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.

M

          M is INTEGER


          The number of rows of the matrix Q. M >= 0.

N

          N is INTEGER


          The number of columns of the matrix Q. M >= N >= 0.

K

          K is INTEGER


          The number of elementary reflectors whose product defines the


          matrix Q. N >= K >= 0.

A

          A is 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

          LDA is INTEGER


          The first dimension of the array A. LDA >= max(1,M).

TAU

          TAU is COMPLEX*16 array, dimension (K)


          TAU(i) must contain the scalar factor of the elementary


          reflector H(i), as returned by ZGEQLF.

WORK

          WORK is COMPLEX*16 array, dimension (N)

INFO

          INFO is INTEGER


          = 0: successful exit


          < 0: if INFO = -i, the i-th argument has an illegal value

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

December 2016