soliton.xmds

来自「XMDS is a code generator that integrates」· XMDS 代码 · 共 112 行

<?xml version="1.0"?>
<!--Example Exactly Solvable Coupled NLSE-->

<!-- $Id: soliton.xmds,v 1.8 2004/07/14 06:37:05 joehope Exp $ -->

<!--  Copyright (C) 2000-2004                                           -->
<!--                                                                    -->
<!--  Code contributed by Greg Collecutt, Joseph Hope and Paul Cochrane -->
<!--                                                                    -->
<!--  This file is part of xmds.                                        -->
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<!--  This program is free software; you can redistribute it and/or     -->
<!--  modify it under the terms of the GNU General Public License       -->
<!--  as published by the Free Software Foundation; either version 2    -->
<!--  of the License, or (at your option) any later version.            -->
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<!--  This program is distributed in the hope that it will be useful,   -->
<!--  but WITHOUT ANY WARRANTY; without even the implied warranty of    -->
<!--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the     -->
<!--  GNU General Public License for more details.                      -->
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<!--  You should have received a copy of the GNU General Public License -->
<!--  along with this program; if not, write to the Free Software       -->
<!--  Foundation, Inc., 59 Temple Place - Suite 330, Boston,            -->
<!--  MA  02111-1307, USA.                                              -->

<simulation>

  <!-- Global system parameters and functionality -->
  <name>soliton</name>

  <author>Unknown Author</author>
  <description>
    Example of an exactly solvable coupled nonlinear Schroedinger
    equation.  Describes solition formation.
  </description>

  <prop_dim>z</prop_dim>
  <error_check>yes</error_check>
  <stochastic>no</stochastic>
  
  <!-- Global variables for the simulation -->
  <globals>
  <![CDATA[
    const double alpha = 1;
    const double beta = 1;
  ]]>
  </globals>
  
  <!-- Field to be integrated over -->
  <field>
    <name> main </name>
    <dimensions> t    </dimensions>
    <lattice>    50   </lattice>
    <domains>  (-5,5) </domains>
    <samples> 1 </samples>
    <vector>
      <name> main </name>
      <type> complex </type>
      <components>u v</components>
      <fourier_space>no</fourier_space>
      <![CDATA[
        u = complex(exp(-t*t/alpha/alpha/4),0);
        v = complex(exp(-t*t/beta/beta/4),0);
      ]]>
    </vector>
  </field>
  
  <!-- The sequence of integrations to perform -->
  <sequence>
    <integrate>
      <algorithm>RK4IP</algorithm>
      <interval>10</interval>
      <lattice>2400</lattice>
      <samples>30</samples>
      
      <k_operators>
        <constant>yes</constant>
        <operator_names>L</operator_names>
        <![CDATA[
          L = i*(-kt*kt/2);
        ]]>
      </k_operators>
      
      <iterations>3</iterations>
      <![CDATA[
        const double density = u.re*u.re+u.im*u.im+v.re*v.re+v.im*v.im;
        
        du_dz = L[u] + i*u*density;
        dv_dz = L[v] + i*v*density;
      ]]>
    </integrate>
  </sequence>
  
  <!-- The output to generate -->
  <output format="ascii" precision="double">
    <group>
      <sampling>
        <fourier_space> no </fourier_space>
        <lattice>       25  </lattice>
        <moments>ure uim vre vim</moments>
        <![CDATA[
          ure = u;
          uim = -i*u;
          vre = v;
          vim = -i*v;
        ]]>
      </sampling>
    </group>
  </output>
</simulation>