DragonFly On-Line Manual Pages

Search: Section:  


slaqsy.f(3)                         LAPACK                         slaqsy.f(3)

NAME

slaqsy.f -

SYNOPSIS

Functions/Subroutines subroutine slaqsy (UPLO, N, A, LDA, S, SCOND, AMAX, EQUED) SLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ. Function/Subroutine Documentation subroutine slaqsy (characterUPLO, integerN, real, dimension( lda, * )A, integerLDA, real, dimension( * )S, realSCOND, realAMAX, characterEQUED) SLAQSY scales a symmetric/Hermitian matrix, using scaling factors computed by spoequ. Purpose: SLAQSY equilibrates a symmetric matrix A using the scaling factors in the vector S. Parameters: 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 N N is INTEGER The order of the matrix A. N >= 0. A A is REAL 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). LDA LDA is INTEGER The leading dimension of the array A. LDA >= max(N,1). S S is REAL array, dimension (N) The scale factors for A. SCOND SCOND is REAL Ratio of the smallest S(i) to the largest S(i). AMAX AMAX is REAL Absolute value of largest matrix entry. EQUED EQUED 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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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: 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: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 134 of file slaqsy.f. Author Generated automatically by Doxygen for LAPACK from the source code. Version 3.4.2 Sat Nov 16 2013 slaqsy.f(3)

Search: Section: