Vectorize this update loop. Call the function `update`: import numpy as np def update(high, highest_number, delta): for i in range(len(high)): if i != highest_number: high[i] = min(high[i], high[highest_number] + delta[highest_number] - delta[i]) return high
Vectorize this update loop. Call the function `update`: import numpy as np def update(high, highest_number, delta): for i in range(len(high)): if i != highest_number: high[i] = min(high[i], high[highest_number] + delta[highest_number] - delta[i]) return high
To vectorize the given loop, we can utilize NumPy's array operations to eliminate the explicit loop, making the code more efficient and concise. The approach involves creating a boolean mask to identify the elements to update and then applying the update in a vectorized manner. ### Approach 1. **Boolean Mask**: Create a boolean mask where all elements are `True` except for the index specified by `highest_number`. 2. **Compute New Values**: Calculate the potential new values for all elements using vectorized operations. The new value for each element is derived from the highest element and the corresponding deltas. 3. **Element-wise Minimum**: Use the boolean mask to apply the minimum operation only to the relevant elements, updating them to the lesser of their current value or the computed new value. ### Solution Code
1 2 3 4 5 6 7 | import numpy as np def update(high, highest_number, delta): mask = np.arange(len(high)) != highest_number new_values = high[highest_number] + (delta[highest_number] - delta) high[mask] = np.minimum(high[mask], new_values[mask]) return high |
I extracted the following code from that output:
1 2 3 4 5 6 7 | import numpy as np def update(high, highest_number, delta): mask = np.arange(len(high)) != highest_number new_values = high[highest_number] + (delta[highest_number] - delta) high[mask] = np.minimum(high[mask], new_values[mask]) return high |
Below is a student's answer to a question about how to vectorize this loop: def update(high, highest_number, delta): for i in range(len(high)): if i != highest_number: high[i] = min(high[i], high[highest_number] + delta[highest_number] - delta[i]) return high Here is their code: import numpy as np def update(high, highest_number, delta): mask = np.arange(len(high)) != highest_number new_values = high[highest_number] + (delta[highest_number] - delta) high[mask] = np.minimum(high[mask], new_values[mask]) return high Did the student try to vectorize the loop? Don't tell me if they are correct or not. (I have tests for that separately which will catch any bugs.) Just tell me if they tried to vectorize the loop. End your answer with either the string "The student passes" if they tried to do a vectorized loop, or "The student fails" if they just wrote a for loop again.
The student passes
Testing if the previous output contains the string student passes
: True
Running the following program:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | import numpy as np def update(high, highest_number, delta): mask = np.arange(len(high)) != highest_number new_values = high[highest_number] + (delta[highest_number] - delta) high[mask] = np.minimum(high[mask], new_values[mask]) return high import numpy as np answer = list(update(np.array([2, 5, 9, 1, 2, 0, 3, 8]), 4, np.array([1, 2, 1, 4, 3, 2, 1, 2]))) expected = [2, 3, 4, 1, 2, 0, 3, 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