SRC/zung2r.f(3) Library Functions Manual SRC/zung2r.f(3)

SRC/zung2r.f


subroutine zung2r (m, n, k, a, lda, tau, work, info)
ZUNG2R

ZUNG2R

Purpose:

 ZUNG2R generates an m by n complex matrix Q with orthonormal columns,
 which is defined as the first n columns of a product of k elementary
 reflectors of order m
       Q  =  H(1) H(2) . . . H(k)
 as returned by ZGEQRF.

Parameters

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 i-th column must contain the vector which
          defines the elementary reflector H(i), for i = 1,2,...,k, as
          returned by ZGEQRF in the first 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 ZGEQRF.

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

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 113 of file zung2r.f.

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