DORGTR (3)  Linux Manuals
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.
NN is INTEGER The order of the matrix Q. N >= 0.
AA 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.
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).
TAUTAU is DOUBLE PRECISION array, dimension (N1) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DSYTRD.
WORKWORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORKLWORK 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.
INFOINFO 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
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