ssyrk.f man page

ssyrk.f —

Synopsis

Functions/Subroutines

subroutine ssyrk (UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC)
SSYRK

Function/Subroutine Documentation

subroutine ssyrk (characterUPLO, characterTRANS, integerN, integerK, realALPHA, real, dimension(lda,*)A, integerLDA, realBETA, real, dimension(ldc,*)C, integerLDC)

SSYRK Purpose:

SSYRK  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.

    TRANS = 'C' or 'c'   C := alpha*A**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   matrix   A,   and  on   entry   with
 TRANS = 'T' or 't' or 'C' or 'c',  K  specifies  the  number
 of rows of the matrix  A.  K must be at least zero.

ALPHA

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

A

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

C

C is REAL 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 170 of file ssyrk.f.

Author

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Referenced By

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

Sat Nov 16 2013 Version 3.4.2 LAPACK