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

6       CUNGLQ - an M-by-N complex matrix Q with orthonormal rows,
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SYNOPSIS

9       SUBROUTINE CUNGLQ( M, N, K, A, LDA, TAU, WORK, LWORK, INFO )
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11           INTEGER        INFO, K, LDA, LWORK, M, N
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13           COMPLEX        A( LDA, * ), TAU( * ), WORK( * )
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PURPOSE

16       CUNGLQ  generates  an  M-by-N  complex  matrix Q with orthonormal rows,
17       which is defined as the first M rows  of  a  product  of  K  elementary
18       reflectors of order N
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20             Q  =  H(k)' . . . H(2)' H(1)'
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22       as returned by CGELQF.
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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. 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 i-th row must contain the  vector  which  defines
38               the  elementary  reflector H(i), for i = 1,2,...,k, as returned
39               by CGELQF in the first k rows 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) COMPLEX array, dimension (K)
46               TAU(i) must contain the scalar factor of the elementary reflec‐
47               tor H(i), as returned by CGELQF.
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49       WORK    (workspace/output) COMPLEX array, dimension (MAX(1,LWORK))
50               On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
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52       LWORK   (input) INTEGER
53               The dimension of the array WORK. LWORK >= max(1,M).  For  opti‐
54               mum  performance  LWORK >= M*NB, where NB is the optimal block‐
55               size.
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57               If LWORK = -1, then a workspace query is assumed;  the  routine
58               only  calculates  the  optimal  size of the WORK array, returns
59               this value as the first entry of the WORK array, and  no  error
60               message related to LWORK is issued by XERBLA.
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62       INFO    (output) INTEGER
63               = 0:  successful exit;
64               < 0:  if INFO = -i, the i-th argument has an illegal value
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68 LAPACK routine (version 3.1)    November 2006                       CUNGLQ(1)