CHER2K

cher2k.f(3)                         LAPACK                         cher2k.f(3)



NAME
       cher2k.f -

SYNOPSIS
   Functions/Subroutines
       subroutine cher2k (UPLO, TRANS, N, K, ALPHA, A, LDA, B, LDB, BETA, C,
           LDC)
           CHER2K

Function/Subroutine Documentation
   subroutine cher2k (characterUPLO, characterTRANS, integerN, integerK,
       complexALPHA, complex, dimension(lda,*)A, integerLDA, complex,
       dimension(ldb,*)B, integerLDB, realBETA, complex, dimension(ldc,*)C,
       integerLDC)
       CHER2K Purpose:


            CHER2K  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
                      On entry, ALPHA specifies the scalar alpha.

           A

                     A is COMPLEX 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 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 ).

           BETA

                     BETA is REAL
                      On entry, BETA specifies the scalar beta.

           C

                     C is COMPLEX 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 REAL( C(J,J) ) when BETA = 1.
                Ed Anderson, Cray Research Inc.

       Definition at line 198 of file cher2k.f.

Author
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Version 3.4.2                   Tue Sep 25 2012                    cher2k.f(3)