Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
Certainly! The "strided trick" in NumPy can be utilized to create overlapping slices of an array efficiently. Below is a Python function named `strides()` that implements this idea. The function takes a NumPy array as input and returns a list of overlapping slices of the specified size.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | import numpy as np def strides(T, window_size=50, step=10): # Calculate the number of strides based on the length of T num_strides = (len(T) - window_size) // step + 1 # Create an array of indices for the starting points of the slices indices = np.arange(num_strides) * step # Use advanced indexing to create strided views return [T[i:i + window_size] for i in indices] # Example usage T = np.arange(100) # Example array result = strides(T) for r in result: print(r) |
1 2 3 4 | [ 0 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 39 40 41 42 43 44 45 46 47 48 49] [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 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59] [20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69] ... |
I extracted the following code from that output:
1 2 3 4 5 6 7 8 9 10 11 | import numpy as np def strides(T, window_size=50, step=10): # Calculate the number of strides based on the length of T num_strides = (len(T) - window_size) // step + 1 # Create an array of indices for the starting points of the slices indices = np.arange(num_strides) * step # Use advanced indexing to create strided views return [T[i:i + window_size] for i in indices] |
Testing if the previous output contains the string as_strided
: False
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 | import numpy as np def strides(T, window_size=50, step=10): # Calculate the number of strides based on the length of T num_strides = (len(T) - window_size) // step + 1 # Create an array of indices for the starting points of the slices indices = np.arange(num_strides) * step # Use advanced indexing to create strided views return [T[i:i + window_size] for i in indices] answer = strides(np.arange(100)).shape expected = (6, 50) assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' answer = strides(np.arange(100)).sum() expected = 14850 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Traceback (most recent call last):
File "/usr/src/app/main.py", line 18, in <module>
answer = strides(np.arange(100)).shape
AttributeError: 'list' object has no attribute 'shape'
Testing if the previous output contains the string All tests passed
: False
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
To implement the `strides()` function that uses the strided trick with a given numpy array of tokens \( T \), we can utilize numpy's array slicing capabilities. The goal is to create overlapping slices of the array that start from each index \( i \) and capture the next 50 elements, moving by 10 elements for each new slice. Here is how you can implement this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | import numpy as np def strides(T): # Calculate the number of slices we can make num_slices = (len(T) - 50) // 10 + 1 # Generate the slices using list comprehension result = [T[i:i+50] for i in range(0, num_slices * 10, 10)] return result # Example usage tokens = np.arange(100) # Creating an example numpy array of tokens result = strides(tokens) for i, r in enumerate(result): print(f"Slice {i}: {r}") |
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 | import numpy as np def strides(T): # Calculate the number of slices we can make num_slices = (len(T) - 50) // 10 + 1 # Generate the slices using list comprehension result = [T[i:i+50] for i in range(0, num_slices * 10, 10)] return result # Example usage tokens = np.arange(100) # Creating an example numpy array of tokens result = strides(tokens) for i, r in enumerate(result): print(f"Slice {i}: {r}") |
Testing if the previous output contains the string as_strided
: False
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 | import numpy as np def strides(T): # Calculate the number of slices we can make num_slices = (len(T) - 50) // 10 + 1 # Generate the slices using list comprehension result = [T[i:i+50] for i in range(0, num_slices * 10, 10)] return result # Example usage tokens = np.arange(100) # Creating an example numpy array of tokens result = strides(tokens) for i, r in enumerate(result): print(f"Slice {i}: {r}") answer = strides(np.arange(100)).shape expected = (6, 50) assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' answer = strides(np.arange(100)).sum() expected = 14850 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
Slice 0: [ 0 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 39 40 41 42 43 44 45 46 47
48 49]
Slice 1: [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 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57
58 59]
Slice 2: [20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67
68 69]
Slice 3: [30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
78 79]
Slice 4: [40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87
88 89]
Slice 5: [50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73
74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97
98 99]
Traceback (most recent call last):
File "/usr/src/app/main.py", line 24, in <module>
answer = strides(np.arange(100)).shape
AttributeError: 'list' object has no attribute 'shape'
Testing if the previous output contains the string All tests passed
: False
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
