![]() |
LAPACK
3.7.0
LAPACK: Linear Algebra PACKage
|
subroutine zlaqhe | ( | character | UPLO, |
integer | N, | ||
complex*16, dimension( lda, * ) | A, | ||
integer | LDA, | ||
double precision, dimension( * ) | S, | ||
double precision | SCOND, | ||
double precision | AMAX, | ||
character | EQUED | ||
) |
ZLAQHE scales a Hermitian matrix.
Download ZLAQHE + dependencies [TGZ] [ZIP] [TXT]
ZLAQHE equilibrates a Hermitian matrix A using the scaling factors in the vector S.
[in] | UPLO | UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix A is stored. = 'U': Upper triangular = 'L': Lower triangular |
[in] | N | N is INTEGER The order of the matrix A. N >= 0. |
[in,out] | A | A is COMPLEX*16 array, dimension (LDA,N) On entry, the Hermitian 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). |
[in] | LDA | LDA is INTEGER The leading dimension of the array A. LDA >= max(N,1). |
[in] | S | S is DOUBLE PRECISION array, dimension (N) The scale factors for A. |
[in] | SCOND | SCOND is DOUBLE PRECISION Ratio of the smallest S(i) to the largest S(i). |
[in] | AMAX | AMAX is DOUBLE PRECISION Absolute value of largest matrix entry. |
[out] | 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 = 'Y': Equilibration was done, i.e., A has been replaced by diag(S) * A * diag(S). |
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.
Definition at line 136 of file zlaqhe.f.