ctrexc.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

ctrexc.f  

SYNOPSIS


 

Functions/Subroutines


subroutine ctrexc (COMPQ, N, T, LDT, Q, LDQ, IFST, ILST, INFO)
CTREXC  

Function/Subroutine Documentation

 

subroutine ctrexc (character COMPQ, integer N, complex, dimension( ldt, * ) T, integer LDT, complex, dimension( ldq, * ) Q, integer LDQ, integer IFST, integer ILST, integer INFO)

CTREXC

Purpose:

 CTREXC 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.
          If N == 0 arguments ILST and IFST may be any value.


T

          T is COMPLEX 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 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.

Date:

December 2016

Definition at line 128 of file ctrexc.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
Function/Subroutine Documentation
subroutine ctrexc (character COMPQ, integer N, complex, dimension( ldt, * ) T, integer LDT, complex, dimension( ldq, * ) Q, integer LDQ, integer IFST, integer ILST, integer INFO)
Author
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