Re: Bug with numel() and sparsity?

[Kai Torben Ohlhus]

On Mon, Mar 3, 2014 at 7:29 PM, fork <address@hidden> wrote:

I am currently playing around with sedumi (thanks Michael!), and I ran into
this error with very big sparse matrices:

debug> OCTAVE_VERSION
ans = 3.8.1-rc3
debug> size(x)
ans =

   400002   200020

debug> nnz(x)
ans =  600000
debug> numel(x)
error: out of memory or dimension too large for Octave's index type

Is this a bug in numel()?  Or should numel() never be used with large sparse
matrices (and thus a bug in sedumi)?

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Hi,

Your problem might be related to the fact, that the standard octave uses 32 bit indices rather than 64 bit [1]. There have been previous discussion about this issue [2]. The major problem is, that Octave's dependencies have to use 64-bit pointers as well to work correctly.

HTH, Kai

[1] https://www.gnu.org/software/octave/doc/interpreter/Compiling-Octave-with-64_002dbit-Indexing.html

[2] http://octave.1599824.n4.nabble.com/Re-Pkg-octave-devel-Bug-706376-octave-sparse-matrix-n-2-16-td4652439.html#none