XML Schema for Monte Carlo simulations

The complexity of developing XML schemas for physics simulations forces us to split the project into smaller pieces and to first identify those areas where common ground between many applications can be found.

Once we get to higher level structures, such as the input or output of whole programs, individual applications
often tend to differ too much for a common schema to make sense. However for a limited class of applications, such as, e.g. Monte Carlo simulations, or even more specific, such as Monte Carlo simulations on lattice models, a common data format can make much sense, as it allows common evaluation or archiving solutions to be created. Here we thus present a simple first draft of a schema for Monte Carlo simulations, based on the parameter , random number generator , lattice, and Monte Carlo averages schemas presented before.

Schema for Monte Carlo simulations
Documentation created by XML Spy
XSLT style file for simple viewing in an XSLT supporting web browser
An example file which can be viewed using the XSLT style file

The main structure of the proposed schema is:

<SIMULATION>
  <PARAMETERS>
    <PARAMETER name="lattice">square</PARAMETER>
    <PARAMETER name="L">10<>/PARAMETER>
  </PARAMETERS>
  <AVERAGES> 
    ...
  </AVERAGES>
  <MCRUN>
    ...
  </MCRUN>
  <MCRUN>
    ...
  </MCRUN>
</SIMULATION>

The PARAMETERS element contains a list of parameters , and the AVERAGES section results of Monte Carlo measurements , as discussed in the other sections.

The main new element which needs some discussion is MCRUN. Monte Carlo simulations can trivially be parallelized by starting them on different nodes with different random seeds. Each MCRUN element describes a single of these
parallel Monte carlo runs:

  <MCRUN>
    <RNG>
      ...
    </RNG>
    <EXECUTED>
      <FROM>Wed Aug 22 18:53:39 2001</FROM>
      <TO>Wed Aug 22 18:53:39 2001</TO>
      <MACHINE><NAME>ogdoad.ethz.ch</NAME></MACHINE>
    </EXECUTED>
    <EXECUTED>
      <FROM>Wed Aug 22 18:53:40 2001</FROM>
      <TO>Wed Aug 22 18:53:40 2001</TO>
      <MACHINE><NAME>ogdoad.ethz.ch</NAME></MACHINE>
    </EXECUTED>
    <AVERAGES>
      ...
    </AVERAGES>
  </MCRUN>

The RNG element describes the random seed used for this particular run, the EXECUTED elements information about when and where the simulation was performed, and the AVERAGES element the Monte Carlo measurements for this particular run.

For a full example of a real simulation see this example .

The above schema is the current draft which we use to archive our results. We expect it to change and grow as we interact with others to find a common useful format. We encourage your comments and ideas .

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