DSFRK
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.
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.
Arguments
| TRANSR |
(input) CHARACTER*1
= 'N': The Normal Form of RFP A is stored;
= 'T': The Transpose Form of RFP A is stored. |
| UPLO |
(input) 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 |
(input) 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 |
(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) DOUBLE PRECISION
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit. |
| A |
(input) 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 |
(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) DOUBLE PRECISION
On entry, BETA specifies the scalar beta.
Unchanged on exit. |
| C |
(input/output) 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. |