zher2k.f(3)

NAME
zher2k.f -

SYNOPSIS

  Functions/Subroutines
subroutine zher2k (UPLO, TRANS, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
ZHER2K

Function/Subroutine Documentation

  subroutine zher2k (characterUPLO, characterTRANS, integerN, integerK, complex*16ALPHA, complex*16, dimension(lda,*)A, integerLDA, complex*16, dimension(ldb,*)B, integerLDB, double precisionBETA, complex*16, dimension(ldc,*)C, integerLDC)

ZHER2K Purpose:

     ZHER2K  performs one of the hermitian rank 2k operations
        C := alpha*A*B**H + conjg( alpha )*B*A**H + beta*C,
     or
        C := alpha*A**H*B + conjg( alpha )*B**H*A + beta*C,
     where  alpha and beta  are scalars with  beta  real,  C is an  n by n
     hermitian matrix and  A and B  are  n by k matrices in the first case
     and  k by n  matrices in the second case.

Parameters:
    UPLO

              UPLO is CHARACTER*1
               On  entry,   UPLO  specifies  whether  the  upper  or  lower
               triangular  part  of the  array  C  is to be  referenced  as
               follows:
                  UPLO = 'U' or 'u'   Only the  upper triangular part of  C
                                      is to be referenced.
                  UPLO = 'L' or 'l'   Only the  lower triangular part of  C
                                      is to be referenced.

    TRANS

              TRANS is CHARACTER*1
               On entry,  TRANS  specifies the operation to be performed as
               follows:
                  TRANS = 'N' or 'n'    C := alpha*A*B**H          +
                                             conjg( alpha )*B*A**H +
                                             beta*C.
                  TRANS = 'C' or 'c'    C := alpha*A**H*B          +
                                             conjg( alpha )*B**H*A +
                                             beta*C.

    N

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

    K

              K is INTEGER
               On entry with  TRANS = 'N' or 'n',  K  specifies  the number
               of  columns  of the  matrices  A and B,  and on  entry  with
               TRANS = 'C' or 'c',  K  specifies  the number of rows of the
               matrices  A and B.  K must be at least zero.

    ALPHA

              ALPHA is COMPLEX*16 .
               On entry, ALPHA specifies the scalar alpha.

    A

              A is COMPLEX*16 array of DIMENSION ( LDA, ka ), where ka is
               k  when  TRANS = 'N' or 'n',  and is  n  otherwise.
               Before entry with  TRANS = 'N' or 'n',  the  leading  n by k
               part of the array  A  must contain the matrix  A,  otherwise
               the leading  k by n  part of the array  A  must contain  the
               matrix A.

    LDA

              LDA is INTEGER
               On entry, LDA specifies the first dimension of A as declared
               in  the  calling  (sub)  program.   When  TRANS = 'N' or 'n'
               then  LDA must be at least  max( 1, n ), otherwise  LDA must
               be at least  max( 1, k ).

    B

              B is COMPLEX*16 array of DIMENSION ( LDB, kb ), where kb is
               k  when  TRANS = 'N' or 'n',  and is  n  otherwise.
               Before entry with  TRANS = 'N' or 'n',  the  leading  n by k
               part of the array  B  must contain the matrix  B,  otherwise
               the leading  k 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.   When  TRANS = 'N' or 'n'
               then  LDB must be at least  max( 1, n ), otherwise  LDB must
               be at least  max( 1, k ).
               Unchanged on exit.

    BETA

              BETA is DOUBLE PRECISION .
               On entry, BETA specifies the scalar beta.

    C

              C is COMPLEX*16 array of DIMENSION ( LDC, n ).
               Before entry  with  UPLO = 'U' or 'u',  the leading  n by n
               upper triangular part of the array C must contain the upper
               triangular part  of the  hermitian matrix  and the strictly
               lower triangular part of C is not referenced.  On exit, the
               upper triangular part of the array  C is overwritten by the
               upper triangular part of the updated matrix.
               Before entry  with  UPLO = 'L' or 'l',  the leading  n by n
               lower triangular part of the array C must contain the lower
               triangular part  of the  hermitian matrix  and the strictly
               upper triangular part of C is not referenced.  On exit, the
               lower triangular part of the array  C is overwritten by the
               lower triangular part of the updated matrix.
               Note that the imaginary parts of the diagonal elements need
               not be set,  they are assumed to be zero,  and on exit they
               are set to zero.

    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, n ).

Author:
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Date:
    November 2011

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.
      -- Modified 8-Nov-93 to set C(J,J) to DBLE( C(J,J) ) when BETA = 1.
         Ed Anderson, Cray Research Inc.

Definition at line 199 of file zher2k.f.

Author

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