ssfrk.f - Man Page

subroutine ssfrk (transr, uplo, trans, n, k, alpha, a, lda, beta, c)
SSFRK performs a symmetric rank-k operation for matrix in RFP format.

SSFRK performs a symmetric rank-k operation for matrix in RFP format.  

Purpose:

 Level 3 BLAS like routine for C in RFP Format.

 SSFRK 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 real 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

TRANSR

          TRANSR is CHARACTER*1
          = 'N':  The Normal Form of RFP A is stored;
          = 'T':  The Transpose Form of RFP A is stored.

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.

           Unchanged on exit.

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.

           Unchanged on exit.

N

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

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', K specifies the number of rows of the matrix A. K
           must be at least zero.
           Unchanged on exit.

ALPHA

          ALPHA is REAL
           On entry, ALPHA specifies the scalar alpha.
           Unchanged on exit.

A

          A is REAL array, 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

          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 ).
           Unchanged on exit.

BETA

          BETA is REAL
           On entry, BETA specifies the scalar beta.
           Unchanged on exit.

C

          C is REAL array, dimension (NT)
           NT = N*(N+1)/2. On entry, the symmetric matrix C in RFP
           Format. RFP Format is described by TRANSR, UPLO and N.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 164 of file ssfrk.f.