[SciPy-user] [Sparse matrix library] csr_matrix and column sum

David Cournapeau david@ar.media.kyoto-u.ac...
Sun Apr 27 23:56:22 CDT 2008

Dinesh B Vadhia wrote:
> I'm using the svn.  There is no Traceback error but the results are 
> incorrect based on previous results.  Here is ouput from print 
> statements that might help:
> > import numpy
> > import scipy
> > from scipy import sparse
> > colSum = scipy.asmatrix(scipy.zeros((1,J), dtype=numpy.float))
> > colSum = A.sum(0)            # A is a csr_matrix

I don't know if this is intended, but the first line has no effect 
(scipy.asmatrix: the call is wasteful because colSum will be assigned to 
A.sum(0) just after). We need the A matrix.


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