1CUNG2R(1) LAPACK routine (version 3.1) CUNG2R(1)
2
3
4
6 CUNG2R - an m by n complex matrix Q with orthonormal columns,
7
9 SUBROUTINE CUNG2R( M, N, K, A, LDA, TAU, WORK, INFO )
10
11 INTEGER INFO, K, LDA, M, N
12
13 COMPLEX A( LDA, * ), TAU( * ), WORK( * )
14
16 CUNG2R generates an m by n complex 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
19
20 Q = H(1) H(2) . . . H(k)
21
22 as returned by CGEQRF.
23
24
26 M (input) INTEGER
27 The number of rows of the matrix Q. M >= 0.
28
29 N (input) INTEGER
30 The number of columns of the matrix Q. M >= N >= 0.
31
32 K (input) INTEGER
33 The number of elementary reflectors whose product defines the
34 matrix Q. N >= K >= 0.
35
36 A (input/output) COMPLEX 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 CGEQRF in the first k columns of its array argument A. On
40 exit, the m by n matrix Q.
41
42 LDA (input) INTEGER
43 The first dimension of the array A. LDA >= max(1,M).
44
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 CGEQRF.
48
49 WORK (workspace) COMPLEX array, dimension (N)
50
51 INFO (output) INTEGER
52 = 0: successful exit
53 < 0: if INFO = -i, the i-th argument has an illegal value
54
55
56
57 LAPACK routine (version 3.1) November 2006 CUNG2R(1)