1CUNGR2(1) LAPACK routine (version 3.1) CUNGR2(1)
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6 CUNGR2 - an m by n complex matrix Q with orthonormal rows,
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9 SUBROUTINE CUNGR2( M, N, K, A, LDA, TAU, WORK, INFO )
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11 INTEGER INFO, K, LDA, M, N
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13 COMPLEX A( LDA, * ), TAU( * ), WORK( * )
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16 CUNGR2 generates an m by n complex matrix Q with orthonormal rows,
17 which is defined as the last m rows of a product of k elementary
18 reflectors of order n
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20 Q = H(1)' H(2)' . . . H(k)'
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22 as returned by CGERQF.
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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. N >= M.
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32 K (input) INTEGER
33 The number of elementary reflectors whose product defines the
34 matrix Q. M >= K >= 0.
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36 A (input/output) COMPLEX array, dimension (LDA,N)
37 On entry, the (m-k+i)-th row must contain the vector which
38 defines the elementary reflector H(i), for i = 1,2,...,k, as
39 returned by CGERQF in the last k rows of its array argument A.
40 On 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) COMPLEX array, dimension (K)
46 TAU(i) must contain the scalar factor of the elementary reflecā
47 tor H(i), as returned by CGERQF.
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49 WORK (workspace) COMPLEX array, dimension (M)
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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 CUNGR2(1)