DJLES is a MATLAB based software package that solves the Dubreil-Jacotin-Long equation, yielding a mode-one internal solitary wave.
Download the code and run one of the case files in either MATLAB or Octave. The case files take less than one minute to run on a recent desktop computer, and upon completion the code will produce a plot of the wave.
A LaTeX user guide is included, a compiled version is available here (mirror).