LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  zungql (M, N, K, A, LDA, TAU, WORK, LWORK, INFO) 
ZUNGQL 
subroutine zungql  (  integer  M, 
integer  N,  
integer  K,  
complex*16, dimension( lda, * )  A,  
integer  LDA,  
complex*16, dimension( * )  TAU,  
complex*16, dimension( * )  WORK,  
integer  LWORK,  
integer  INFO  
) 
ZUNGQL
Download ZUNGQL + dependencies [TGZ] [ZIP] [TXT]ZUNGQL generates an MbyN 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.
[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. M >= N >= 0. 
[in]  K  K is INTEGER The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0. 
[in,out]  A  A is COMPLEX*16 array, dimension (LDA,N) On entry, the (nk+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 MbyN matrix Q. 
[in]  LDA  LDA is INTEGER The first dimension of the array A. LDA >= max(1,M). 
[in]  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. 
[out]  WORK  WORK is COMPLEX*16 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,N). For optimum performance LWORK >= N*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 ith argument has an illegal value 
Definition at line 129 of file zungql.f.