Re: [Pkg-octave-devel] Bug#394982: octave2.9: Crashes on "x(:,

[John W. Eaton]

On 25-Oct-2006, John W. Eaton wrote:

| so it seems OK, but what is happening here:
| 
|   octave:1> x = sparse (2,0)
|   x = Compressed Column Sparse (rows = 2, cols = 0, nnz = 0)
| 
|   octave:2> x(:,2,3) = speye (2)
|   error: A(I, J) = X: can only have 1 or 2 indexes for sparse matrices
|   error: assignment failed, or no method for `sparse matrix = sparse matrix'
|   error: evaluating assignment expression near line 2, column 10
|   octave:2> x
|   x = Compressed Column Sparse (rows = 2, cols = 0, nnz = 0)
| 
|   octave:3> x(:,1:2) = speye (2)
|   error: A(I, J) = X: can only have 1 or 2 indexes for sparse matrices
|   error: assignment failed, or no method for `sparse matrix = sparse matrix'
|   error: evaluating assignment expression near line 3, column 10
| 
| The command on line 2 was a mistake, but it seems to have a persistent
| effect.  Even though x still seems to be a 2x0 sparse matrix,
| subsequent assignments fail after the first failure.  Clearing x
| allows it to work again, but how is it that the error is causing the
| later failures?

Never mind, I found the problem.  The indices for the LHS were not
being cleared.  I fixed it. with the following change.  I checked in
your previous change and this one.

Thanks,

jwe

liboctave/ChangeLog:

2006-10-25  John W. Eaton  <address@hidden>

        * Sparse.cc (assign): Clear lhs index after error.


Index: liboctave/Sparse.cc
===================================================================
RCS file: /cvs/octave/liboctave/Sparse.cc,v
retrieving revision 1.19
diff -u -u -r1.19 Sparse.cc
--- liboctave/Sparse.cc 25 Oct 2006 01:40:26 -0000      1.19
+++ liboctave/Sparse.cc 25 Oct 2006 23:44:11 -0000
@@ -2387,6 +2387,8 @@
     {
       (*current_liboctave_error_handler)
         ("A(I, J) = X: can only have 1 or 2 indexes for sparse matrices");
+
+      lhs.clear_index ();
       return 0;
     }