[Octave-bug-tracker] [bug #40294] Logical indexing into sparse matrix hangs

[David Bateman]

Follow-up Comment #1, bug #40294 (project octave):

This is known problem and is documented on the Projects page since 2006. See 

http://wiki.octave.org/Projects#Sparse_Matrices

where it says


Sparse logical indexing in idx_vector class so that something like
'a=sprandn(1e6,1e6,1e-6); a(a<1) = 0' won't cause a memory overflow.


At the moment the sparse logical indexing is converted in full matrix indexing
and in your case you're are probably swapping madly rather than getting a
memory overflow.

Its not that easy to implement and its always seemed that the amount of work
to implemen it was always more than it was worth since as you've found there
always seems to be a manner to work around it.

I'd suggest leaving this bug open, but giving it a low priority

D.

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