numpy.ix_()

numpy.ix_(*args) [source]

Construct an open mesh from multiple sequences.

This function takes N 1-D sequences and returns N outputs with N dimensions each, such that the shape is 1 in all but one dimension and the dimension with the non-unit shape value cycles through all N dimensions.

Using ix_ one can quickly construct index arrays that will index the cross product. a[np.ix_([1,3],[2,5])] returns the array [[a[1,2] a[1,5]], [a[3,2] a[3,5]]].

Parameters:

Parameters:	args : 1-D sequences
Returns:	out : tuple of ndarrays N arrays with N dimensions each, with N the number of input sequences. Together these arrays form an open mesh.

args : 1-D sequences

Returns:

out : tuple of ndarrays

N arrays with N dimensions each, with N the number of input sequences. Together these arrays form an open mesh.

Examples

>>> a = np.arange(10).reshape(2, 5)
>>> a
array([[0, 1, 2, 3, 4],
       [5, 6, 7, 8, 9]])
>>> ixgrid = np.ix_([0,1], [2,4])
>>> ixgrid
(array([[0],
       [1]]), array([[2, 4]]))
>>> ixgrid[0].shape, ixgrid[1].shape
((2, 1), (1, 2))
>>> a[ixgrid]
array([[2, 4],
       [7, 9]])

Links:

https://docs.scipy.org/doc/numpy-1.11.0/reference/generated/numpy.ix_.html

doc_NumPy

2025-01-10 15:47:30

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