Visible to Intel only — GUID: GUID-61B7FF86-D682-4660-87DB-A4AE38A1FB12
Visible to Intel only — GUID: GUID-61B7FF86-D682-4660-87DB-A4AE38A1FB12
?laqhe
Scales a Hermitian matrix.
Syntax
call claqhe( uplo, n, a, lda, s, scond, amax, equed )
call zlaqhe( uplo, n, a, lda, s, scond, amax, equed )
Include Files
- mkl.fi
Description
The routine equilibrates a Hermitian matrix A using the scaling factors in the vector s.
Input Parameters
- uplo
-
CHARACTER*1.
Specifies whether to store the upper or lower part of the Hermitian matrix A.
If uplo = 'U', the upper triangular part of A;
if uplo = 'L', the lower triangular part of A.
- n
-
INTEGER. The order of the matrix A.
n≥ 0.
- a
-
COMPLEX for claqhe
DOUBLE COMPLEX for zlaqhe
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 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 matrix A and the strictly upper triangular part of a is not referenced.
- lda
-
INTEGER. The leading dimension of the array a.
lda≥ max(n,1).
- s
-
REAL for claqhe
DOUBLE PRECISION for zlaqhe
Array, DIMENSION (n). The scale factors for A.
- scond
-
REAL for claqhe
DOUBLE PRECISION for zlaqhe
Ratio of the smallest s(i) to the largest s(i).
- amax
-
REAL for claqhe
DOUBLE PRECISION for zlaqhe
Absolute value of largest matrix entry.
Output Parameters
- a
-
If equed = 'Y', a contains the equilibrated matrix diag(s)*A*diag(s).
- equed
-
CHARACTER*1.
Specifies whether or not equilibration was done.
If equed = 'N': No equilibration.
If equed = 'Y': Equilibration was done, that is, A has been replaced by diag(s)*A*diag(s).
Application Notes
The routine uses internal parameters thresh, large, and small. The parameter 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.
The large and small parameters 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.