Contents
dsyr2k - 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
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, dou-
ble alpha, double *a, long lda, double *b, long
ldb, double beta, double *c, long ldc);
dsyr2k 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.
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 lead-
ing n by n upper triangular part of the array C
must contain the upper triangular part of the
symmetric matrix and the strictly lower triangu-
lar part of C is not referenced. On exit, the
upper triangular part of the array C is overwrit-
ten by the upper triangular part of the updated
matrix.
Before entry with UPLO = 'L' or 'l', the lead-
ing n by n lower triangular part of the array C
must contain the lower triangular part of the
symmetric matrix and the strictly upper triangu-
lar part of C is not referenced. On exit, the
lower triangular part of the array C is overwrit-
ten 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.