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RedHat 9 (Linux i386) - man page for zsyrk (redhat section l)

ZSYRK(l)				   BLAS routine 				 ZSYRK(l)

NAME
       ZSYRK - perform one of the symmetric rank k operations	C := alpha*A*A' + beta*C,

SYNOPSIS
       SUBROUTINE ZSYRK ( UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC )

	   CHARACTER*1	UPLO, TRANS

	   INTEGER	N, K, LDA, LDC

	   COMPLEX*16	ALPHA, BETA

	   COMPLEX*16	A( LDA, * ), C( LDC, * )

PURPOSE
       ZSYRK  performs one of the symmetric rank k operations

       or

	  C := alpha*A'*A + beta*C,

       where   alpha and beta  are scalars,  C is an  n by n symmetric matrix and  A  is an  n by
       k  matrix in the first case and a  k by n  matrix in the second case.

PARAMETERS
       UPLO   - 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.

	      Unchanged on exit.

       TRANS  - CHARACTER*1.
	      On entry,  TRANS	specifies the operation to be performed as follows:

	      TRANS = 'N' or 'n'   C := alpha*A*A' + beta*C.

	      TRANS = 'T' or 't'   C := alpha*A'*A + beta*C.

	      Unchanged on exit.

       N      - INTEGER.
	      On  entry,   N  specifies  the  order  of  the  matrix C.  N must be at least zero.
	      Unchanged on exit.

       K      - INTEGER.
	      On entry with  TRANS = 'N' or 'n',  K  specifies	the number of  columns	 of   the
	      matrix	A,   and  on   entry   with TRANS = 'T' or 't',  K  specifies  the number
	      of rows of the matrix A.	K must be at least zero.  Unchanged on exit.

       ALPHA  - COMPLEX*16	.
	      On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.

       A      - 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.
	      Unchanged on exit.

       LDA    - 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 ).  Unchanged on exit.

       BETA   - COMPLEX*16	.
	      On entry, BETA specifies the scalar beta.  Unchanged on exit.

       C      - 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  sym-
	      metric  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  trian-
	      gular part of the 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, n ).  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 Hammar-
	      ling, Numerical Algorithms Group Ltd.

BLAS routine				 16 October 1992				 ZSYRK(l)


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