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NAME
CHEMM - perform one of the matrix-matrix operations C :=
alpha*A*B + beta*C,
SYNOPSIS
SUBROUTINE CHEMM ( SIDE, UPLO, M, N, ALPHA, A, LDA, B, LDB,
BETA, C, LDC )
CHARACTER*1 SIDE, UPLO
INTEGER M, N, LDA, LDB, LDC
COMPLEX ALPHA, BETA
COMPLEX A( LDA, * ), B( LDB, * ), C( LDC, * )
PURPOSE
CHEMM performs one of the matrix-matrix operations
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.
PARAMETERS
SIDE - 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,
Unchanged on exit.
UPLO - 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.
Unchanged on exit.
M - INTEGER.
On entry, M specifies the number of rows of the
matrix C. M must be at least zero. Unchanged on
exit.
N - INTEGER.
On entry, N specifies the number of columns of the
matrix C. N must be at least zero. Unchanged on
exit.
ALPHA - COMPLEX .
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
ka is
A -
COMPLEX array of DIMENSION ( LDA, ka ), where
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 lead-
ing m by m upper triangular part of the array A
must contain the upper triangular part of the hermi-
tian 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 lead-
ing n by n upper triangular part of the array A
must contain the upper triangular part of the hermi-
tian 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.
Unchanged on exit.
LDA - 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 ).
Unchanged on exit.
B - COMPLEX array of DIMENSION ( LDB, n ).
Before entry, the leading m by n part of the array
B must contain the matrix B. Unchanged on exit.
LDB - 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 ). Unchanged on exit.
BETA - COMPLEX .
On entry, BETA specifies the scalar beta. When
BETA is supplied as zero then C need not be set on
input. Unchanged on exit.
C - COMPLEX array of 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 - 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 ). Unchanged on exit.
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.