Contents
ctbtrs - solve a triangular system of the form A * X = B,
A**T * X = B, or A**H * X = B,
SUBROUTINE CTBTRS(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B, LDB,
INFO)
CHARACTER * 1 UPLO, TRANSA, DIAG
COMPLEX A(LDA,*), B(LDB,*)
INTEGER N, KD, NRHS, LDA, LDB, INFO
SUBROUTINE CTBTRS_64(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
LDB, INFO)
CHARACTER * 1 UPLO, TRANSA, DIAG
COMPLEX A(LDA,*), B(LDB,*)
INTEGER*8 N, KD, NRHS, LDA, LDB, INFO
F95 INTERFACE
SUBROUTINE TBTRS(UPLO, [TRANSA], DIAG, [N], KD, [NRHS], A, [LDA], B,
[LDB], [INFO])
CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
COMPLEX, DIMENSION(:,:) :: A, B
INTEGER :: N, KD, NRHS, LDA, LDB, INFO
SUBROUTINE TBTRS_64(UPLO, [TRANSA], DIAG, [N], KD, [NRHS], A, [LDA],
B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
COMPLEX, DIMENSION(:,:) :: A, B
INTEGER(8) :: N, KD, NRHS, LDA, LDB, INFO
C INTERFACE
#include <sunperf.h>
void ctbtrs(char uplo, char transa, char diag, int n, int
kd, int nrhs, complex *a, int lda, complex *b, int
ldb, int *info);
void ctbtrs_64(char uplo, char transa, char diag, long n,
long kd, long nrhs, complex *a, long lda, complex
*b, long ldb, long *info);
ctbtrs solves a triangular system of the form
A * X = B, A**T * X = B, or A**H * X = B
where A is a triangular band matrix of order N, and B is an
N-by-NRHS matrix. A check is made to verify that A is non-
singular.
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)
DIAG (input)
= 'N': A is non-unit triangular;
= 'U': A is unit triangular.
N (input) The order of the matrix A. N >= 0.
KD (input)
The number of superdiagonals or subdiagonals of
the triangular band matrix A. KD >= 0.
NRHS (input)
The number of right hand sides, i.e., the number
of columns of the matrix B. NRHS >= 0.
A (input) The upper or lower triangular band matrix A,
stored in the first kd+1 rows of A. The j-th
column of A is stored in the j-th column of the
array A as follows: if UPLO = 'U', A(kd+1+i-j,j)
= A(i,j) for max(1,j-kd)<=i<=j; if UPLO = 'L',
A(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). If
DIAG = 'U', the diagonal elements of A are not
referenced and are assumed to be 1.
LDA (input)
The leading dimension of the array A. LDA >=
KD+1.
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 ille-
gal 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.