions, or substitutions) required to change one word into the other. In this implementation, we will modify the cost of substitutions (swaps) to be 2, as per your request.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | import numpy as np from numba import jit @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) len_arr2 = len(arr2) if len_arr1 == 0: return len_arr2 if len_arr2 == 0: return len_arr1 d = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): d[i, 0] = i for j in range(len_arr2 + 1): d[0, j] = j for i in range(1, len_arr1 + 1): for j in range(1, len_arr2 + 1): cost = 0 if arr1[i - 1] == arr2[j - 1] else 2 d[i, j] = min( d[i - 1, j] + 1, # deletion d[i, j - 1] + 1, # insertion d[i - 1, j - 1] + cost # substitution ) return d[len_arr1, len_arr2] # Example usage if __name__ == "__main__": arr1 = np.array([1, 2, 3, 4]) arr2 = np.array([1, 2, 4, 5]) print("Levenshtein distance:", levenshtein(arr1, arr2)) |
1 | pip install numba numpy |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | import numpy as np from numba import jit @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) len_arr2 = len(arr2) if len_arr1 == 0: return len_arr2 if len_arr2 == 0: return len_arr1 d = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): d[i, 0] = i for j in range(len_arr2 + 1): d[0, j] = j for i in range(1, len_arr1 + 1): for j in range(1, len_arr2 + 1): cost = 0 if arr1[i - 1] == arr2[j - 1] else 2 d[i, j] = min( d[i - 1, j] + 1, # deletion d[i, j - 1] + 1, # insertion d[i - 1, j - 1] + cost # substitution ) return d[len_arr1, len_arr2] |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | import numpy as np from numba import jit @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) len_arr2 = len(arr2) if len_arr1 == 0: return len_arr2 if len_arr2 == 0: return len_arr1 d = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): d[i, 0] = i for j in range(len_arr2 + 1): d[0, j] = j for i in range(1, len_arr1 + 1): for j in range(1, len_arr2 + 1): cost = 0 if arr1[i - 1] == arr2[j - 1] else 2 d[i, j] = min( d[i - 1, j] + 1, # deletion d[i, j - 1] + 1, # insertion d[i - 1, j - 1] + cost # substitution ) return d[len_arr1, len_arr2] answer = levenshtein(np.array([3, 5, 2, 4, 8, 7]), np.array([3, 4, 2, 4, 8, 7, 9])) expected = 3 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Testing if the previous output contains the string njit
: False
Testing if the previous output contains the string nopython
: True
Testing if the previous output contains the string import numba
: False
Testing if the previous output contains the string from numba
: True
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Sure, I'll provide you with a Numba implementation of the Levenshtein distance, designed to work with two NumPy arrays of integers. The Levenshtein distance is a measure of the difference between two sequences. In its most simple form, it calculates the minimum number of single-character edits (insertions, deletions, or substitutions) required to change one word into the other. In this implementation, a character swap will be considered as two operations (delete and insert, or two substitutions), since Numba's `@njit` decorator (nopython mode) will be used for performance, and direct swapping is not inherently part of the standard Levenshtein algorithm. First, ensure you have Numba and NumPy installed in your environment:
1 | pip install numba numpy |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | import numpy as np from numba import njit @njit def levenshtein(arr1, arr2): """ Compute the Levenshtein distance between two NumPy arrays of integers. """ m, n = len(arr1), len(arr2) # Initialize the matrix dp = np.zeros((m + 1, n + 1), dtype=np.int32) # Initialize source prefixes to transform into empty string by deletions: for i in range(1, m + 1): dp[i, 0] = i # Initialize target prefixes to be transformed from empty string by inserting: for j in range(1, n + 1): dp[0, j] = j # Compute Levenshtein distance for i in range(1, m + 1): for j in range(1, n + 1): deletion = dp[i - 1, j] + 1 insertion = dp[i, j - 1] + 1 substitution = dp[i - 1, j - 1] + (0 if arr1[i - 1] == arr2[j - 1] else 2) dp[i, j] = min(deletion, insertion, substitution) return dp[m, n] # Example usage: # Convert the sequences or strings to numpy arrays of integers, if not already arr1 = np.array([1, 2, 3, 4]) arr2 = np.array([1, 