dsyr2k(3P) Sun Performance Library dsyr2k(3P)NAMEdsyr2k - perform one of the symmetric rank 2k operations C :=
alpha*A*B' + alpha*B*A' + beta*C or C := alpha*A'*B + alpha*B'*A +
beta*C
SYNOPSIS
SUBROUTINE DSYR2K(UPLO, TRANSA, N, K, ALPHA, A, LDA, B, LDB, BETA, C,
LDC)
CHARACTER * 1 UPLO, TRANSA
INTEGER N, K, LDA, LDB, LDC
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION A(LDA,*), B(LDB,*), C(LDC,*)
SUBROUTINE DSYR2K_64(UPLO, TRANSA, N, K, ALPHA, A, LDA, B, LDB, BETA,
C, LDC)
CHARACTER * 1 UPLO, TRANSA
INTEGER*8 N, K, LDA, LDB, LDC
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION A(LDA,*), B(LDB,*), C(LDC,*)
F95 INTERFACE
SUBROUTINE SYR2K(UPLO, [TRANSA], [N], [K], ALPHA, A, [LDA], B, [LDB],
BETA, C, [LDC])
CHARACTER(LEN=1) :: UPLO, TRANSA
INTEGER :: N, K, LDA, LDB, LDC
REAL(8) :: ALPHA, BETA
REAL(8), DIMENSION(:,:) :: A, B, C
SUBROUTINE SYR2K_64(UPLO, [TRANSA], [N], [K], ALPHA, A, [LDA], B,
[LDB], BETA, C, [LDC])
CHARACTER(LEN=1) :: UPLO, TRANSA
INTEGER(8) :: N, K, LDA, LDB, LDC
REAL(8) :: ALPHA, BETA
REAL(8), DIMENSION(:,:) :: A, B, C
C INTERFACE
#include <sunperf.h>
void dsyr2k(char uplo, char transa, int n, int k, double alpha, double
*a, int lda, double *b, int ldb, double beta, double *c, int
ldc);
void dsyr2k_64(char uplo, char transa, long n, long k, double alpha,
double *a, long lda, double *b, long ldb, double beta, double
*c, long ldc);
PURPOSEdsyr2k performs one of the symmetric rank 2k operations C := alpha*A*B'
+ alpha*B*A' + beta*C or C := alpha*A'*B + alpha*B'*A + beta*C where
alpha and beta are scalars, C is an n by n symmetric matrix and A
and B are n by k matrices in the first case and k by n matrices
in the second case.
ARGUMENTS
UPLO (input)
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.
TRANSA (input)
On entry, TRANSA specifies the operation to be performed as
follows:
TRANSA = 'N' or 'n' C := alpha*A*B' + alpha*B*A' + beta*C.
TRANSA = 'T' or 't' C := alpha*A'*B + alpha*B'*A + beta*C.
TRANSA = 'C' or 'c' C := alpha*A'*B + alpha*B'*A + beta*C.
Unchanged on exit.
TRANSA is defaulted to 'N' for F95 INTERFACE.
N (input)
On entry, N specifies the order of the matrix C. N must be
at least zero. Unchanged on exit.
K (input)
On entry with TRANSA = 'N' or 'n', K specifies the number
of columns of the matrices A and B, and on entry with
TRANSA = 'T' or 't' or 'C' or 'c', K specifies the number
of rows of the matrices A and B. K must be at least zero.
Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha. Unchanged on
exit.
A (input)
DOUBLE PRECISION array of DIMENSION ( LDA, ka ), where ka is
k when TRANSA = 'N' or 'n', and is n otherwise. Before
entry with TRANSA = '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)
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. When TRANSA = 'N' or 'n'
then LDA must be at least max( 1, n ), otherwise LDA must
be at least max( 1, k ). Unchanged on exit.
B (input)
DOUBLE PRECISION array of DIMENSION ( LDB, kb ), where kb is
k when TRANSA = 'N' or 'n', and is n otherwise. Before
entry with TRANSA = 'N' or 'n', the leading n by k part
of the array B must contain the matrix B, otherwise the
leading k by n part of the array B must contain the
matrix B. Unchanged on exit.
LDB (input)
On entry, LDB specifies the first dimension of B as declared
in the calling (sub) program. When TRANSA = 'N' or 'n'
then LDB must be at least max( 1, n ), otherwise LDB must
be at least max( 1, k ). Unchanged on exit.
BETA (input)
On entry, BETA specifies the scalar beta. Unchanged on exit.
C (input/output)
DOUBLE PRECISION array of DIMENSION ( LDC, n ).
Before entry with UPLO = 'U' or 'u', the leading n by n
upper triangular part of the array C must contain the upper
triangular part of the symmetric matrix and the strictly
lower triangular part of C is not referenced. On exit, the
upper triangular part of the array C is overwritten by the
upper triangular part of the updated matrix.
Before entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array C must contain the lower
triangular part of the symmetric matrix and the strictly
upper triangular part of C is not referenced. On exit, the
lower triangular part of the array C is overwritten by the
lower triangular part of the updated matrix.
LDC (input)
On entry, LDC specifies the first dimension of C as declared
in the calling (sub) program. LDC must be at least
max( 1, n ). Unchanged on exit.
6 Mar 2009 dsyr2k(3P)
