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Topic: Large SparseArray in Mathematica 9 and the predictive interface
Replies: 3   Last Post: Jan 2, 2013 9:14 PM

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David Reiss

Posts: 603
Registered: 2/24/06
Re: Large SparseArray in Mathematica 9 and the predictive interface
Posted: Dec 31, 2012 7:45 PM
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of course you should report this as a bug to Wolfram Support....
--David

On Dec 30, 8:49 pm, jmm...@gmail.com wrote:
> Hi there,
>
> I was generating a banded sparse array with the following code
> in the new Mathematica 9.0:
>
> gmat[K_, l_, m_] :=
> Module[{bandU, bandL, bandD, res},
>
> bandU = Table[l, {K - 1}];
> bandL = Table[m, {K - 1}];
> bandD = Table[-l - m, {K}];
> bandD[[1]] = -l;
> bandD[[K]] = -m;
>
> res = DiagonalMatrix[SparseArray[bandU], 1]
> + DiagonalMatrix[SparseArray[bandD]]
> + DiagonalMatrix[SparseArray[bandL], -1];
>
> Return[res];
> ];
>
> then I used the function with the following parameters (without semicolon:
>
> gmat[100, 0.8, 1]
>
> ...and everything was ok! a 100x100 sparse matrix was created and the
> "predictive interface bar" appeared.
>
> Nevertheless, when I typed (without semicolon):
>
> gmat[10000, 0.8, 1]
>
> ...everything went not so good, a 10000x10000 sparse matrix was created
> (what was ok), but the kernel went nuts with the memory use, some gigabytes
> for a small sparsearray (You can try with greater parameters, but starting
> with K=5000 things go weird)
>
> I think the problem has to do with the "predictive interface" that tries to
> generate the normal form of the matrix, so it uses a lot of memory (and even
> produces a kernel crash).
>
> Has anyone had the same problem with SparseArray? or have any
> explanation to what actually happens? or it is just me?
>
> Many thanks in advance for any help or advice with this issue.
>
> Regards,
>
> Jose M. Martinez
> Ph.D. Student
> Department of Electronic Engineering
> Universidad Tecnica Federico Santa Maria
> Valparaiso, Chile






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