• NAME
• SYNOPSIS
• F95 INTERFACE
• C INTERFACE
• PURPOSE
• ARGUMENTS

NAME

dgbtrs - solve a system of linear equations A * X = B or A' * X = B with a general band matrix A using the LU factorization computed by SGBTRF

SYNOPSIS

  SUBROUTINE DGBTRS( TRANSA, N, NSUB, NSUPER, NRHS, A, LDA, IPIVOT, B, 
 *      LDB, INFO)
  CHARACTER * 1 TRANSA
  INTEGER N, NSUB, NSUPER, NRHS, LDA, LDB, INFO
  INTEGER IPIVOT(*)
  DOUBLE PRECISION A(LDA,*), B(LDB,*)

  SUBROUTINE DGBTRS_64( TRANSA, N, NSUB, NSUPER, NRHS, A, LDA, IPIVOT, 
 *      B, LDB, INFO)
  CHARACTER * 1 TRANSA
  INTEGER*8 N, NSUB, NSUPER, NRHS, LDA, LDB, INFO
  INTEGER*8 IPIVOT(*)
  DOUBLE PRECISION A(LDA,*), B(LDB,*)

F95 INTERFACE

  SUBROUTINE GBTRS( [TRANSA], [N], NSUB, NSUPER, [NRHS], A, [LDA], 
 *       IPIVOT, B, [LDB], [INFO])
  CHARACTER(LEN=1) :: TRANSA
  INTEGER :: N, NSUB, NSUPER, NRHS, LDA, LDB, INFO
  INTEGER, DIMENSION(:) :: IPIVOT
  REAL(8), DIMENSION(:,:) :: A, B

  SUBROUTINE GBTRS_64( [TRANSA], [N], NSUB, NSUPER, [NRHS], A, [LDA], 
 *       IPIVOT, B, [LDB], [INFO])
  CHARACTER(LEN=1) :: TRANSA
  INTEGER(8) :: N, NSUB, NSUPER, NRHS, LDA, LDB, INFO
  INTEGER(8), DIMENSION(:) :: IPIVOT
  REAL(8), DIMENSION(:,:) :: A, B

C INTERFACE

#include <sunperf.h>

void dgbtrs(char transa, int n, int nsub, int nsuper, int nrhs, double *a, int lda, int *ipivot, double *b, int ldb, int *info);

void dgbtrs_64(char transa, long n, long nsub, long nsuper, long nrhs, double *a, long lda, long *ipivot, double *b, long ldb, long *info);

PURPOSE

dgbtrs solves a system of linear equations A * X = B or A' * X = B with a general band matrix A using the LU factorization computed by SGBTRF.

ARGUMENTS

• TRANSA (input)
  Specifies the form of the system of equations. = 'N': A * X = B (No transpose)

   = 'T':  A'* X  = B  (Transpose)

   = 'C':  A'* X  = B  (Conjugate transpose  = Transpose)

• N (input)
  The order of the matrix A. N > = 0.

• NSUB (input)
  The number of subdiagonals within the band of A. NSUB > = 0.

• NSUPER (input)
  The number of superdiagonals within the band of A. NSUPER > = 0.

• NRHS (input)
  The number of right hand sides, i.e., the number of columns of the matrix B. NRHS > = 0.

• A (input)
  Details of the LU factorization of the band matrix A, as computed by SGBTRF. U is stored as an upper triangular band matrix with NSUB+NSUPER superdiagonals in rows 1 to NSUB+NSUPER+1, and the multipliers used during the factorization are stored in rows NSUB+NSUPER+2 to 2*NSUB+NSUPER+1.

• LDA (input)
  The leading dimension of the array A. LDA > = 2*NSUB+NSUPER+1.

• IPIVOT (input)
  The pivot indices; for 1 < = i < = N, row i of the matrix was interchanged with row IPIVOT(i).

• B (input/output)
  On entry, the right hand side matrix B. On exit, 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