SRC/spttrs.f(3)

NAME
SRC/spttrs.f

SYNOPSIS

  Functions/Subroutines
subroutine spttrs (n, nrhs, d, e, b, ldb, info)
SPTTRS

Function/Subroutine Documentation

  subroutine spttrs (integer n, integer nrhs, real, dimension( * ) d, real, dimension( * ) e, real, dimension( ldb, * ) b, integer ldb, integer info)

SPTTRS

Purpose:

    !>
    !> SPTTRS solves a tridiagonal system of the form
    !>    A * X = B
    !> using the L*D*L**T factorization of A computed by SPTTRF.  D is a
    !> diagonal matrix specified in the vector D, L is a unit bidiagonal
    !> matrix whose subdiagonal is specified in the vector E, and X and B
    !> are N by NRHS matrices.
    !>

Parameters
    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 REAL array, dimension (N)
    !>          The n diagonal elements of the diagonal matrix D from the
    !>          L*D*L**T factorization of A.
    !>

    E

    !>          E is REAL array, dimension (N-1)
    !>          The (n-1) subdiagonal elements of the unit bidiagonal factor
    !>          L from the L*D*L**T factorization of A.  E can also be regarded
    !>          as the superdiagonal of the unit bidiagonal factor U from the
    !>          factorization A = U**T*D*U.
    !>

    B

    !>          B is REAL 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 108 of file spttrs.f.

Author

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