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

6       CUPGTR  - a complex unitary matrix Q which is defined as the product of
7       n-1 elementary reflectors H(i) of order n, as returned by CHPTRD  using
8       packed storage
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SYNOPSIS

11       SUBROUTINE CUPGTR( UPLO, N, AP, TAU, Q, LDQ, WORK, INFO )
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13           CHARACTER      UPLO
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15           INTEGER        INFO, LDQ, N
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17           COMPLEX        AP( * ), Q( LDQ, * ), TAU( * ), WORK( * )
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PURPOSE

20       CUPGTR  generates  a  complex  unitary matrix Q which is defined as the
21       product of n-1 elementary reflectors H(i) of order n,  as  returned  by
22       CHPTRD using packed storage:
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24       if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),
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26       if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).
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ARGUMENTS

30       UPLO    (input) CHARACTER*1
31               = 'U': Upper triangular packed storage used in previous call to
32               CHPTRD; = 'L': Lower triangular packed storage used in previous
33               call to CHPTRD.
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35       N       (input) INTEGER
36               The order of the matrix Q. N >= 0.
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38       AP      (input) COMPLEX array, dimension (N*(N+1)/2)
39               The vectors which define the elementary reflectors, as returned
40               by CHPTRD.
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42       TAU     (input) COMPLEX array, dimension (N-1)
43               TAU(i) must contain the scalar factor of the elementary reflec‐
44               tor H(i), as returned by CHPTRD.
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46       Q       (output) COMPLEX array, dimension (LDQ,N)
47               The N-by-N unitary matrix Q.
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49       LDQ     (input) INTEGER
50               The leading dimension of the array Q. LDQ >= max(1,N).
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52       WORK    (workspace) COMPLEX array, dimension (N-1)
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54       INFO    (output) INTEGER
55               = 0:  successful exit
56               < 0:  if INFO = -i, the i-th argument had an illegal value
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60 LAPACK routine (version 3.1)    November 2006                       CUPGTR(1)
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