SSFRK(1)LAPACK routine (version 3.2) SSFRK(1)NAME
SSFRK - 3 BLAS like routine for C in RFP Format
SYNOPSIS
SUBROUTINE SSFRK( TRANSR, UPLO, TRANS, N, K, ALPHA, A, LDA, BETA,
+ C )
REAL ALPHA, BETA
INTEGER K, LDA, N
CHARACTER TRANS, TRANSR, UPLO
REAL A( LDA, * ), C( * )
PURPOSE
Level 3 BLAS like routine for C in RFP Format. SSFRK performs one of
the symmetric rank--k operations
C := alpha*A*A' + beta*C,
or
C := alpha*A'*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.
ARGUMENTS
TRANSR (input) CHARACTER
= 'N': The Normal Form of RFP A is stored;
= 'T': The Transpose Form of RFP A is stored.
UPLO - (input) CHARACTER
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 refer‐
enced. UPLO = 'L' or 'l' Only the lower triangular part of C
is to be referenced. Unchanged on exit.
TRANS - (input) CHARACTER
On entry, TRANS specifies the operation to be performed as fol‐
lows: TRANS = 'N' or 'n' C := alpha*A*A' + beta*C. TRANS =
'T' or 't' C := alpha*A'*A + beta*C. Unchanged on exit.
N - (input) INTEGER.
On entry, N specifies the order of the matrix C. N must be at
least zero. Unchanged on exit.
K - (input) 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 - (input) REAL.
On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
A - (input) 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. Unchanged on exit.
LDA - (input) 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 - (input) REAL.
On entry, BETA specifies the scalar beta. Unchanged on exit.
C - (input/output) 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.
ARGUMENTS
LAPACK routine (version 3.2) November 2008 SSFRK(1)
