cupgtr (l)  Linux Manuals
cupgtr: generates a complex unitary matrix Q which is defined as the product of n1 elementary reflectors H(i) of order n, as returned by CHPTRD using packed storage
NAME
CUPGTR  generates a complex unitary matrix Q which is defined as the product of n1 elementary reflectors H(i) of order n, as returned by CHPTRD using packed storageSYNOPSIS
 SUBROUTINE CUPGTR(
 UPLO, N, AP, TAU, Q, LDQ, WORK, INFO )
 CHARACTER UPLO
 INTEGER INFO, LDQ, N
 COMPLEX AP( * ), Q( LDQ, * ), TAU( * ), WORK( * )
PURPOSE
CUPGTR generates a complex unitary matrix Q which is defined as the product of n1 elementary reflectors H(i) of order n, as returned by CHPTRD 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 CHPTRD; = aqLaq: Lower triangular packed storage used in previous call to CHPTRD.
 N (input) INTEGER
 The order of the matrix Q. N >= 0.
 AP (input) COMPLEX array, dimension (N*(N+1)/2)
 The vectors which define the elementary reflectors, as returned by CHPTRD.
 TAU (input) COMPLEX array, dimension (N1)
 TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CHPTRD.
 Q (output) COMPLEX 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 array, dimension (N1)
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value