zupgtr (l)  Linux Manuals
zupgtr: generates a complex unitary matrix Q which is defined as the product of n1 elementary reflectors H(i) of order n, as returned by ZHPTRD using packed storage
NAME
ZUPGTR  generates a complex unitary matrix Q which is defined as the product of n1 elementary reflectors H(i) of order n, as returned by ZHPTRD using packed storageSYNOPSIS
 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 elementary reflectors H(i) of order n, as returned by ZHPTRD using packed storage: if UPLO = aqUaq, Q = H(n1) . . . H(2) H(1),if UPLO = aqLaq, Q = H(1) H(2) . . . H(n1).
ARGUMENTS
 UPLO (input) CHARACTER*1
 = aqUaq: Upper triangular packed storage used in previous call to ZHPTRD; = aqLaq: 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