scipy.sparse.
identity#
- 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)>