zpttrs.f(3)

NAME
zpttrs.f

SYNOPSIS

  Functions/Subroutines
subroutine zpttrs (UPLO, N, NRHS, D, E, B, LDB, INFO)
ZPTTRS

Function/Subroutine Documentation

  subroutine zpttrs (character UPLO, integer N, integer NRHS, double precision, dimension( * ) D, complex*16, dimension( * ) E, complex*16, dimension( ldb, * ) B, integer LDB, integer INFO)

Purpose:

     ZPTTRS solves a tridiagonal system of the form
        A * X = B
     using the factorization A = U**H *D* U or A = L*D*L**H computed by ZPTTRF.
     D is a diagonal matrix specified in the vector D, U (or L) is a unit
     bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
     the vector E, and X and B are N by NRHS matrices.

Parameters
    UPLO

              UPLO is CHARACTER*1
              Specifies the form of the factorization and whether the
              vector E is the superdiagonal of the upper bidiagonal factor
              U or the subdiagonal of the lower bidiagonal factor L.
              = 'U':  A = U**H *D*U, E is the superdiagonal of U
              = 'L':  A = L*D*L**H, E is the subdiagonal of L

    N

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

    NRHS

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

    D

              D is DOUBLE PRECISION array, dimension (N)
              The n diagonal elements of the diagonal matrix D from the
              factorization A = U**H *D*U or A = L*D*L**H.

    E

              E is COMPLEX*16 array, dimension (N-1)
              If UPLO = 'U', the (n-1) superdiagonal elements of the unit
              bidiagonal factor U from the factorization A = U**H*D*U.
              If UPLO = 'L', the (n-1) subdiagonal elements of the unit
              bidiagonal factor L from the factorization A = L*D*L**H.

    B

              B is COMPLEX*16 array, dimension (LDB,NRHS)
              On entry, the right hand side vectors B for the system of
              linear equations.
              On exit, the solution vectors, X.

    LDB

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

    INFO

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

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 120 of file zpttrs.f.

Author

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