LAPACK  3.4.2 LAPACK: Linear Algebra PACKage
cunglq.f File Reference

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## Functions/Subroutines

subroutine cunglq (M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
CUNGLQ

## Function/Subroutine Documentation

 subroutine cunglq ( integer M, integer N, integer K, complex, dimension( lda, * ) A, integer LDA, complex, dimension( * ) TAU, complex, dimension( * ) WORK, integer LWORK, integer INFO )

CUNGLQ

Download CUNGLQ + dependencies [TGZ] [ZIP] [TXT]
Purpose:
CUNGLQ generates an M-by-N complex matrix Q with orthonormal rows,
which is defined as the first M rows of a product of K elementary
reflectors of order N

Q  =  H(k)**H . . . H(2)**H H(1)**H

as returned by CGELQF.
Parameters:
 [in] M M is INTEGER The number of rows of the matrix Q. M >= 0. [in] N N is INTEGER The number of columns of the matrix Q. N >= M. [in] K K is INTEGER The number of elementary reflectors whose product defines the matrix Q. M >= K >= 0. [in,out] A A is COMPLEX array, dimension (LDA,N) On entry, the i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGELQF in the first k rows of its array argument A. On exit, the M-by-N matrix Q. [in] LDA LDA is INTEGER The first dimension of the array A. LDA >= max(1,M). [in] TAU TAU is COMPLEX array, dimension (K) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGELQF. [out] WORK WORK is COMPLEX array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. [in] LWORK LWORK is INTEGER The dimension of the array WORK. LWORK >= max(1,M). For optimum performance LWORK >= M*NB, where NB is the optimal blocksize. If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA. [out] INFO INFO is INTEGER = 0: successful exit; < 0: if INFO = -i, the i-th argument has an illegal value
Date:
November 2011

Definition at line 128 of file cunglq.f.

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