3, 4, 2]) distance = levenshtein(arr1, arr2) print("Levenshtein Distance:", distance) |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | import numpy as np from numba import njit @njit def levenshtein(arr1, arr2): """ Compute the Levenshtein distance between two NumPy arrays of integers. """ m, n = len(arr1), len(arr2) # Initialize the matrix dp = np.zeros((m + 1, n + 1), dtype=np.int32) # Initialize source prefixes to transform into empty string by deletions: for i in range(1, m + 1): dp[i, 0] = i # Initialize target prefixes to be transformed from empty string by inserting: for j in range(1, n + 1): dp[0, j] = j # Compute Levenshtein distance for i in range(1, m + 1): for j in range(1, n + 1): deletion = dp[i - 1, j] + 1 insertion = dp[i, j - 1] + 1 substitution = dp[i - 1, j - 1] + (0 if arr1[i - 1] == arr2[j - 1] else 2) dp[i, j] = min(deletion, insertion, substitution) return dp[m, n] |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | import numpy as np from numba import njit @njit def levenshtein(arr1, arr2): """ Compute the Levenshtein distance between two NumPy arrays of integers. """ m, n = len(arr1), len(arr2) # Initialize the matrix dp = np.zeros((m + 1, n + 1), dtype=np.int32) # Initialize source prefixes to transform into empty string by deletions: for i in range(1, m + 1): dp[i, 0] = i # Initialize target prefixes to be transformed from empty string by inserting: for j in range(1, n + 1): dp[0, j] = j # Compute Levenshtein distance for i in range(1, m + 1): for j in range(1, n + 1): deletion = dp[i - 1, j] + 1 insertion = dp[i, j - 1] + 1 substitution = dp[i - 1, j - 1] + (0 if arr1[i - 1] == arr2[j - 1] else 2) dp[i, j] = min(deletion, insertion, substitution) return dp[m, n] answer = levenshtein(np.array([3, 5, 2, 4, 8, 7]), np.array([3, 4, 2, 4, 8, 7, 9])) expected = 3 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Testing if the previous output contains the string njit
: True
Testing if the previous output contains the string nopython
: False
Testing if the previous output contains the string import numba
: False
Testing if the previous output contains the string from numba
: True
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Certainly! Below is an implementation of the Levenshtein distance algorithm, specifically tailored for dealing with numpy arrays of integers. The implementation is designed to work in nopython mode with Numba, a high-performance Just-In-Time compiler for Python. This version of the Levenshtein distance takes into account substitutions with a cost of 2, in line with your request. Insertions and deletions still have a cost of 1. First, ensure you have Numba and numpy installed in your environment:
1 | pip install numba numpy |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | import numpy as np from numba import njit @njit def levenshtein(arr1, arr2): """ Compute the Levenshtein distance between two numpy arrays of integers. In this implementation, character swaps (substitutions) have a cost of 2. Insertions and deletions have a cost of 1. """ len_arr1 = len(arr1) len_arr2 = len(arr2) # Initialize the matrix dp = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): for j in range(len_arr2 + 1): if i == 0: dp[i][j] = j # Deletion elif j == 0: dp[i][j] = i # Insertion else: cost = 0 if arr1[i-1] == arr2[j-1] else 2 dp[i][j] = min(dp[i-1][j] + 1, # Insertion dp[i][j-1] + 1, # Deletion dp[i-1][j-1] + cost) # Substitution return dp[len_arr1][len_arr2] # Example usage if __name__ == "__main__": arr1 = np.array([1, 2, 3], dtype=np.int32) arr2 = np.array([1, 3, 2], dtype=np.int32) distance = levenshtein(arr1, arr2) print(f"Levenshtein distance: {distance}") |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | import numpy as np from numba import njit @njit def levenshtein(arr1, arr2): """ Compute the Levenshtein distance between two numpy arrays of integers. In this implementation, character swaps (substitutions) have a cost of 2. Insertions and deletions have a cost of 1. """ len_arr1 = len(arr1) len_arr2 = len(arr2) # Initialize the matrix dp = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): for j in range(len_arr2 + 1): if i == 0: dp[i][j] = j # Deletion elif j == 0: dp[i][j] = i # Insertion else: cost = 0 if arr1[i-1] == arr2[j-1] else 2 dp[i][j] = min(dp[i-1][j] + 1, # Insertion dp[i][j-1] + 1, # Deletion dp[i-1][j-1] + cost) # Substitution