redhat man page for dlaqsb

Query: dlaqsb

OS: redhat

Section: l

Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar

DLAQSB(l)								 )								 DLAQSB(l)

NAME
DLAQSB - equilibrate a symmetric band matrix A using the scaling factors in the vector S
SYNOPSIS
SUBROUTINE DLAQSB( UPLO, N, KD, AB, LDAB, S, SCOND, AMAX, EQUED ) CHARACTER EQUED, UPLO INTEGER KD, LDAB, N DOUBLE PRECISION AMAX, SCOND DOUBLE PRECISION AB( LDAB, * ), S( * )
PURPOSE
DLAQSB equilibrates a symmetric band matrix A using the scaling factors in the vector S.
ARGUMENTS
UPLO (input) CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix A is stored. = 'U': Upper triangular = 'L': Lower triangular N (input) INTEGER The order of the matrix A. N >= 0. KD (input) INTEGER The number of super-diagonals of the matrix A if UPLO = 'U', or the number of sub-diagonals if UPLO = 'L'. KD >= 0. AB (input/output) DOUBLE PRECISION array, dimension (LDAB,N) On entry, the upper or lower triangle of the symmetric band matrix A, stored in the first KD+1 rows of the array. The j-th column of A is stored in the j-th column of the array AB as follows: if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). On exit, if INFO = 0, the triangular factor U or L from the Cholesky factorization A = U'*U or A = L*L' of the band matrix A, in the same storage format as A. LDAB (input) INTEGER The leading dimension of the array AB. LDAB >= KD+1. S (output) DOUBLE PRECISION array, dimension (N) The scale factors for A. SCOND (input) DOUBLE PRECISION Ratio of the smallest S(i) to the largest S(i). AMAX (input) DOUBLE PRECISION Absolute value of largest matrix entry. EQUED (output) 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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S).
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. LAPACK version 3.0 15 June 2000 DLAQSB(l)
Related Man Pages
claqsb(l) - redhat
dlaqsp(l) - redhat
dlaqsy(l) - redhat
slaqsb(l) - redhat
zlaqsy(l) - redhat
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