LAPACK  3.5.0
LAPACK: Linear Algebra PACKage
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dlaptm.f File Reference

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Functions/Subroutines

subroutine dlaptm (N, NRHS, ALPHA, D, E, X, LDX, BETA, B, LDB)
 DLAPTM More...
 

Function/Subroutine Documentation

subroutine dlaptm ( integer  N,
integer  NRHS,
double precision  ALPHA,
double precision, dimension( * )  D,
double precision, dimension( * )  E,
double precision, dimension( ldx, * )  X,
integer  LDX,
double precision  BETA,
double precision, dimension( ldb, * )  B,
integer  LDB 
)

DLAPTM

Purpose:
 DLAPTM multiplies an N by NRHS matrix X by a symmetric tridiagonal
 matrix A and stores the result in a matrix B.  The operation has the
 form

    B := alpha * A * X + beta * B

 where alpha may be either 1. or -1. and beta may be 0., 1., or -1.
Parameters
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in]NRHS
          NRHS is INTEGER
          The number of right hand sides, i.e., the number of columns
          of the matrices X and B.
[in]ALPHA
          ALPHA is DOUBLE PRECISION
          The scalar alpha.  ALPHA must be 1. or -1.; otherwise,
          it is assumed to be 0.
[in]D
          D is DOUBLE PRECISION array, dimension (N)
          The n diagonal elements of the tridiagonal matrix A.
[in]E
          E is DOUBLE PRECISION array, dimension (N-1)
          The (n-1) subdiagonal or superdiagonal elements of A.
[in]X
          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
          The N by NRHS matrix X.
[in]LDX
          LDX is INTEGER
          The leading dimension of the array X.  LDX >= max(N,1).
[in]BETA
          BETA is DOUBLE PRECISION
          The scalar beta.  BETA must be 0., 1., or -1.; otherwise,
          it is assumed to be 1.
[in,out]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.
[in]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
November 2011

Definition at line 117 of file dlaptm.f.

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