dtbtrs (3p)

Name

dtbtrs - solve a triangular system of the form A*X = B or A**T*X = B, where A is a triangular band matrix of order N, and B is an N-by-NRHS matrix

Synopsis

SUBROUTINE DTBTRS(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B, LDB,
INFO)

CHARACTER*1 UPLO, TRANSA, DIAG
INTEGER N, KD, NRHS, LDA, LDB, INFO
DOUBLE PRECISION A(LDA,*), B(LDB,*)

SUBROUTINE DTBTRS_64(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
LDB, INFO)

CHARACTER*1 UPLO, TRANSA, DIAG
INTEGER*8 N, KD, NRHS, LDA, LDB, INFO
DOUBLE PRECISION A(LDA,*), B(LDB,*)




F95 INTERFACE
SUBROUTINE TBTRS(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
LDB, INFO)

CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
INTEGER :: N, KD, NRHS, LDA, LDB, INFO
REAL(8), DIMENSION(:,:) :: A, B

SUBROUTINE TBTRS_64(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
LDB, INFO)

CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
INTEGER(8) :: N, KD, NRHS, LDA, LDB, INFO
REAL(8), DIMENSION(:,:) :: A, B




C INTERFACE
#include <sunperf.h>

void dtbtrs(char uplo, char transa, char diag, int n, int kd, int nrhs,
double *a, int lda, double *b, int ldb, int *info);

void dtbtrs_64(char uplo, char transa, char diag, long n, long kd, long
nrhs, double *a, long lda, double *b, long ldb, long *info);

Description

Oracle Solaris Studio Performance Library                           dtbtrs(3P)



NAME
       dtbtrs  -  solve a triangular system of the form A*X = B or A**T*X = B,
       where A is a triangular band matrix of order N, and B is  an  N-by-NRHS
       matrix


SYNOPSIS
       SUBROUTINE DTBTRS(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B, LDB,
             INFO)

       CHARACTER*1 UPLO, TRANSA, DIAG
       INTEGER N, KD, NRHS, LDA, LDB, INFO
       DOUBLE PRECISION A(LDA,*), B(LDB,*)

       SUBROUTINE DTBTRS_64(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
             LDB, INFO)

       CHARACTER*1 UPLO, TRANSA, DIAG
       INTEGER*8 N, KD, NRHS, LDA, LDB, INFO
       DOUBLE PRECISION A(LDA,*), B(LDB,*)




   F95 INTERFACE
       SUBROUTINE TBTRS(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
              LDB, INFO)

       CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
       INTEGER :: N, KD, NRHS, LDA, LDB, INFO
       REAL(8), DIMENSION(:,:) :: A, B

       SUBROUTINE TBTRS_64(UPLO, TRANSA, DIAG, N, KD, NRHS, A, LDA, B,
              LDB, INFO)

       CHARACTER(LEN=1) :: UPLO, TRANSA, DIAG
       INTEGER(8) :: N, KD, NRHS, LDA, LDB, INFO
       REAL(8), DIMENSION(:,:) :: A, B




   C INTERFACE
       #include <sunperf.h>

       void dtbtrs(char uplo, char transa, char diag, int n, int kd, int nrhs,
                 double *a, int lda, double *b, int ldb, int *info);

       void dtbtrs_64(char uplo, char transa, char diag, long n, long kd, long
                 nrhs, double *a, long lda, double *b, long ldb, long *info);



PURPOSE
       dtbtrs solves a triangular system of the form

       A * X = B or A**T * 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 nonsingular.


ARGUMENTS
       UPLO (input)
                 = 'U':  A is upper triangular;
                 = 'L':  A is lower triangular.


       TRANSA (input)
                 Specifies the form the system of equations:
                 = 'N':  A * X = B  (No transpose)
                 = 'T':  A**T * X = B  (Transpose)
                 = 'C':  A**H * X = B  (Conjugate transpose = 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  triangu-
                 lar 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 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.




                                  7 Nov 2015                        dtbtrs(3P)