identity — SciPy v1.15.3 Manual (original) (raw)

scipy.sparse.

scipy.sparse.identity(n, dtype='d', format=None)[source]#

Identity matrix in sparse format

Returns an identity matrix with shape (n,n) using a given sparse format and dtype. This differs from eye_array in that it has a square shape with ones only on the main diagonal. It is thus the multiplicative identity. eye_array allows rectangular shapes and the diagonal can be offset from the main one.

Warning

This function returns a sparse matrix – not a sparse array. You are encouraged to use eye_array to take advantage of the sparse array functionality.

Parameters:

nint

Shape of the identity matrix.

dtypedtype, optional

Data type of the matrix

formatstr, optional

Sparse format of the result, e.g., format=”csr”, etc.

Examples

import scipy as sp sp.sparse.identity(3).toarray() array([[ 1., 0., 0.], [ 0., 1., 0.], [ 0., 0., 1.]]) sp.sparse.identity(3, dtype='int8', format='dia') <DIAgonal sparse matrix of dtype 'int8' with 3 stored elements (1 diagonals) and shape (3, 3)> sp.sparse.eye_array(3, dtype='int8', format='dia') <DIAgonal sparse array of dtype 'int8' with 3 stored elements (1 diagonals) and shape (3, 3)>