nlse.xmds

来自「XMDS is a code generator that integrates」· XMDS 代码 · 共 129 行

<?xml version="1.0"?>
<!--Example simulation: Non-Linear Schroedinger Equation-->

<!-- $Id: nlse.xmds,v 1.11 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.                                        -->
<!--                                                                    -->
<!--  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.            -->
<!--                                                                    -->
<!--  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>nlse</name>

  <author>Unknown Author</author>
  <description>
    Example simulation of the nonlinear Schroedinger equation
  </description>

  <prop_dim>z</prop_dim>
  <error_check>yes</error_check>
  <stochastic>no</stochastic>

  <!-- Command line arguments -->
  <argv>
    <arg>
      <name>energy</name>
      <type>double</type>
      <default_value>4.0</default_value>
    </arg>
    </argv>

  <!-- Global variables for the simulation -->
  <globals>
  <![CDATA[
    // const double energy = 4.0;  // is now an argument
    const double vel = 0.0;
    const double hwhm = 1.0;
  ]]>
  </globals>

  <!-- Field to be integrated over -->
  <field>
    <name>main</name>
    <dimensions>  t   </dimensions>
    <lattice>    100  </lattice>
    <domains>  (-5,5) </domains>

    <samples>1</samples>
    <vector>
      <name>main</name>
      <type>complex</type>
      <components>phi</components>
      <fourier_space>no</fourier_space>
      <![CDATA[
        const double w0 = hwhm*sqrt(2/log(2.0));
        const double amp  = sqrt(energy/w0/sqrt(M_PI/2));
      
        phi = pcomplex(amp*exp(-t*t/w0/w0),vel*t);
      ]]>
    </vector>
    <vector>
      <name>vc1</name>
      <type>double</type>
      <components>damping</components>
      <fourier_space>no</fourier_space>
      <![CDATA[
        damping=1.0*(1-exp(-pow(t*t/4/4,10)));
      ]]>
    </vector>

  </field>

  <!-- The sequence of integrations to perform -->
  <sequence>
    <integrate>

      <algorithm>RK4IP</algorithm>
      <interval>20</interval>
      <lattice>1000</lattice>
      <samples>50</samples>
      <k_operators>
        <constant>yes</constant>
        <operator_names>L</operator_names>
        <![CDATA[
          L = rcomplex(0,-kt*kt/2);
        ]]>
      </k_operators>
      <vectors>main vc1</vectors>
      <![CDATA[
        dphi_dz =  L[phi] + i*~phi*phi*phi - phi*damping;
      ]]>
    </integrate>
  </sequence>

  <!-- The output to generate -->
  <output format="ascii" precision="double">
    <filename>nlse.xsil</filename>
    <group>
      <sampling>
        <fourier_space> no </fourier_space>
        <lattice>       50 </lattice>
        <moments>pow_dens</moments>
        <![CDATA[
          pow_dens=~phi*phi;
        ]]>
      </sampling>
    </group>
  </output>

</simulation>