dlagtm.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

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-vector 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.

Date:

December 2016

Definition at line 147 of file dlagtm.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
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)
Author
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