Contents
strsv - solve one of the systems of equations A*x = b, or
A'*x = b
SUBROUTINE STRSV(UPLO, TRANSA, DIAG, N, A, LDA, Y, INCY)
CHARACTER * 1 UPLO, TRANSA, DIAG
INTEGER N, LDA, INCY
REAL A(LDA,*), Y(*)
SUBROUTINE STRSV_64(UPLO, TRANSA, DIAG, N, A, LDA, Y, INCY)
CHARACTER * 1 UPLO, TRANSA, DIAG
INTEGER*8 N, LDA, INCY
REAL A(LDA,*), Y(*)
F95 INTERFACE
SUBROUTINE TRSV(UPLO, [TRANSA], DIAG, [N], A, [LDA], Y, [INCY])
CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
INTEGER :: N, LDA, INCY
REAL, DIMENSION(:) :: Y
REAL, DIMENSION(:,:) :: A
SUBROUTINE TRSV_64(UPLO, [TRANSA], DIAG, [N], A, [LDA], Y, [INCY])
CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
INTEGER(8) :: N, LDA, INCY
REAL, DIMENSION(:) :: Y
REAL, DIMENSION(:,:) :: A
C INTERFACE
#include <sunperf.h>
void strsv(char uplo, char transa, char diag, int n, float
*a, int lda, float *y, int incy);
void strsv_64(char uplo, char transa, char diag, long n,
float *a, long lda, float *y, long incy);
strsv solves one of the systems of equations A*x = b, or
A'*x = b, where b and x are n element vectors and A is an n
by n unit, or non-unit, upper or lower triangular matrix.
No test for singularity or near-singularity is included in
this routine. Such tests must be performed before calling
this routine.
UPLO (input)
On entry, UPLO specifies whether the matrix 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 equations to be
solved as follows:
TRANSA = 'N' or 'n' A*x = b.
TRANSA = 'T' or 't' A'*x = b.
TRANSA = 'C' or 'c' A'*x = b.
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 tri-
angular.
DIAG = 'N' or 'n' A is not assumed to be unit
triangular.
Unchanged on exit.
N (input)
On entry, N specifies the order of the matrix A.
N >= 0. Unchanged on exit.
A (input)
Before entry with UPLO = 'U' or 'u', the leading
n by n upper triangular part of the array A must
contain the upper triangular matrix and the
strictly lower triangular part of A is not refer-
enced. Before entry with UPLO = 'L' or 'l', the
leading n by n lower triangular part of the array
A must contain the lower triangular matrix and the
strictly upper triangular part of A is not refer-
enced. Note that when DIAG = 'U' or 'u', the
diagonal elements of A are not referenced either,
but are assumed to be unity. Unchanged on exit.
LDA (input)
On entry, LDA specifies the first dimension of A
as declared in the calling (sub) program. LDA >=
max( 1, n ). Unchanged on exit.
Y (input/output)
( 1 + ( n - 1 )*abs( INCY ) ). Before entry, the
incremented array Y must contain the n element
right-hand side vector b. On exit, Y is overwrit-
ten with the solution vector x.
INCY (input)
On entry, INCY specifies the increment for the
elements of Y. INCY <> 0. Unchanged on exit.