.TH ZUNG2L 1 "November 2006" " LAPACK routine (version 3.1) " " LAPACK routine (version 3.1) " .SH NAME ZUNG2L - an m by n complex matrix Q with orthonormal columns, .SH SYNOPSIS .TP 19 SUBROUTINE ZUNG2L( M, N, K, A, LDA, TAU, WORK, INFO ) .TP 19 .ti +4 INTEGER INFO, K, LDA, M, N .TP 19 .ti +4 COMPLEX*16 A( LDA, * ), TAU( * ), WORK( * ) .SH 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 m .br Q = H(k) . . . H(2) H(1) .br as returned by ZGEQLF. .br .SH ARGUMENTS .TP 8 M (input) INTEGER The number of rows of the matrix Q. M >= 0. .TP 8 N (input) INTEGER The number of columns of the matrix Q. M >= N >= 0. .TP 8 K (input) INTEGER The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0. .TP 8 A (input/output) COMPLEX*16 array, dimension (LDA,N) On entry, the (n-k+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 m-by-n matrix Q. .TP 8 LDA (input) INTEGER The first dimension of the array A. LDA >= max(1,M). .TP 8 TAU (input) COMPLEX*16 array, dimension (K) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ZGEQLF. .TP 8 WORK (workspace) COMPLEX*16 array, dimension (N) .TP 8 INFO (output) INTEGER = 0: successful exit .br < 0: if INFO = -i, the i-th argument has an illegal value