dopgtr.f man page

dopgtr.f —

Synopsis

Functions/Subroutines

subroutine dopgtr (UPLO, N, AP, TAU, Q, LDQ, WORK, INFO)
DOPGTR

Function/Subroutine Documentation

subroutine dopgtr (characterUPLO, integerN, double precision, dimension( * )AP, double precision, dimension( * )TAU, double precision, dimension( ldq, * )Q, integerLDQ, double precision, dimension( * )WORK, integerINFO)

DOPGTR

Purpose:

DOPGTR generates a real orthogonal matrix Q which is defined as the
product of n-1 elementary reflectors H(i) of order n, as returned by
DSPTRD using packed storage:

if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),

if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).

Parameters:

UPLO

UPLO is CHARACTER*1
= 'U': Upper triangular packed storage used in previous
       call to DSPTRD;
= 'L': Lower triangular packed storage used in previous
       call to DSPTRD.

N

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

AP

AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
The vectors which define the elementary reflectors, as
returned by DSPTRD.

TAU

TAU is DOUBLE PRECISION array, dimension (N-1)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by DSPTRD.

Q

Q is DOUBLE PRECISION array, dimension (LDQ,N)
The N-by-N orthogonal matrix Q.

LDQ

LDQ is INTEGER
The leading dimension of the array Q. LDQ >= max(1,N).

WORK

WORK is DOUBLE PRECISION array, dimension (N-1)

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Definition at line 115 of file dopgtr.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

dopgtr(3) is an alias of dopgtr.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK