claqsy.f (3) - Linux Manuals
NAME
claqsy.f -
SYNOPSIS
Functions/Subroutines
subroutine claqsy (UPLO, N, A, LDA, S, SCOND, AMAX, EQUED)
CLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.
Function/Subroutine Documentation
subroutine claqsy (characterUPLO, integerN, complex, dimension( lda, * )A, integerLDA, real, dimension( * )S, realSCOND, realAMAX, characterEQUED)
CLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ.
Purpose:
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CLAQSY equilibrates a symmetric matrix A using the scaling factors in the vector S.
Parameters:
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UPLO
UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is stored. = 'U': Upper triangular = 'L': Lower triangular
NN is INTEGER The order of the matrix A. N >= 0.
AA is COMPLEX array, dimension (LDA,N) On entry, the symmetric matrix A. If UPLO = 'U', the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, if EQUED = 'Y', the equilibrated matrix: diag(S) * A * diag(S).
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(N,1).
SS is REAL array, dimension (N) The scale factors for A.
SCONDSCOND is REAL Ratio of the smallest S(i) to the largest S(i).
AMAXAMAX is REAL Absolute value of largest matrix entry.
EQUEDEQUED is CHARACTER*1 Specifies whether or not equilibration was done. = 'N': No equilibration. = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).
Internal Parameters:
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THRESH is a threshold value used to decide if scaling should be done based on the ratio of the scaling factors. If SCOND < THRESH, scaling is done. LARGE and SMALL are threshold values used to decide if scaling should be done based on the absolute size of the largest matrix element. If AMAX > LARGE or AMAX < SMALL, scaling is done.
Author:
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Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
- September 2012
Definition at line 135 of file claqsy.f.
Author
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