`numpy:trace`

source: /dev/numpy/build-install/usr/lib/python3.14/site-packages/numpy/_core/fromnumeric.py :1806

Signature

   def     trace (    a    ,    offset    =  0   ,    axis1    =  0   ,    axis2    =  1   ,    dtype    =  None   ,    out    =  None     )

Summary

Return the sum along diagonals of the array.

Extended Summary

If a is 2-D, the sum along its diagonal with the given offset is returned, i.e., the sum of elements a[i,i+offset] for all i.

If a has more than two dimensions, then the axes specified by axis1 and axis2 are used to determine the 2-D sub-arrays whose traces are returned. The shape of the resulting array is the same as that of a with axis1 and axis2 removed.

Parameters

a : array_like: Input array, from which the diagonals are taken.
offset : int, optional: Offset of the diagonal from the main diagonal. Can be both positive and negative. Defaults to 0.
axis1, axis2 : int, optional: Axes to be used as the first and second axis of the 2-D sub-arrays from which the diagonals should be taken. Defaults are the first two axes of a.
dtype : dtype, optional: Determines the data-type of the returned array and of the accumulator where the elements are summed. If dtype has the value None and a is of integer type of precision less than the default integer precision, then the default integer precision is used. Otherwise, the precision is the same as that of a.
out : ndarray, optional: Array into which the output is placed. Its type is preserved and it must be of the right shape to hold the output.

Returns

sum_along_diagonals : ndarray: If a is 2-D, the sum along the diagonal is returned. If a has larger dimensions, then an array of sums along diagonals is returned.

Examples

import numpy as np

✓

np.trace(np.eye(3))

✗

a = np.arange(8).reshape((2,2,2))
np.trace(a)

✓

a = np.arange(24).reshape((2,2,2,3))
np.trace(a).shape

`numpy:trace`

Signature

Summary

Extended Summary

Parameters

Returns

Examples

See also

Aliases

Referenced by

This package