DSFRK (3) Linux Manual Page

dsfrk.f –

Synopsis

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.

Function/Subroutine Documentation

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.

Author

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