1DORG2R(1)                LAPACK routine (version 3.1)                DORG2R(1)
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NAME

6       DORG2R - an m by n real matrix Q with orthonormal columns,
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SYNOPSIS

9       SUBROUTINE DORG2R( M, N, K, A, LDA, TAU, WORK, INFO )
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11           INTEGER        INFO, K, LDA, M, N
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13           DOUBLE         PRECISION A( LDA, * ), TAU( * ), WORK( * )
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PURPOSE

16       DORG2R  generates  an  m  by  n real matrix Q with orthonormal columns,
17       which is defined as the first n columns of a product  of  k  elementary
18       reflectors of order m
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20             Q  =  H(1) H(2) . . . H(k)
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22       as returned by DGEQRF.
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ARGUMENTS

26       M       (input) INTEGER
27               The number of rows of the matrix Q. M >= 0.
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29       N       (input) INTEGER
30               The number of columns of the matrix Q. M >= N >= 0.
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32       K       (input) INTEGER
33               The  number  of elementary reflectors whose product defines the
34               matrix Q. N >= K >= 0.
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36       A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
37               On entry, the i-th column must contain the vector which defines
38               the  elementary  reflector H(i), for i = 1,2,...,k, as returned
39               by DGEQRF in the first k columns of its array argument  A.   On
40               exit, the m-by-n matrix Q.
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42       LDA     (input) INTEGER
43               The first dimension of the array A. LDA >= max(1,M).
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45       TAU     (input) DOUBLE PRECISION array, dimension (K)
46               TAU(i) must contain the scalar factor of the elementary reflec‐
47               tor H(i), as returned by DGEQRF.
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49       WORK    (workspace) DOUBLE PRECISION array, dimension (N)
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51       INFO    (output) INTEGER
52               = 0: successful exit
53               < 0: if INFO = -i, the i-th argument has an illegal value
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57 LAPACK routine (version 3.1)    November 2006                       DORG2R(1)