[SciPy-dev] Kronecker sum of sparse matrices
Nils Wagner
nwagner at iam.uni-stuttgart.de
Sat Feb 9 13:21:01 EST 2008
Hi all,
I have written a function for the Kronecker sum
of sparse matrices. It is meant for
http://projects.scipy.org/scipy/scipy/ticket/313
def spkronsum(a,b):
"""kronecker sum of a and b
Kronecker sum of two sparse matrices is a sum
of two Kronecker products kron(I_m,a)+kron(b,I_n)
Inputs:
a -- An n x n sparse matrix.
b -- An m x m sparse matrix
"""
m,n = b.get_shape()
p,q = a.get_shape()
if p != q:
raise ValueError, 'expected square matrix'
if m != n:
raise ValueError, 'expected square matrix'
return spkron(speye(m,n),a)+spkron(b,speye(p,q))
Cheers,
Nils
>>> B = coo_matrix([[1.+1j,2],[3,4-1j]])
>>> print B
(0, 0) (1.0+1.0j)
(0, 1) (2.0+0.0j)
(1, 0) (3.0+0.0j)
(1, 1) (4.0+-1.0j)
The last entry in B contains a typo "+-"
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