Problem with spotrs_ method.

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Problem with spotrs_ method.

Postby ythnmj » Wed Oct 12, 2011 4:47 am

Before i ask this question i just want to ask, where can i find a decent manual with few working examples for CLAPACK? Its been 2 days i am using it and i couldnt find any online reference to it.

I am trying to solves a system of linear equations A*X = B with a symmetric positive definite matrix A using the Cholesky factorization.

My Dimension of A is 3500 by 3500 and B is 4 by 3500.

I am trying to use spotrs_ method to do so.

Before i am calling sports_, i am calling spotrf_(&uplo,&n,A,&lda,&info); where i have taylormade r11 irons='L'; n=3500;lda=3500.

The after i get A, i call spotrs_ method, spotrs_(&uplo,&n,&nrhs,A,&lda,B,&ldb,&info) where uplo='L', n=3500, nrhs=3500, lda=3500, lbd=3500.

With following parameters, i get following error:- Unhandled exception at 0x01073e3d in Interpolate.exe: 0xC0000005: Access violation reading location 0x0ad67000.

My Matrix A and B are real and converted in 1D i.e. A is 3500*3500 long and B is 4*3500 long.

help me
Last edited by ythnmj on Tue Nov 08, 2011 3:11 am, edited 1 time in total.
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Joined: Wed Oct 12, 2011 3:54 am

Re: Problem with spotrs_ method.

Postby error5772 » Sat Oct 22, 2011 3:49 am


Have you tried nrhs=4 ?

Posts: 19
Joined: Thu Sep 01, 2011 5:02 am

Re: Problem with spotrs_ method.

Postby Julien Langou » Tue Nov 08, 2011 11:35 am

B should be 3500*4. So I am not sure what you mean by 4*3500. Also I agree with Michael: nrhs needs to be 4 for sure. Julien.
Julien Langou
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Location: Denver, CO, USA

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