LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dorgtr (UPLO, N, A, LDA, TAU, WORK, LWORK, INFO) 
DORGTR 
subroutine dorgtr  (  character  UPLO, 
integer  N,  
double precision, dimension( lda, * )  A,  
integer  LDA,  
double precision, dimension( * )  TAU,  
double precision, dimension( * )  WORK,  
integer  LWORK,  
integer  INFO  
) 
DORGTR
Download DORGTR + dependencies [TGZ] [ZIP] [TXT]DORGTR generates a real orthogonal matrix Q which is defined as the product of n1 elementary reflectors of order N, as returned by DSYTRD: 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 DSYTRD; = 'L': Lower triangle of A contains elementary reflectors from DSYTRD. 
[in]  N  N is INTEGER The order of the matrix Q. N >= 0. 
[in,out]  A  A is DOUBLE PRECISION array, dimension (LDA,N) On entry, the vectors which define the elementary reflectors, as returned by DSYTRD. On exit, the NbyN orthogonal matrix Q. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N). 
[in]  TAU  TAU is DOUBLE PRECISION array, dimension (N1) TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DSYTRD. 
[out]  WORK  WORK is DOUBLE PRECISION 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,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 dorgtr.f.