return dp[len_arr1][len_arr2] |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | import numpy as np from numba import njit @njit def levenshtein(arr1, arr2): """ Compute the Levenshtein distance between two numpy arrays of integers. In this implementation, character swaps (substitutions) have a cost of 2. Insertions and deletions have a cost of 1. """ len_arr1 = len(arr1) len_arr2 = len(arr2) # Initialize the matrix dp = np.zeros((len_arr1 + 1, len_arr2 + 1), dtype=np.int32) for i in range(len_arr1 + 1): for j in range(len_arr2 + 1): if i == 0: dp[i][j] = j # Deletion elif j == 0: dp[i][j] = i # Insertion else: cost = 0 if arr1[i-1] == arr2[j-1] else 2 dp[i][j] = min(dp[i-1][j] + 1, # Insertion dp[i][j-1] + 1, # Deletion dp[i-1][j-1] + cost) # Substitution return dp[len_arr1][len_arr2] answer = levenshtein(np.array([3, 5, 2, 4, 8, 7]), np.array([3, 4, 2, 4, 8, 7, 9])) expected = 3 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Testing if the previous output contains the string njit
: True
Testing if the previous output contains the string nopython
: False
Testing if the previous output contains the string import numba
: False
Testing if the previous output contains the string from numba
: True
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
Write me a numba implementation of levensthin distance, taking two numpy int arrays. Call it levenshtein. Run it in nopython mode. Character swaps are cost 2.
To create a Numba implementation of the Levenshtein distance algorithm that operates on two numpy arrays of integers and runs in nopython mode, you can follow the structure below. This version of the Levenshtein distance algorithm includes a cost of 2 for character swaps, instead of the more traditional cost of 1. This means that substitution operations are penalized more heavily compared to insertions or deletions. First, ensure you have Numba and NumPy installed in your environment. You can install them using pip if you haven't already:
1 | pip install numba numpy |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | from numba import jit import numpy as np @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) + 1 len_arr2 = len(arr2) + 1 d = np.zeros((len_arr1, len_arr2), dtype=np.int32) for i in range(len_arr1): d[i, 0] = i for j in range(len_arr2): d[0, j] = j for i in range(1, len_arr1): for j in range(1, len_arr2): cost = 0 if arr1[i - 1] == arr2[j - 1] else 2 d[i, j] = min(d[i - 1, j] + 1, # deletion d[i, j - 1] + 1, # insertion d[i - 1, j - 1] + cost) # substitution return d[len_arr1 - 1, len_arr2 - 1] # Example usage: arr1 = np.array([1, 2, 3, 4]) arr2 = np.array([1, 3, 4, 2]) distance = levenshtein(arr1, arr2) print(f"Levenshtein distance: {distance}") |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | from numba import jit import numpy as np @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) + 1 len_arr2 = len(arr2) + 1 d = np.zeros((len_arr1, len_arr2), dtype=np.int32) for i in range(len_arr1): d[i, 0] = i for j in range(len_arr2): d[0, j] = j for i in range(1, len_arr1): for j in range(1, len_arr2): cost = 0 if arr1[i - 1] == arr2[j - 1] else 2 d[i, j] = min(d[i - 1, j] + 1, # deletion d[i, j - 1] + 1, # insertion d[i - 1, j - 1] + cost) # substitution return d[len_arr1 - 1, len_arr2 - 1] |
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | from numba import jit import numpy as np @jit(nopython=True) def levenshtein(arr1, arr2): len_arr1 = len(arr1) + 1 len_arr2 = len(arr2) + 1 d = np.zeros((len_arr1, len_arr2), dtype=np.int32) for i in range(len_arr1): d[i, 0] = i for j in range(len_arr2): d[0, j] = j for i in range(1, len_arr1): for j in range(1, len_arr2): cost = 0 if arr1[i - 1] == arr2[j - 1] else 2 d[i, j] = min(d[i - 1, j] + 1, # deletion d[i, j - 1] + 1, # insertion d[i - 1, j - 1] + cost) # substitution return d[len_arr1 - 1, len_arr2 - 1] answer = levenshtein(np.array([3, 5, 2, 4, 8, 7]), np.array([3, 4, 2, 4, 8, 7, 9])) expected = 3 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
All tests passed
Testing if the previous output contains the string All tests passed
: True
Testing if the previous output contains the string njit
: False
Testing if the previous output contains the string nopython
: True
Testing if the previous output contains the string import numba
: False
Testing if the previous output contains the string from numba
: True