SRC/dlagtm.f(3)

NAME
SRC/dlagtm.f

SYNOPSIS

  Functions/Subroutines
subroutine dlagtm (trans, n, nrhs, alpha, dl, d, du, x, ldx, beta, b, ldb)
DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

Function/Subroutine Documentation

  subroutine dlagtm (character trans, integer n, integer nrhs, double precision alpha, double precision, dimension( * ) dl, double precision, dimension( * ) d, double precision, dimension( * ) du, double precision, dimension( ldx, * ) x, integer ldx, double precision beta, double precision, dimension( ldb, * ) b, integer ldb)

DLAGTM performs a matrix-matrix product of the form C = αAB+βC, where A is a tridiagonal matrix, B and C are rectangular matrices, and α and β are scalars, which may be 0, 1, or -1.

Purpose:

    !>
    !> DLAGTM performs a matrix-matrix product of the form
    !>
    !>    B := alpha * A * X + beta * B
    !>
    !> where A is a tridiagonal matrix of order N, B and X are N by NRHS
    !> matrices, and alpha and beta are real scalars, each of which may be
    !> 0., 1., or -1.
    !>

Parameters
    TRANS

    !>          TRANS is CHARACTER*1
    !>          Specifies the operation applied to A.
    !>          = 'N':  No transpose, B := alpha * A * X + beta * B
    !>          = 'T':  Transpose,    B := alpha * A'* X + beta * B
    !>          = 'C':  Conjugate transpose = Transpose
    !>

    N

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

    NRHS

    !>          NRHS is INTEGER
    !>          The number of right hand sides, i.e., the number of columns
    !>          of the matrices X and B.
    !>

    ALPHA

    !>          ALPHA is DOUBLE PRECISION
    !>          The scalar alpha.  ALPHA must be 0., 1., or -1.; otherwise,
    !>          it is assumed to be 0.
    !>

    DL

    !>          DL is DOUBLE PRECISION array, dimension (N-1)
    !>          The (n-1) sub-diagonal elements of T.
    !>

    D

    !>          D is DOUBLE PRECISION array, dimension (N)
    !>          The diagonal elements of T.
    !>

    DU

    !>          DU is DOUBLE PRECISION array, dimension (N-1)
    !>          The (n-1) super-diagonal elements of T.
    !>

    X

    !>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
    !>          The N by NRHS matrix X.
    !>

    LDX

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

    BETA

    !>          BETA is DOUBLE PRECISION
    !>          The scalar beta.  BETA must be 0., 1., or -1.; otherwise,
    !>          it is assumed to be 1.
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
    !>          On entry, the N by NRHS matrix B.
    !>          On exit, B is overwritten by the matrix expression
    !>          B := alpha * A * X + beta * B.
    !>

    LDB

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

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 143 of file dlagtm.f.

Author

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