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LAPACK_?syconv interface problem

PostPosted: Thu Jul 09, 2015 12:41 am
by Victor_K
FORTRAN interface
SUBROUTINE DSYCONV( UPLO, WAY, N, A, LDA, IPIV, WORK, INFO )
has argument WORK which contains some useful information on exit:

DSYCONV convert A given by TRF into L and D and vice-versa.
Get Non-diag elements of D (returned in workspace) and
apply or reverse permutation done in TRF.

Look at
lapack_int LAPACKE_dsyconv( int matrix_layout, char uplo, char way, lapack_int n,
double* a, lapack_int lda, const lapack_int* ipiv )

The argument work is omitted and there is no way to get non-diag elements of D.


This is a bug because work array is used to pass off-diagonal elements of matrix D:

Re: LAPACK_?syconv interface problem

PostPosted: Thu Jul 09, 2015 10:58 pm
by admin
Thank you Victor,
This bug has been listed as bug 129 in http://www.netlib.org/lapack/Errata/index2.html
Julie