dgbtrs (l)  Linux Manuals
dgbtrs: solves a system of linear equations A * X = B or Aaq * X = B with a general band matrix A using the LU factorization computed by DGBTRF
NAME
DGBTRS  solves a system of linear equations A * X = B or Aaq * X = B with a general band matrix A using the LU factorization computed by DGBTRFSYNOPSIS
 SUBROUTINE DGBTRS(
 TRANS, N, KL, KU, NRHS, AB, LDAB, IPIV, B, LDB, INFO )
 CHARACTER TRANS
 INTEGER INFO, KL, KU, LDAB, LDB, N, NRHS
 INTEGER IPIV( * )
 DOUBLE PRECISION AB( LDAB, * ), B( LDB, * )
PURPOSE
DGBTRS solves a system of linear equationsA
ARGUMENTS
 TRANS (input) CHARACTER*1

Specifies the form of the system of equations.
= aqNaq: A * X = B (No transpose)
= aqTaq: Aaq* X = B (Transpose)
= aqCaq: Aaq* X = B (Conjugate transpose = Transpose)  N (input) INTEGER
 The order of the matrix A. N >= 0.
 KL (input) INTEGER
 The number of subdiagonals within the band of A. KL >= 0.
 KU (input) INTEGER
 The number of superdiagonals within the band of A. KU >= 0.
 NRHS (input) INTEGER
 The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
 AB (input) DOUBLE PRECISION array, dimension (LDAB,N)
 Details of the LU factorization of the band matrix A, as computed by DGBTRF. U is stored as an upper triangular band matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and the multipliers used during the factorization are stored in rows KL+KU+2 to 2*KL+KU+1.
 LDAB (input) INTEGER
 The leading dimension of the array AB. LDAB >= 2*KL+KU+1.
 IPIV (input) INTEGER array, dimension (N)
 The pivot indices; for 1 <= i <= N, row i of the matrix was interchanged with row IPIV(i).
 B (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
 On entry, the right hand side matrix B. On exit, the solution matrix X.
 LDB (input) INTEGER
 The leading dimension of the array B. LDB >= max(1,N).
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value