dtptrs - solve a triangular system of the form A * X = B or A**T * X = B,
SUBROUTINE DTPTRS( UPLO, TRANSA, DIAG, N, NRHS, A, B, LDB, INFO) CHARACTER * 1 UPLO, TRANSA, DIAG INTEGER N, NRHS, LDB, INFO DOUBLE PRECISION A(*), B(LDB,*)
SUBROUTINE DTPTRS_64( UPLO, TRANSA, DIAG, N, NRHS, A, B, LDB, INFO) CHARACTER * 1 UPLO, TRANSA, DIAG INTEGER*8 N, NRHS, LDB, INFO DOUBLE PRECISION A(*), B(LDB,*)
SUBROUTINE TPTRS( UPLO, TRANSA, DIAG, N, [NRHS], A, B, [LDB], [INFO]) CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG INTEGER :: N, NRHS, LDB, INFO REAL(8), DIMENSION(:) :: A REAL(8), DIMENSION(:,:) :: B
SUBROUTINE TPTRS_64( UPLO, TRANSA, DIAG, N, [NRHS], A, B, [LDB], * [INFO]) CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG INTEGER(8) :: N, NRHS, LDB, INFO REAL(8), DIMENSION(:) :: A REAL(8), DIMENSION(:,:) :: B
#include <sunperf.h>
void dtptrs(char uplo, char transa, char diag, int n, int nrhs, double *a, double *b, int ldb, int *info);
void dtptrs_64(char uplo, char transa, char diag, long n, long nrhs, double *a, double *b, long ldb, long *info);
dtptrs solves a triangular system of the form
where A is a triangular matrix of order N stored in packed format, and B is an N-by-NRHS matrix. A check is made to verify that A is nonsingular.
= 'U': A is upper triangular;
= 'L': A is lower triangular.
= 'N': A * X = B (No transpose)
= 'T': A**T * X = B (Transpose)
= 'C': A**H * X = B (Conjugate transpose = Transpose)
= 'N': A is non-unit triangular;
= 'U': A is unit triangular.
A(i,j)
for 1 < =i < =j;
if UPLO = 'L', A(i + (j-1)*(2*n-j)/2) = A(i,j)
for j < =i < =n.
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
> 0: if INFO = i, the i-th diagonal element of A is zero, indicating that the matrix is singular and the solutions X have not been computed.