zung2l (l)  Linux Man Pages
zung2l: generates an m by n complex matrix Q with orthonormal columns,
NAME
ZUNG2L  generates an m by n complex matrix Q with orthonormal columns,SYNOPSIS
 SUBROUTINE ZUNG2L(
 M, N, K, A, LDA, TAU, WORK, INFO )
 INTEGER INFO, K, LDA, M, N
 COMPLEX*16 A( LDA, * ), TAU( * ), WORK( * )
PURPOSE
ZUNG2L generates an m by n complex matrix Q with orthonormal columns, which is defined as the last n columns of a product of k elementary reflectors of order mQ
as returned by ZGEQLF.
ARGUMENTS
 M (input) INTEGER
 The number of rows of the matrix Q. M >= 0.
 N (input) INTEGER
 The number of columns of the matrix Q. M >= N >= 0.
 K (input) INTEGER
 The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.
 A (input/output) COMPLEX*16 array, dimension (LDA,N)
 On entry, the (nk+i)th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by ZGEQLF in the last k columns of its array argument A. On exit, the mbyn matrix Q.
 LDA (input) INTEGER
 The first dimension of the array A. LDA >= max(1,M).
 TAU (input) COMPLEX*16 array, dimension (K)
 TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ZGEQLF.
 WORK (workspace) COMPLEX*16 array, dimension (N)
 INFO (output) INTEGER

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