[Scipy-tickets] [SciPy] #1598: Bad behavior of sparse matrices in a binary ufunc

SciPy Trac scipy-tickets@scipy....
Fri Feb 17 05:26:48 CST 2012

#1598: Bad behavior of sparse matrices in a binary ufunc
 Reporter:  pv            |       Owner:  wnbell     
     Type:  defect        |      Status:  new        
 Priority:  normal        |   Milestone:  Unscheduled
Component:  scipy.sparse  |     Version:  0.10.0     
 Keywords:                |  
 This behavior should be improved:
 import numpy as np
 import scipy.sparse as sp
 A = sp.csc_matrix(np.identity(5))
 B = np.asmatrix(np.ones((5,5)))
 print np.multiply(A,A)
 # <5x5 sparse matrix of type '<class 'numpy.float64'>'
 #       with 5 stored elements in Compressed Sparse Column format>
 print np.multiply(B,A)
 # NotImplemented
 print np.multiply(A,B).dtype
 # object

 I don't actually follow what happens in the last one --- according to pdb,
 the execution never reaches `csc_matrix.multiply`. Instead, one gets calls
 to `csc_matrix.__mul__`.

 Also, these routines should never return NotImplemented.

Ticket URL: <http://projects.scipy.org/scipy/ticket/1598>
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