discretize.utils.get_subarray#

discretize.utils.get_subarray(A, ind)[source]#

Extract a subarray.

For a numpy.ndarray, the function get_subarray extracts a subset of the array. The portion of the original array being extracted is defined by providing the indices along each axis.

Parameters:

Anumpy.ndarray: The original numpy array. Must be 1, 2 or 3 dimensions.
ind(dim) list of numpy.ndarray: A list of numpy arrays containing the indices being extracted along each dimension. The length of the list must equal the dimensions of the input array.

Returns:

numpy.ndarray: The subarray extracted from the original array

Examples

Here we construct a random 3x3 numpy array and use get_subarray to extract the first column.

>>> from discretize.utils import get_subarray
>>> import numpy as np
>>> rng = np.random.default_rng(421)
>>> A = rng.random((3, 3))
>>> A
array([[1.07969034e-04, 9.78613931e-01, 6.62123429e-01],
       [8.80722877e-01, 7.61035691e-01, 7.42546796e-01],
       [9.09488911e-01, 7.80626334e-01, 8.67663825e-01]])

Define the indexing along the columns and rows and create the indexing list

>>> ind_x = np.array([0, 1, 2])
>>> ind_y = np.array([0, 2])
>>> ind = [ind_x, ind_y]

Extract the first, and third column of A

>>> get_subarray(A, ind)
array([[1.07969034e-04, 6.62123429e-01],
       [8.80722877e-01, 7.42546796e-01],
       [9.09488911e-01, 8.67663825e-01]])