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How to change memory layout of a 2D NumPy array to F order?


Write a NumPy program that creates a 2D array of shape (3, 3), change its memory layout to 'F' order using asfortranarray(), and print the array and its strides.

Sample Solution:

Python Code:

import numpy as np

# Create a 2D array of shape (3, 3)
array_2d = np.array([[1, 2, 3],
                     [4, 5, 6],
                     [7, 8, 9]])

# Change the memory layout to 'F' order
array_f_order = np.asfortranarray(array_2d)

# Print the array in 'F' order
print("Array in 'F' order:\n", array_f_order)

# Print the strides of the array in 'F' order
print("Strides of the array in 'F' order:", array_f_order.strides)

Output:

Array in 'F' order:
 [[1 2 3]
 [4 5 6]
 [7 8 9]]
Strides of the array in 'F' order: (4, 12)

Explanation:

  • Import NumPy library: We start by importing the NumPy library to handle array operations.
  • Create a 2D array: We create a 2D array array_2d of shape (3, 3) using np.array().
  • Change memory layout to 'F' order: We use np.asfortranarray() to ensure the array is stored in column-major ('F') order, resulting in array_f_order.
  • Print the array: We print array_f_order to display the array in 'F' order.
  • Print the strides: We print the strides of array_f_order using the strides attribute to show the number of bytes to step in each dimension when traversing the array.

Python-Numpy Code Editor: