
ZUPGTR(l) ) ZUPGTR(l)
NAME
ZUPGTR  generate a complex unitary matrix Q which is defined as the product of n1 ele
mentary reflectors H(i) of order n, as returned by ZHPTRD using packed storage
SYNOPSIS
SUBROUTINE ZUPGTR( UPLO, N, AP, TAU, Q, LDQ, WORK, INFO )
CHARACTER UPLO
INTEGER INFO, LDQ, N
COMPLEX*16 AP( * ), Q( LDQ, * ), TAU( * ), WORK( * )
PURPOSE
ZUPGTR generates a complex unitary matrix Q which is defined as the product of n1 elemen
tary reflectors H(i) of order n, as returned by ZHPTRD using packed storage: if UPLO =
'U', Q = H(n1) . . . H(2) H(1),
if UPLO = 'L', Q = H(1) H(2) . . . H(n1).
ARGUMENTS
UPLO (input) CHARACTER*1
= 'U': Upper triangular packed storage used in previous call to ZHPTRD; = 'L':
Lower triangular packed storage used in previous call to ZHPTRD.
N (input) INTEGER
The order of the matrix Q. N >= 0.
AP (input) COMPLEX*16 array, dimension (N*(N+1)/2)
The vectors which define the elementary reflectors, as returned by ZHPTRD.
TAU (input) COMPLEX*16 array, dimension (N1)
TAU(i) must contain the scalar factor of the elementary reflector H(i), as
returned by ZHPTRD.
Q (output) COMPLEX*16 array, dimension (LDQ,N)
The NbyN unitary matrix Q.
LDQ (input) INTEGER
The leading dimension of the array Q. LDQ >= max(1,N).
WORK (workspace) COMPLEX*16 array, dimension (N1)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
LAPACK version 3.0 15 June 2000 ZUPGTR(l) 
