SRC/ztrexc.f(3)            Library Functions Manual            SRC/ztrexc.f(3)

NAME
       SRC/ztrexc.f

SYNOPSIS
   Functions/Subroutines
       subroutine ztrexc (compq, n, t, ldt, q, ldq, ifst, ilst, info)
           ZTREXC

Function/Subroutine Documentation
   subroutine ztrexc (character compq, integer n, complex*16, dimension( ldt,
       * ) t, integer ldt, complex*16, dimension( ldq, * ) q, integer ldq,
       integer ifst, integer ilst, integer info)
       ZTREXC

       Purpose:


            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.

       Parameters
           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

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 125 of file ztrexc.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/ztrexc.f(3)