zupgtr (l) - Linux Manuals
zupgtr: generates a complex unitary matrix Q which is defined as the product of n-1 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 n-1 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 n-1 elementary reflectors H(i) of order n, as returned by ZHPTRD using packed storage: if UPLO = aqUaq, Q = H(n-1) . . . H(2) H(1),if UPLO = aqLaq, Q = H(1) H(2) . . . H(n-1).
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 (N-1)
- 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 N-by-N unitary matrix Q.
- LDQ (input) INTEGER
- The leading dimension of the array Q. LDQ >= max(1,N).
- WORK (workspace) COMPLEX*16 array, dimension (N-1)
- INFO (output) INTEGER
-
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value