!>
!> ZTREXC reorders the Schur factorization of a complex matrix
!> A = Q*T*Q**H, so that the diagonal element of T with row index IFST
!> is moved to row ILST.
!>
!> The Schur form T is reordered by a unitary similarity transformation
!> Z**H*T*Z, and optionally the matrix Q of Schur vectors is updated by
!> postmultiplying it with Z.
!> 

COMPQ

!>          COMPQ is CHARACTER*1
!>          = 'V':  update the matrix Q of Schur vectors;
!>          = 'N':  do not update Q.
!> 

N

!>          N is INTEGER
!>          The order of the matrix T. N >= 0.
!>          If N == 0 arguments ILST and IFST may be any value.
!> 

T

!>          T is COMPLEX*16 array, dimension (LDT,N)
!>          On entry, the upper triangular matrix T.
!>          On exit, the reordered upper triangular matrix.
!> 

LDT

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

Q

!>          Q is COMPLEX*16 array, dimension (LDQ,N)
!>          On entry, if COMPQ = 'V', the matrix Q of Schur vectors.
!>          On exit, if COMPQ = 'V', Q has been postmultiplied by the
!>          unitary transformation matrix Z which reorders T.
!>          If COMPQ = 'N', Q is not referenced.
!> 

LDQ

!>          LDQ is INTEGER
!>          The leading dimension of the array Q.  LDQ >= 1, and if
!>          COMPQ = 'V', LDQ >= max(1,N).
!> 

IFST

!>          IFST is INTEGER
!> 

ILST

!>          ILST is INTEGER
!>
!>          Specify the reordering of the diagonal elements of T:
!>          The element with row index IFST is moved to row ILST by a
!>          sequence of transpositions between adjacent elements.
!>          1 <= IFST <= N; 1 <= ILST <= N.
!> 

INFO

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

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