Provided by: liblapack-doc-man_3.5.0-2ubuntu1_all
NAME
dlaqsp.f -
SYNOPSIS
Functions/Subroutines subroutine dlaqsp (UPLO, N, AP, S, SCOND, AMAX, EQUED) DLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ.
Function/Subroutine Documentation
subroutine dlaqsp (characterUPLO, integerN, double precision, dimension( * )AP, double precision, dimension( * )S, double precisionSCOND, double precisionAMAX, characterEQUED) DLAQSP scales a symmetric/Hermitian matrix in packed storage, using scaling factors computed by sppequ. Purpose: DLAQSP 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. AP AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) On entry, the upper or lower triangle of the symmetric matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. On exit, the equilibrated matrix: diag(S) * A * diag(S), in the same storage format as A. S S is DOUBLE PRECISION array, dimension (N) The scale factors for A. SCOND SCOND is DOUBLE PRECISION Ratio of the smallest S(i) to the largest S(i). AMAX AMAX is DOUBLE PRECISION 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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).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 126 of file dlaqsp.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.