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## zptsv()

subroutine zptsv | ( | integer | n,
|  | integer | nrhs,
|  | double precision, dimension( * ) | d,
|  | complex*16, dimension( * ) | e,
|  | complex*16, dimension( ldb, * ) | b,
|  | integer | ldb,
|  | integer | info )

ZPTSV computes the solution to system of linear equations A * X = B for PT matrices

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

Purpose:

      !>
      !> ZPTSV computes the solution to a complex system of linear equations
      !> A*X = B, where A is an N-by-N Hermitian positive definite tridiagonal
      !> matrix, and X and B are N-by-NRHS matrices.
      !>
      !> A is factored as A = L*D*L**H, and the factored form of A is then
      !> used to solve the system of equations.
      !>

Parameters

  [in]

  N

      !>          N is INTEGER
      !>          The order of the matrix A.  N >= 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,out]

  D

      !>          D is DOUBLE PRECISION array, dimension (N)
      !>          On entry, the n diagonal elements of the tridiagonal matrix
      !>          A.  On exit, the n diagonal elements of the diagonal matrix
      !>          D from the factorization A = L*D*L**H.
      !>

  [in,out]

  E

      !>          E is COMPLEX*16 array, dimension (N-1)
      !>          On entry, the (n-1) subdiagonal elements of the tridiagonal
      !>          matrix A.  On exit, the (n-1) subdiagonal elements of the
      !>          unit bidiagonal factor L from the L*D*L**H factorization of
      !>          A.  E can also be regarded as the superdiagonal of the unit
      !>          bidiagonal factor U from the U**H*D*U factorization of A.
      !>

  [in,out]

  B

      !>          B is COMPLEX*16 array, dimension (LDB,NRHS)
      !>          On entry, the N-by-NRHS right hand side matrix B.
      !>          On exit, if INFO = 0, the N-by-NRHS 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
      !>          > 0:  if INFO = i, the leading principal minor of order i
      !>                is not positive, and the solution has not been
      !>                computed.  The factorization has not been completed
      !>                unless i = N.
      !>

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