csyrk-f(3)

csyrk.f –

Synopsis

Functions/Subroutines

subroutine csyrk (UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC)
CSYRK

Function/Subroutine Documentation

subroutine csyrk (characterUPLO, characterTRANS, integerN, integerK, complexALPHA, complex, dimension(lda,)A, integerLDA, complexBETA, complex, dimension(ldc,)C, integerLDC)

CSYRK Purpose:

 CSYRK performs one of the symmetric rank k operations
 C := alpha*A*A**T + beta*C,
 or
 C := alpha*A**T*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

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

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

 K is 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.

ALPHA

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

 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 ).

BETA

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

 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 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 168 of file csyrk.f.

Author