SYNOPSIS
 SUBROUTINE DORG2R(
 M, N, K, A, LDA, TAU, WORK, INFO )
 INTEGER INFO, K, LDA, M, N
 DOUBLE PRECISION A( LDA, * ), TAU( * ), WORK( * )
PURPOSE
DORG2R generates an m by n real matrix Q with orthonormal columns, which is defined as the first n columns of a product of k elementary reflectors of order mQ = H(1) H(2) . . . H(k)
as returned by DGEQRF.
ARGUMENTS
 M (input) INTEGER
 The number of rows of the matrix Q. M >= 0.
 N (input) INTEGER
 The number of columns of the matrix Q. M >= N >= 0.
 K (input) INTEGER
 The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.
 A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
 On entry, the ith column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by DGEQRF in the first k columns of its array argument A. On exit, the mbyn matrix Q.
 LDA (input) INTEGER
 The first dimension of the array A. LDA >= max(1,M).
 TAU (input) DOUBLE PRECISION array, dimension (K)
 TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGEQRF.
 WORK (workspace) DOUBLE PRECISION array, dimension (N)
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument has an illegal value