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## zgbtrs()

subroutine zgbtrs | ( | character | trans,
|  | integer | n,
|  | integer | kl,
|  | integer | ku,
|  | integer | nrhs,
|  | complex*16, dimension( ldab, * ) | ab,
|  | integer | ldab,
|  | integer, dimension( * ) | ipiv,
|  | complex*16, dimension( ldb, * ) | b,
|  | integer | ldb,
|  | integer | info )

ZGBTRS

Download ZGBTRS + dependencies [TGZ] [ZIP] [TXT]

Purpose:

      !>
      !> ZGBTRS solves a system of linear equations
      !>    A * X = B,  A**T * X = B,  or  A**H * X = B
      !> with a general band matrix A using the LU factorization computed
      !> by ZGBTRF.
      !>

Parameters

  [in]

  TRANS

      !>          TRANS is CHARACTER*1
      !>          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)
      !>

  [in]

  N

      !>          N is INTEGER
      !>          The order of the matrix A.  N >= 0.
      !>

  [in]

  KL

      !>          KL is INTEGER
      !>          The number of subdiagonals within the band of A.  KL >= 0.
      !>

  [in]

  KU

      !>          KU is INTEGER
      !>          The number of superdiagonals within the band of A.  KU >= 0.
      !>

  [in]

  NRHS

      !>          NRHS is INTEGER
      !>          The number of right hand sides, i.e., the number of columns
      !>          of the matrix B.  NRHS >= 0.
      !>

  [in]

  AB

      !>          AB is COMPLEX*16 array, dimension (LDAB,N)
      !>          Details of the LU factorization of the band matrix A, as
      !>          computed by ZGBTRF.  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.
      !>

  [in]

  LDAB

      !>          LDAB is INTEGER
      !>          The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.
      !>

  [in]

  IPIV

      !>          IPIV is INTEGER array, dimension (N)
      !>          The pivot indices; for 1 <= i <= N, row i of the matrix was
      !>          interchanged with row IPIV(i).
      !>

  [in,out]

  B

      !>          B is COMPLEX*16 array, dimension (LDB,NRHS)
      !>          On entry, the right hand side matrix B.
      !>          On exit, the solution matrix X.
      !>

  [in]

  LDB

      !>          LDB is INTEGER
      !>          The leading dimension of the array B.  LDB >= max(1,N).
      !>

  [out]

  INFO

      !>          INFO is INTEGER
      !>          = 0:  successful exit
      !>          < 0:  if INFO = -i, the i-th argument had an illegal value
      !>

Author
  Univ. of Tennessee
  Univ. of California Berkeley
  Univ. of Colorado Denver
  NAG Ltd.