C Library Functions - chemm (3)

NAME

chemm(3f) - [BLAS:COMPLEX_BLAS_LEVEL3] C:=alpha*A*TRANSPOSE(A)+beta*C; ==> A hermitian, B, C rectangular.

Synopsis
Definition
Options
C
Authors
Further Details
See Also

SYNOPSIS

subroutine chemm(side,uplo,m,n,alpha,a,lda,b,ldb,beta,c,ldc)

      .. Scalar Arguments ..
      complex,intent(in)    :: alpha,beta
      integer,intent(in)    :: lda,ldb,ldc,m,n
      character,intent(in)  :: side,uplo
      ..
      .. Array Arguments ..
      complex,intent(in)    :: a(lda,*),b(ldb,*)
      complex,intent(inout) :: c(ldc,*)
      ..

DEFINITION

CHEMM performs one of the matrix-matrix operations
    C := alpha*A*B + beta*C,
or
    C := alpha*B*A + beta*C,
where alpha and beta are scalars, A is an hermitian matrix and B and C are m by n matrices.

OPTIONS

SIDE

SIDE is CHARACTER*1 On entry, SIDE specifies whether the hermitian matrix A appears on the left or right in the operation as follows:
              SIDE = ’L’ or ’l’   C := alpha*A*B + beta*C,

              SIDE = ’R’ or ’r’   C := alpha*B*A + beta*C,

UPLO

UPLO is CHARACTER*1 On entry, UPLO specifies whether the upper or lower triangular part of the hermitian matrix A is to be referenced as follows:

UPLO = ’U’ or ’u’ Only the upper triangular part of the hermitian matrix is to be referenced.

UPLO = ’L’ or ’l’ Only the lower triangular part of the hermitian matrix is to be referenced.

M

M is INTEGER On entry, M specifies the number of rows of the matrix C. M must be at least zero.

N

N is INTEGER On entry, N specifies the number of columns of the matrix C. N must be at least zero.

ALPHA

ALPHA is COMPLEX On entry, ALPHA specifies the scalar alpha.

A

A is COMPLEX array, dimension ( LDA, ka ), where ka is m when SIDE = ’L’ or ’l’ and is n otherwise. Before entry with SIDE = ’L’ or ’l’, the m by m part of the array A must contain the hermitian matrix, such that when UPLO = ’U’ or ’u’, the leading m by m upper triangular part of the array A must contain the upper triangular part of the hermitian matrix and the strictly lower triangular part of A is not referenced, and when UPLO = ’L’ or ’l’, the leading m by m lower triangular part of the array A must contain the lower triangular part of the hermitian matrix and the strictly upper triangular part of A is not referenced. Before entry with SIDE = ’R’ or ’r’, the n by n part of the array A must contain the hermitian matrix, such that when UPLO = ’U’ or ’u’, the leading n by n upper triangular part of the array A must contain the upper triangular part of the hermitian matrix and the strictly lower triangular part of A is not referenced, and when UPLO = ’L’ or ’l’, the leading n by n lower triangular part of the array A must contain the lower triangular part of the hermitian matrix and the strictly upper triangular part of A is not referenced. Note that the imaginary parts of the diagonal elements need not be set, they are assumed to be zero.

LDA

LDA is INTEGER On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. When SIDE = ’L’ or ’l’ then LDA must be at least max( 1, m ), otherwise LDA must be at least max( 1, n ).

B

B is COMPLEX array, dimension ( LDB, N ) Before entry, the leading m by n part of the array B must contain the matrix B.

LDB

LDB is INTEGER On entry, LDB specifies the first dimension of B as declared in the calling (sub) program. LDB must be at least max( 1, m ).

BETA

BETA is COMPLEX On entry, BETA specifies the scalar beta. When BETA is supplied as zero then C need not be set on input.

C

C is COMPLEX array, dimension ( LDC, N ) Before entry, the leading m by n part of the array C must contain the matrix C, except when beta is zero, in which case C need not be set on entry. On exit, the array C is overwritten by the m by n updated matrix.

LDC

LDC is INTEGER On entry, LDC specifies the first dimension of C as declared in the calling (sub) program. LDC must be at least max( 1, m ).

AUTHORS

o Univ. of Tennessee

o Univ. of California Berkeley

o Univ. of Colorado Denver

o NAG Ltd.
 date:December 2016

FURTHER DETAILS

Level 3 Blas routine.
-- Written on 8-February-1989. Jack Dongarra, Argonne National Laboratory. Iain Duff, AERE Harwell. Jeremy Du Croz, Numerical Algorithms Group Ltd. Sven Hammarling, Numerical Algorithms Group Ltd.