atomlaser.xmds

XMDS is a code generator that integrates equations. You write them down in human readable form in a

<?xml version="1.0"?>
<!-- Stochastic atom laser simulation -->

<!-- $Id: atomlaser.xmds,v 1.21 2004/11/02 22:51:34 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.                      -->
<!--                                                                    -->
<!--  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>atomlaser</name> 

    <author>Joseph Hope</author>
    <description>
      Stochastic atom laser simulation
    </description>

    <stochastic>no</stochastic> 
    <prop_dim>t</prop_dim>
    <use_mpi>no</use_mpi>
    <error_check>yes</error_check>
    <bing>yes</bing>
    <use_wisdom>yes</use_wisdom>        <!-- Default is no -->

    <benchmark>yes</benchmark>          <!-- Default is no -->
    <use_prefs>yes</use_prefs>           <!-- Default is yes -->

    <!-- Command line arguments -->
    <argv>
	<arg>
	    <name>kick</name>
	    <type>double</type>
	    <default_value>-1.0e6</default_value>
	</arg>
	<arg>
	    <name>kappamax</name>
	    <type>double</type>
	    <default_value>1.0e2</default_value>
	</arg>
    </argv>
    
    <!-- Global variables for the simulation -->
    <globals>
	<![CDATA[
	    /* physical constants  */
	    const double omegax = 25;
	    const double g = 9.8;
	    // const double kappamax = 1.0e2; // now in <argv> tags
	    // const double kick = -1.0e6;    // now in <argv> tags
	    const double hbar = 1.05500000000e-34;
	    const double M = 1.409539200000000e-25;

	    /* absorbing boundary constants */
	    const double dpow = 1;
	    const double absorbleft = 4.0e4/pow(2.,dpow);
	    const double absorbright = 4.0e4/pow(2.,dpow);
	    const double xleft = -7.0e-5;
	    const double widthl = 3.0e-5;
	    const double xright = 5.0e-5;
	    const double widthr = 3.0e-5;
	    
	    /* numerical shift constant  */
	    const double ko=-2.5e7;
	    ]]>
    </globals>  

    <!-- Field to be integrated over -->
    <field>
	<name>main</name>
	<dimensions>     x      </dimensions>
	<lattice>      2048     </lattice>
	<domains>(-1.0e-4,8.0e-5)</domains>
	<samples>1</samples>

	<vector>
	    <name>main</name>
	    <type>complex</type>
	    <components>phi</components>
	    <fourier_space> no </fourier_space>
	    <!-- <filename format="ascii"> atomlaserinput.dat </filename> -->
	    <![CDATA[
		const double realfn = pow(M*omegax/M_PI/hbar,1/4.0)*exp(-x*x*M*omegax/2/hbar);
		phi = realfn*c_exp(rcomplex(0,(kick-ko)*x));
		]]>
	</vector>

	<vector>
	    <name> vc1 </name>
	    <type>double</type>
	    <components>V damping</components>
	    <fourier_space> no </fourier_space>
	    <![CDATA[
		V = M*g*x/hbar;
		damping = x<xleft ? -absorbleft*pow(1-cos(M_PI*(xleft-x)/widthl),dpow)
				  : ( x>xright ? -absorbright*pow(1-cos(M_PI*(x-xright)/widthr),dpow): 0);   
		]]>
	</vector>
    </field>

    <!-- The sequence of integrations to perform -->
    <sequence>
	<integrate>
	    <algorithm>RK4IP</algorithm>
	    <interval>1.0e-7</interval>
	    <lattice>1600</lattice>
	    <samples>4</samples>

	    <k_operators>
		<constant>yes</constant>
		<operator_names>KE</operator_names>
		<![CDATA[
		    KE = rcomplex(0,-hbar/M/2*(kx+ko)*(kx+ko));
		    ]]>
	    </k_operators>

	    <vectors> main vc1 </vectors>
	    <![CDATA[
		dphi_dt = KE[phi] +(damping-i*V)*phi;
		]]>
	</integrate>
    </sequence>

    <!-- The output to generate -->
    <!-- precision="double|single" (double is default option) -->
    <output format="binary">
        <!-- enabled="yes|no" (yes is default option) -->
        <breakpoint enabled="yes">
	    <!-- should the filename be some default name?? -->
	    <!-- A: yes.  <simname>_break.dat -->
	    <!-- status="unknown|old|new" -->
	    <!-- "unknown" : breakpoint input may exist, but not necessarily (default option) -->
	    <!-- "old" : breakpoint input must exist, barf if not found -->
	    <!-- "new" : breakpoint input not used, input file overwritten if exists -->
	    <!-- format="binary|ascii" (binary is default option) -->
	    <filename status="new" format="ascii">atomlaser_break.dat</filename>
	</breakpoint>
	<group>
	    <sampling>
		<fourier_space>no</fourier_space>
		<lattice>2048</lattice>
		<moments>phir phii</moments>
		<![CDATA[
		    phir = phi;
		    phii = -i*phi;
		    ]]>
	    </sampling>
	</group>
    </output>
</simulation>