[Octave-bug-tracker] [bug #45963] sparse matrices with negative size

[Kai Torben Ohlhus]

Follow-up Comment #2, bug #45963 (project octave):

The erroneous behavior of comment #1 has it roots very deep inside 
liboctave/array/Spase.h . There is


SparseRep (octave_idx_type nr, octave_idx_type nc, octave_idx_type nz = 0)
  : d (nz > 0 ? new T [nz] : 0),
    r (nz > 0 ? new octave_idx_type [nz] : 0),
    c (new octave_idx_type [nc+1]), nzmx (nz), nrows (nr),
    ncols (nc), count (1)
{
  for (octave_idx_type i = 0; i < nc + 1; i++)
    c[i] = 0;
}


When you call


>> s = sparse(1e20,1)


nr = 1e20 and nc = 1 get directly forwarded from the interpreter only with a
check for nonnegativity!!! If you swapped the parameters, nc = 1e20 causes the
creation of a too large array and results in a bad_alloc exception.

To my opinion this is a problem that should be addressed in the dim_vector
class. It should be impossible to exceed the min and max index.

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