
dorgtr.f(3) LAPACK dorgtr.f(3)
NAME
dorgtr.f 
SYNOPSIS
Functions/Subroutines
subroutine dorgtr (UPLO, N, A, LDA, TAU, WORK, LWORK, INFO)
DORGTR
Function/Subroutine Documentation
subroutine dorgtr (characterUPLO, integerN, double precision, dimension( lda, * )A,
integerLDA, double precision, dimension( * )TAU, double precision, dimension( * )WORK,
integerLWORK, integerINFO)
DORGTR
Purpose:
DORGTR generates a real orthogonal matrix Q which is defined as the
product of n1 elementary reflectors of order N, as returned by
DSYTRD:
if UPLO = 'U', Q = H(n1) . . . H(2) H(1),
if UPLO = 'L', Q = H(1) H(2) . . . H(n1).
Parameters:
UPLO
UPLO is CHARACTER*1
= 'U': Upper triangle of A contains elementary reflectors
from DSYTRD;
= 'L': Lower triangle of A contains elementary reflectors
from DSYTRD.
N
N is INTEGER
The order of the matrix Q. N >= 0.
A
A is DOUBLE PRECISION array, dimension (LDA,N)
On entry, the vectors which define the elementary reflectors,
as returned by DSYTRD.
On exit, the NbyN orthogonal matrix Q.
LDA
LDA is INTEGER
The leading dimension of the array A. LDA >= max(1,N).
TAU
TAU is DOUBLE PRECISION array, dimension (N1)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by DSYTRD.
WORK
WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK
LWORK is INTEGER
The dimension of the array WORK. LWORK >= max(1,N1).
For optimum performance LWORK >= (N1)*NB, where NB is
the optimal blocksize.
If LWORK = 1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
INFO
INFO is INTEGER
= 0: successful exit
< 0: if INFO = i, the ith 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 124 of file dorgtr.f.
Author
Generated automatically by Doxygen for LAPACK from the source code.
Version 3.4.2 Tue Sep 25 2012 dorgtr.f(3) 
