dtrsm(3P) Sun Performance Library dtrsm(3P)NAMEdtrsm - solve one of the matrix equations op( A )*X = alpha*B, or
X*op( A ) = alpha*B
SYNOPSIS
SUBROUTINE DTRSM(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B,
LDB)
CHARACTER * 1 SIDE, UPLO, TRANSA, DIAG
INTEGER M, N, LDA, LDB
DOUBLE PRECISION ALPHA
DOUBLE PRECISION A(LDA,*), B(LDB,*)
SUBROUTINE DTRSM_64(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B,
LDB)
CHARACTER * 1 SIDE, UPLO, TRANSA, DIAG
INTEGER*8 M, N, LDA, LDB
DOUBLE PRECISION ALPHA
DOUBLE PRECISION A(LDA,*), B(LDB,*)
F95 INTERFACE
SUBROUTINE TRSM(SIDE, UPLO, [TRANSA], DIAG, [M], [N], ALPHA, A, [LDA],
B, [LDB])
CHARACTER(LEN=1) :: SIDE, UPLO, TRANSA, DIAG
INTEGER :: M, N, LDA, LDB
REAL(8) :: ALPHA
REAL(8), DIMENSION(:,:) :: A, B
SUBROUTINE TRSM_64(SIDE, UPLO, [TRANSA], DIAG, [M], [N], ALPHA, A,
[LDA], B, [LDB])
CHARACTER(LEN=1) :: SIDE, UPLO, TRANSA, DIAG
INTEGER(8) :: M, N, LDA, LDB
REAL(8) :: ALPHA
REAL(8), DIMENSION(:,:) :: A, B
C INTERFACE
#include <sunperf.h>
void dtrsm(char side, char uplo, char transa, char diag, int m, int n,
double alpha, double *a, int lda, double *b, int ldb);
void dtrsm_64(char side, char uplo, char transa, char diag, long m,
long n, double alpha, double *a, long lda, double *b, long
ldb);
PURPOSEdtrsm solves one of the matrix equations op( A )*X = alpha*B, or X*op(
A ) = alpha*B where alpha is a scalar, X and B are m by n matrices, A
is a unit, or non-unit, upper or lower triangular matrix and op( A )
is one of
op( A ) = A or op( A ) = A'.
The matrix X is overwritten on B.
ARGUMENTS
SIDE (input)
On entry, SIDE specifies whether op( A ) appears on the left
or right of X as follows:
SIDE = 'L' or 'l' op( A )*X = alpha*B.
SIDE = 'R' or 'r' X*op( A ) = alpha*B.
Unchanged on exit.
UPLO (input)
On entry, UPLO specifies whether the matrix A is an upper or
lower triangular matrix as follows:
UPLO = 'U' or 'u' A is an upper triangular matrix.
UPLO = 'L' or 'l' A is a lower triangular matrix.
Unchanged on exit.
TRANSA (input)
On entry, TRANSA specifies the form of op( A ) to be used in
the matrix multiplication as follows:
TRANSA = 'N' or 'n' op( A ) = A.
TRANSA = 'T' or 't' op( A ) = A'.
TRANSA = 'C' or 'c' op( A ) = A'.
Unchanged on exit.
TRANSA is defaulted to 'N' for F95 INTERFACE.
DIAG (input)
On entry, DIAG specifies whether or not A is unit triangular
as follows:
DIAG = 'U' or 'u' A is assumed to be unit triangular.
DIAG = 'N' or 'n' A is not assumed to be unit triangular.
Unchanged on exit.
M (input)
On entry, M specifies the number of rows of B. M >= 0.
Unchanged on exit.
N (input)
On entry, N specifies the number of columns of B. N >= 0.
Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha. When alpha is
zero then A is not referenced and B need not be set before
entry. Unchanged on exit.
A (input)
DOUBLE PRECISION array of DIMENSION ( LDA, k ), where k is m
when SIDE = 'L' or 'l' and is n when SIDE = 'R' or 'r'.
Before entry with UPLO = 'U' or 'u', the leading k by k
upper triangular part of the array A must contain the upper
triangular matrix and the strictly lower triangular part of
A is not referenced.
Before entry with UPLO = 'L' or 'l', the leading k by k
lower triangular part of the array A must contain the lower
triangular matrix and the strictly upper triangular part of
A is not referenced.
Note that when DIAG = 'U' or 'u', the diagonal elements of A
are not referenced either, but are assumed to be one.
Unchanged on exit.
LDA (input)
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. When SIDE = 'L' or 'l' then
LDA >= max( 1, m ), when SIDE = 'R' or 'r' then LDA >= max(
1, n ). Unchanged on exit.
B (input/output)
DOUBLE PRECISION array of DIMENSION ( LDB, n ). Before
entry, the leading m by n part of the array B must contain
the right-hand side matrix B, and on exit is overwrit‐
ten by the solution matrix X.
LDB (input)
On entry, LDB specifies the first dimension of B as declared
in the calling (sub) program. LDB >= max( 1, m ).
Unchanged on exit.
6 Mar 2009 dtrsm(3P)
