BLAS/SRC/zhemm.f(3) Library Functions Manual BLAS/SRC/zhemm.f(3)

BLAS/SRC/zhemm.f


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

ZHEMM

Purpose:

 ZHEMM  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.

Parameters

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*16
           On entry, ALPHA specifies the scalar alpha.

A

          A is COMPLEX*16 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*16 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*16
           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*16 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 ).

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

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.

Definition at line 190 of file zhemm.f.

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