To implement the `strides()` function that utilizes the strided trick in NumPy, you can leverage the `numpy.lib.stride_tricks.as_strided` function. This allows you to create views of the original array with overlapping slices efficiently. Below is a sample implementation of the `strides()` function that takes a NumPy array of tokens and returns the required overlapping slices. Here's how you can implement this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | import numpy as np def strides(T): # Ensure T is a numpy array T = np.asarray(T) # Define the shape and strides for the new view shape = (len(T) - 50 + 1, 50) # Number of windows and the window size (50) strides = (T.strides[0], T.strides[0]) # Stride in the first dimension and window size # Use as_strided to create the overlapping slices strided_array = np.lib.stride_tricks.as_strided(T, shape=shape, strides=strides) return strided_array # Example usage: if __name__ == "__main__": # Create a sample array of tokens tokens = np.arange(100) # Example array with 100 tokens result = strides(tokens) print(result) |
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 | import numpy as np def strides(T): # Ensure T is a numpy array T = np.asarray(T) # Define the shape and strides for the new view shape = (len(T) - 50 + 1, 50) # Number of windows and the window size (50) strides = (T.strides[0], T.strides[0]) # Stride in the first dimension and window size # Use as_strided to create the overlapping slices strided_array = np.lib.stride_tricks.as_strided(T, shape=shape, strides=strides) return strided_array # Example usage: if __name__ == "__main__": # Create a sample array of tokens tokens = np.arange(100) # Example array with 100 tokens result = strides(tokens) print(result) |
Testing if the previous output contains the string as_strided
: True
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 | import numpy as np def strides(T): # Ensure T is a numpy array T = np.asarray(T) # Define the shape and strides for the new view shape = (len(T) - 50 + 1, 50) # Number of windows and the window size (50) strides = (T.strides[0], T.strides[0]) # Stride in the first dimension and window size # Use as_strided to create the overlapping slices strided_array = np.lib.stride_tricks.as_strided(T, shape=shape, strides=strides) return strided_array # Example usage: if __name__ == "__main__": # Create a sample array of tokens tokens = np.arange(100) # Example array with 100 tokens result = strides(tokens) print(result) answer = strides(np.arange(100)).shape expected = (6, 50) assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' answer = strides(np.arange(100)).sum() expected = 14850 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
[[ 0 1 2 ... 47 48 49]
[ 1 2 3 ... 48 49 50]
[ 2 3 4 ... 49 50 51]
...
[48 49 50 ... 95 96 97]
[49 50 51 ... 96 97 98]
[50 51 52 ... 97 98 99]]
Traceback (most recent call last):
File "/usr/src/app/main.py", line 30, in <module>
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'
AssertionError: Wrong answer; got (51, 50) instead of (6, 50)
Testing if the previous output contains the string All tests passed
: False
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
You can achieve this using NumPy's striding capabilities, which allow you to create views of the original array without copying the data. Below is a Python function `strides()` that takes a NumPy array `T` and returns a list of subarrays using the strided trick you described. Here’s how you can implement the `strides()` function:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | import numpy as np def strides(T): # Ensure T is a numpy array T = np.asarray(T) # Create an array of shape (n, 50) where n is the number of strides we can take n = len(T) - 50 + 1 # The number of windows we can extract if n <= 0: return [] # If there are not enough elements for a single window # Use striding to create the required windows return np.lib.stride_tricks.as_strided(T, shape=(n, 50), strides=(T.strides[0], T.strides[0])) # Example usage: T = np.arange(100) # Example input array result = strides(T) print(result) |
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 | import numpy as np def strides(T): # Ensure T is a numpy array T = np.asarray(T) # Create an array of shape (n, 50) where n is the number of strides we can take n = len(T) - 50 + 1 # The number of windows we can extract if n <= 0: return [] # If there are not enough elements for a single window # Use striding to create the required windows return np.lib.stride_tricks.as_strided(T, shape=(n, 50), strides=(T.strides[0], T.strides[0])) # Example usage: T = np.arange(100) # Example input array result = strides(T) print(result) |
Testing if the previous output contains the string as_strided
: True
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 | import numpy as np def strides(T): # Ensure T is a numpy array T = np.asarray(T) # Create an array of shape (n, 50) where n is the number of strides we can take n = len(T) - 50 + 1 # The number of windows we can extract if n <= 0: return [] # If there are not enough elements for a single window # Use striding to create the required windows return np.lib.stride_tricks.as_strided(T, shape=(n, 50), strides=(T.strides[0], T.strides[0])) # Example usage: T = np.arange(100) # Example input array result = strides(T) print(result) answer = strides(np.arange(100)).shape expected = (6, 50) assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' answer = strides(np.arange(100)).sum() expected = 14850 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
[[ 0 1 2 ... 47 48 49]
[ 1 2 3 ... 48 49 50]
[ 2 3 4 ... 49 50 51]
...
