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clagtm.f(3) LAPACK clagtm.f(3)

NAME

clagtm.f -

SYNOPSIS

Functions/Subroutines


subroutine clagtm (TRANS, N, NRHS, ALPHA, DL, D, DU, X, LDX, BETA, B, LDB)
 
CLAGTM 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 clagtm (characterTRANS, integerN, integerNRHS, realALPHA, complex, dimension( * )DL, complex, dimension( * )D, complex, dimension( * )DU, complex, dimension( ldx, * )X, integerLDX, realBETA, complex, dimension( ldb, * )B, integerLDB)

CLAGTM 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:
 CLAGTM 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**T * X + beta * B
          = 'C':  Conjugate transpose, B := alpha * A**H * X + beta * B
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 REAL
          The scalar alpha.  ALPHA must be 0., 1., or -1.; otherwise,
          it is assumed to be 0.
DL
          DL is COMPLEX array, dimension (N-1)
          The (n-1) sub-diagonal elements of T.
D
          D is COMPLEX array, dimension (N)
          The diagonal elements of T.
DU
          DU is COMPLEX array, dimension (N-1)
          The (n-1) super-diagonal elements of T.
X
          X is COMPLEX 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 REAL
          The scalar beta.  BETA must be 0., 1., or -1.; otherwise,
          it is assumed to be 1.
B
          B is COMPLEX 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:
September 2012
Definition at line 145 of file clagtm.f.

Author

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