Provided by: liblapack-doc_3.3.1-1_all

**NAME**

LAPACK-3 - 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 m Q = H(k) . . . H(2) H(1) 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 (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. 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 i-th argument has an illegal value LAPACK routine (version 3.2) April 2011 ZUNG2L(3lapack)