sorgtr.f3

!>
!> SORGTR generates a real orthogonal matrix Q which is defined as the
!> product of n-1 elementary reflectors of order N, as returned by
!> SSYTRD:
!>
!> if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),
!>
!> if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).
!> 

UPLO

!>          UPLO is CHARACTER*1
!>          = 'U': Upper triangle of A contains elementary reflectors
!>                 from SSYTRD;
!>          = 'L': Lower triangle of A contains elementary reflectors
!>                 from SSYTRD.
!> 

N

!>          N is INTEGER
!>          The order of the matrix Q. N >= 0.
!> 

A

!>          A is REAL array, dimension (LDA,N)
!>          On entry, the vectors which define the elementary reflectors,
!>          as returned by SSYTRD.
!>          On exit, the N-by-N orthogonal matrix Q.
!> 

LDA

!>          LDA is INTEGER
!>          The leading dimension of the array A. LDA >= max(1,N).
!> 

TAU

!>          TAU is REAL array, dimension (N-1)
!>          TAU(i) must contain the scalar factor of the elementary
!>          reflector H(i), as returned by SSYTRD.
!> 

WORK

!>          WORK is REAL array, dimension (MAX(1,LWORK))
!>          On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
!> 

LWORK

!>          LWORK is INTEGER
!>          The dimension of the array WORK. LWORK >= max(1,N-1).
!>          For optimum performance LWORK >= (N-1)*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.
!> 

INFO

!>          INFO is INTEGER
!>          = 0:  successful exit
!>          < 0:  if INFO = -i, the i-th argument had an illegal value
!> 

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