[48 49 50 ... 95 96 97]
[49 50 51 ... 96 97 98]
[50 51 52 ... 97 98 99]]
Traceback (most recent call last):
File "/usr/src/app/main.py", line 27, in <module>
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'
AssertionError: Wrong answer; got (51, 50) instead of (6, 50)
Testing if the previous output contains the string All tests passed
: False
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
Write a function strides() that given an array of tokens T as numpy array, using strided trick, returns [T[0:50], T[10:60], T[20: 70] ... ]
To implement the `strides` function using the strided trick in NumPy, you can utilize the `np.lib.stride_tricks` module, which allows you to create views of arrays with different strides. Here's how you can do it:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | import numpy as np def strides(T): # Check if the input array has at least 60 elements if len(T) < 60: raise ValueError("Input array must have at least 60 elements.") # Define the shape of the output array shape = (T.size - 50 + 1, 50) # Number of windows and window size # Define the strides of the original array strides = (T.strides[0], T.strides[0]) # Strides for the new array # Create the strided array strided_array = np.lib.stride_tricks.as_strided(T, shape=shape, strides=strides) return strided_array # Example usage: T = np.arange(100) # Example array with 100 elements result = strides(T) print(result) |
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 | import numpy as np def strides(T): # Check if the input array has at least 60 elements if len(T) < 60: raise ValueError("Input array must have at least 60 elements.") # Define the shape of the output array shape = (T.size - 50 + 1, 50) # Number of windows and window size # Define the strides of the original array strides = (T.strides[0], T.strides[0]) # Strides for the new array # Create the strided array strided_array = np.lib.stride_tricks.as_strided(T, shape=shape, strides=strides) return strided_array # Example usage: T = np.arange(100) # Example array with 100 elements result = strides(T) print(result) |
Testing if the previous output contains the string as_strided
: True
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 | import numpy as np def strides(T): # Check if the input array has at least 60 elements if len(T) < 60: raise ValueError("Input array must have at least 60 elements.") # Define the shape of the output array shape = (T.size - 50 + 1, 50) # Number of windows and window size # Define the strides of the original array strides = (T.strides[0], T.strides[0]) # Strides for the new array # Create the strided array strided_array = np.lib.stride_tricks.as_strided(T, shape=shape, strides=strides) return strided_array # Example usage: T = np.arange(100) # Example array with 100 elements result = strides(T) print(result) answer = strides(np.arange(100)).shape expected = (6, 50) assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' answer = strides(np.arange(100)).sum() expected = 14850 assert answer == expected, f'Wrong answer; got {answer} instead of {expected}' print('All tests passed') |
[[ 0 1 2 ... 47 48 49]
[ 1 2 3 ... 48 49 50]
[ 2 3 4 ... 49 50 51]
...
[48 49 50 ... 95 96 97]
[49 50 51 ... 96 97 98]
[50 51 52 ... 97 98 99]]
Traceback (most recent call last):
File "/usr/src/app/main.py", line 30, in <module>
assert answer == expected, f'Wrong answer; got {answer} instead of {expected}'
AssertionError: Wrong answer; got (51, 50) instead of (6, 50)
Testing if the previous output contains the string All tests passed
: False