`scipy.ndimage._measurements:sum_labels`

source: /scipy/ndimage/_measurements.py :715

Signature

def sum_labels ( input , labels = None , index = None )

Summary

Calculate the sum of the values of the array.

Parameters

input : array_like: Values of input inside the regions defined by labels are summed together.
labels : array_like of ints, optional: Assign labels to the values of the array. Has to have the same shape as input.
index : array_like, optional: A single label number or a sequence of label numbers of the objects to be measured.

Returns

sum : ndarray or scalar: An array of the sums of values of input inside the regions defined by labels with the same shape as index. If 'index' is None or scalar, a scalar is returned.

Notes

Array API Standard Support

sum_labels has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable SCIPY_ARRAY_API=1 and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

====================  ====================  ====================
Library               CPU                   GPU
====================  ====================  ====================
NumPy                 ✅                     n/a                 
CuPy                  n/a                   ✅                   
PyTorch               ✅                     ⛔                   
JAX                   ⚠️ no JIT             ⛔                   
Dask                  ⚠️ computes graph     n/a                 
====================  ====================  ====================

See dev-arrayapi for more information.

Examples

from scipy import ndimage
input =  [0,1,2,3]
labels = [1,1,2,2]

✓

ndimage.sum_labels(input, labels, index=[1,2])
ndimage.sum_labels(input, labels, index=1)
ndimage.sum_labels(input, labels)

✗

Aliases

scipy.ndimage.sum_labels