Broken: scipy.io.mmread with scipy.sparse.lil_matrix (Trac #883)

[scipy-gitbot]

Original ticket http://projects.scipy.org/scipy/ticket/883 on 2009-03-08 by trac user kyleabeauchamp, assigned to @wnbell.

version scipy 0.7.0 (can't select this version in the drop down box)
IMHO, this should be a relatively simple fix; I believe that scipy.io.mmread just needs a bit more error checking for matrix sizes.

Problem: when you initialize an empty lil_matrix, write it to disk using mmwrite, and read it back in from disk, scipy crashes with

*** glibc detected *** /usr/bin/python: double free or corruption (top): 0x09e113a8 ***

Sample code causing the problem:

In [1]: import scipy.io

In [2]: import scipy.sparse

In [3]: A=scipy.sparse.lil_matrix((100,100))

In [4]: scipy.io.mmwrite("Broken.mtx",A)

In [5]: scipy.io.mmread("Broken.mtx")
*** glibc detected *** /usr/bin/python: double free or corruption (top): 0x09e113a8 ***

Here is the file Broken.mtx:

kyle@kyle-laptop:/opt$ cat Broken.mtx 
%%MatrixMarket matrix coordinate real general
%
100 100 0

[scipy-gitbot]

Milestone changed to 0.7.1 by @wnbell on 2009-03-08

[scipy-gitbot]

@wnbell wrote on 2009-03-08

Thanks for the report Kyle. This has been fixed in 9cc779d and should appear in SciPy 0.7.1.

Also, you can now report bugs against version 0.7.0.