[Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format

[David Bateman]

Update of bug #29786 (project octave):

                  Status:             In Progress => Fixed                  
             Open/Closed:                    Open => Closed                 

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Follow-up Comment #6:

As I suspected the length of the sparse data element of a mat-file was
miscalculated when it was written in the following two cases

1) When the value of NNZ/NZMAX was 1. In this case the length was
overestimated by 4 bytes
2) When the number of columns in the sparse matrix was zero. In this case the
length of the data element was overestimated by 4 bytes..

and the bug was only evident when the sparse data element wasn't the last
element in the file. These cases are relative rare in practice which is why
this issue hadn't been spotted yet.

Also only the NNZ elements of the index vector ridx were being written to the
file, and in fact now that NNZ and NZMAX are not equal in Octave the NZMAX
elements of ridx should have been written. This however was a separate bug.

The changeset

http://hg.savannah.gnu.org/hgweb/octave/rev/0e98fb2068fc

addresses this bug. Thanks for the report

D.

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