LEMS Reference Implementation
To illustrate the concepts of LEMS and to facilitate building, validating and execting models specified in the format, a Reference Implementation in Java has been created.
The implementation will process and run models defined using the proposed elements. It is mainly focused on model processing and validation. In particular, as well as handling type and component inheritance, it performs dimensionality checks on all equations to identify any inconsistencies.
It has a limited ability to run models, but only with the simplest possible (forward Euler) integration scheme. It doesn't do any symbolic manipulations and expressions are evaluated by visiting their parse trees.
After running a model, it opens a window to display the results and only exits when this window is closed. The image below shows traces of the V and U state variables from 2 instances of the Izhikevich cell model specified in LEMS and run using the interpreter.

Installation of LEMS Reference Implementation
Install Java J2SE 5 or higher. Available here. It's better to download the JDK (Java Development Kit), which includes the command line tools for compiling Java.
To try LEMS out, all you need is the executable jar file:
Just download this file and run:java -jar lems-x.x.x.jar model.xml
Source code installation with examples
If you do not have Subversion installed, it may be simplest to download the latest code, unzip the file, and run the code as described below.
Alternatively, check out the latest version of the code (from the NeuroML SourceForge SVN repository) using:
svn co https://neuroml.svn.sourceforge.net/svnroot/neuroml/LEMS cd LEMS
To compile the code it's best to install Ant (see below), but the code can be compiled using:
./make.sh (Linux or Mac) make.bat (Windows)
The standard examples can be found in the examples directory. These can be run using:
./lems examples/example1.xml (Linux or Mac) lems.bat examples\example5.xml (Windows)
If Apache Ant is installed, the options for compiling/running examples with this include:
ant (build the main jar file) ant ex1 (run the main examples ex1 to ex8) ant test (perform a number of tests including running all examples) ant -p (list all options)
A number of links to examples showing the core behaviour of LEMS is available in the left column.