SRC/zpttrs.f(3)

NAME
SRC/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)

ZPTTRS

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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