zsyr2k.f man page

zsyr2k.f —

Synopsis

Functions/Subroutines

subroutine zsyr2k (UPLO, TRANS, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
ZSYR2K

Function/Subroutine Documentation

subroutine zsyr2k (characterUPLO, characterTRANS, integerN, integerK, complex*16ALPHA, complex*16, dimension(lda,*)A, integerLDA, complex*16, dimension(ldb,*)B, integerLDB, complex*16BETA, complex*16, dimension(ldc,*)C, integerLDC)

ZSYR2K Purpose:

ZSYR2K  performs one of the symmetric rank 2k operations

   C := alpha*A*B**T + alpha*B*A**T + beta*C,

or

   C := alpha*A**T*B + alpha*B**T*A + beta*C,

where  alpha and beta  are scalars,  C is an  n by n symmetric 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**T + alpha*B*A**T +
                               beta*C.

    TRANS = 'T' or 't'    C := alpha*A**T*B + alpha*B**T*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 = 'T' or 't',  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 ).

BETA

BETA is COMPLEX*16
 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  symmetric 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  symmetric 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.

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.

Definition at line 189 of file zsyr2k.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

zsyr2k(3) is an alias of zsyr2k.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK