ctrtrs(3P) Sun Performance Library ctrtrs(3P)NAMEctrtrs - solve a triangular system of the form A * X = B, A**T * X =
B, or A**H * X = B,
SYNOPSIS
SUBROUTINE CTRTRS(UPLO, TRANSA, DIAG, N, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO, TRANSA, DIAG
COMPLEX A(LDA,*), B(LDB,*)
INTEGER N, NRHS, LDA, LDB, INFO
SUBROUTINE CTRTRS_64(UPLO, TRANSA, DIAG, N, NRHS, A, LDA, B, LDB,
INFO)
CHARACTER * 1 UPLO, TRANSA, DIAG
COMPLEX A(LDA,*), B(LDB,*)
INTEGER*8 N, NRHS, LDA, LDB, INFO
F95 INTERFACE
SUBROUTINE TRTRS(UPLO, [TRANSA], DIAG, [N], [NRHS], A, [LDA], B, [LDB],
[INFO])
CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
COMPLEX, DIMENSION(:,:) :: A, B
INTEGER :: N, NRHS, LDA, LDB, INFO
SUBROUTINE TRTRS_64(UPLO, [TRANSA], DIAG, [N], [NRHS], A, [LDA], B,
[LDB], [INFO])
CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
COMPLEX, DIMENSION(:,:) :: A, B
INTEGER(8) :: N, NRHS, LDA, LDB, INFO
C INTERFACE
#include <sunperf.h>
void ctrtrs(char uplo, char transa, char diag, int n, int nrhs, complex
*a, int lda, complex *b, int ldb, int *info);
void ctrtrs_64(char uplo, char transa, char diag, long n, long nrhs,
complex *a, long lda, complex *b, long ldb, long *info);
PURPOSEctrtrs solves a triangular system of the form
A * X = B, A**T * X = B, or A**H * X = B
where A is a triangular matrix of order N, and B is an N-by-NRHS
matrix. A check is made to verify that A is nonsingular.
ARGUMENTS
UPLO (input)
= 'U': A is upper triangular;
= 'L': A is lower triangular.
TRANSA (input)
Specifies the form of the system of equations:
= 'N': A * X = B (No transpose)
= 'T': A**T * X = B (Transpose)
= 'C': A**H * X = B (Conjugate transpose)
TRANSA is defaulted to 'N' for F95 INTERFACE.
DIAG (input)
= 'N': A is non-unit triangular;
= 'U': A is unit triangular.
N (input) The order of the matrix A. N >= 0.
NRHS (input)
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.
A (input) The triangular matrix A. If UPLO = 'U', the leading N-by-N
upper triangular part of the array A contains the upper tri‐
angular matrix, and the strictly lower triangular part of A
is not referenced. If UPLO = 'L', the leading N-by-N lower
triangular part of the array A contains the lower triangular
matrix, and the strictly upper triangular part of A is not
referenced. If DIAG = 'U', the diagonal elements of A are
also not referenced and are assumed to be 1.
LDA (input)
The leading dimension of the array A. LDA >= max(1,N).
B (input/output)
On entry, the right hand side matrix B. On exit, if INFO =
0, the solution matrix X.
LDB (input)
The leading dimension of the array B. LDB >= max(1,N).
INFO (output)
= 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.
6 Mar 2009 ctrtrs(3P)
