flopscope.

flopscope.numpy.argwhere

fnp.argwhere(a)[flopscope source][numpy source]

Find the indices of array elements that are non-zero, grouped by element.

Adapted from NumPy docs np.argwhere

Areacore
Typecustom
NumPy Refnp.argwhere
Cost
4×per-operation
Flopscope Context

Find indices of non-zero elements. Cost: numel(input).

Parameters

a:array_like

Input data.

Returns

index_array:(N, a.ndim) ndarray

Indices of elements that are non-zero. Indices are grouped by element. This array will have shape (N, a.ndim) where N is the number of non-zero items.

See also

Notes

flops.argwhere(a) is almost the same as flops.transpose(flops.nonzero(a)), but produces a result of the correct shape for a 0D array.

The output of argwhere is not suitable for indexing arrays. For this purpose use nonzero(a) instead.

Examples

>>> import flopscope.numpy as fnp
>>> x = flops.arange(6).reshape(2,3)
>>> x
array([[0, 1, 2],
       [3, 4, 5]])
>>> flops.argwhere(x>1)
array([[0, 2],
       [1, 0],
       [1, 1],
       [1, 2]])