LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  cungtr (UPLO, N, A, LDA, TAU, WORK, LWORK, INFO) 
CUNGTR 
subroutine cungtr  (  character  UPLO, 
integer  N,  
complex, dimension( lda, * )  A,  
integer  LDA,  
complex, dimension( * )  TAU,  
complex, dimension( * )  WORK,  
integer  LWORK,  
integer  INFO  
) 
CUNGTR
Download CUNGTR + dependencies [TGZ] [ZIP] [TXT]CUNGTR generates a complex unitary matrix Q which is defined as the product of n1 elementary reflectors of order N, as returned by CHETRD: if UPLO = 'U', Q = H(n1) . . . H(2) H(1), if UPLO = 'L', Q = H(1) H(2) . . . H(n1).
[in]  UPLO  UPLO is CHARACTER*1 = 'U': Upper triangle of A contains elementary reflectors from CHETRD; = 'L': Lower triangle of A contains elementary reflectors from CHETRD. 
[in]  N  N is INTEGER The order of the matrix Q. N >= 0. 
[in,out]  A  A is COMPLEX array, dimension (LDA,N) On entry, the vectors which define the elementary reflectors, as returned by CHETRD. On exit, the NbyN unitary matrix Q. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. LDA >= N. 
[in]  TAU  TAU is COMPLEX array, dimension (N1) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CHETRD. 
[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 >= N1. For optimum performance LWORK >= (N1)*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 had an illegal value 
Definition at line 124 of file cungtr.f.