bugGNU Octave - Bugs: bug #40712, Running into index errors with...

 
 

bug #40712: Running into index errors with large, 64k square sparse matrices

Submitted by:  Paul Jakma <paul>
Submitted on:  Tue 26 Nov 2013 04:56:38 PM UTC  
 
Category: Octave FunctionSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Performance
Status: ConfirmedAssigned to: None
Originator Name: Open/Closed: Open
Release: devOperating System: GNU/Linux

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Tue 26 Nov 2013 04:56:38 PM UTC, original submission:

I have a 64k × 64 matrix, sparse matrix:

spstats(D)
ans =
Compressed Column Sparse (rows = 1, cols = 64000, nnz = 15892 [25%])
...

I wanted to calculate D^-0.5, however it gives this error:

D = D**-0.5

error: memory exhausted or requested size too large for range of Octave's index type -- trying to return to prompt

It was suggested to me to on #octave use:

D(D>0) .^= -0.5

However, this gives the same error. In the end, the following workaround was found, which does work:

Ds = diag(D);
Ds(Ds > 0) .^= -0.5;
Ds = diag(Ds);

It would be good though if the first 2 ways above worked too.

While my matrices at the moment are 64k in size, they are likely to grow. They are actually large graphs, in a 32bit node space. The 64k size will grow and grow over time. Octave has been extremely useful in helping to analyse these graphs. It'd be very useful to me if Octave's index type could support operations on them.

Paul Jakma <paul>

 

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  • -unavailable- added by mtmiller (Updated the item)
  • -unavailable- added by paul (Submitted the item)
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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 19 Jan 2014 07:14:44 PM UTCmtmillerCategoryNone=>Octave Function
      StatusNone=>Confirmed
      Release3.6.3=>dev

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