ztrexc.f man page

ztrexc.f —

Synopsis

Functions/Subroutines

subroutine ztrexc (COMPQ, N, T, LDT, Q, LDQ, IFST, ILST, INFO)
ZTREXC

Function/Subroutine Documentation

subroutine ztrexc (characterCOMPQ, integerN, complex*16, dimension( ldt, * )T, integerLDT, complex*16, dimension( ldq, * )Q, integerLDQ, integerIFST, integerILST, integerINFO)

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
 postmultplying 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.

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 >= 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.

Date:

November 2011

Definition at line 125 of file ztrexc.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

ztrexc(3) is an alias of ztrexc.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK