dsfrk (3)

Functions/Subroutines

subroutine dsfrk (TRANSR, UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C)

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

subroutine dsfrk (characterTRANSR, characterUPLO, characterTRANS, integerN, integerK, double precisionALPHA, double precision, dimension( lda, * )A, integerLDA, double precisionBETA, double precision, dimension( * )C)

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

Purpose:

 Level 3 BLAS like routine for C in RFP Format.

 DSFRK 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 DOUBLE PRECISION
           On entry, ALPHA specifies the scalar alpha.
           Unchanged on exit.

A

          A is DOUBLE PRECISION 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 DOUBLE PRECISION
           On entry, BETA specifies the scalar beta.
           Unchanged on exit.

C

          C is DOUBLE PRECISION 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.

Date:

September 2012

Definition at line 166 of file dsfrk.f.

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