Documentation

If you want to modify the demonstrations beyond changing the parameters displayed you must download the executable PDE.jar and load a suitably modified HTML file (e.g. Test.html) into your browser or the java appletviewer. The following parameters can be set by editing the HTML file:

ParameterFunctionDefault valueNotes
functionEquation solved0See below
parameter01st parameter of equationsSet in java file
parameter12nd parameter of equationsSet in java file
...... parameter of equationsSet in java fileNumber of parameters set in java file
solvewidthNumber of mesh points in x64Must be 2n
solveheightNumber of mesh points in y64Must be 2n
dtTime step in solver0.51
meshMesh size1.
ic001st initial condition parameterSet in java fileSee below
ic012nd initial condition parameterSet in java fileSee below
plotwidthSize of plot in x256
plotheightSize of plot in y256
chooseplotsShows "Plot Type"true
plottypeInitial Plot Type0
plotFFTPlots FFTtrueOnly applies for spectral evolution
pallettePallette0If nonzero sets pallette, otherwise got from java file
scaleplotAllows plot to rescale with windowfalseOnly useful with appletviewer
scaleminmaxScales color plot with min/max valuestrue
showminmaxShows values of min/maxtrue
minimumMinimum value of color scale0Only used if scaleMinMax=false
maximumMaximum value of color scale1Only used if scaleMinMax=false
showtimeShows time of evolutiontrue
speedSets initial speed1

Any parameter that is absent in the HTML file is given the default value.

Various equations can be solved. The following table gives the equation and the corresponding java files where the evolution, default parameter, initial conditions, etc. are defined. You can add your own function using these examples as templates.

NumberEquationJava File
0Complex Ginzburg LandauCGL
1BrusselatorBrusselator
2SchnackenbergSchnackenberg
3Swift-HohenbergSH
4BarkleyBarkley
5Bar-EiswirthBar
6Lifshitz-PetrichLifshitz
72 Coupled Swift-HohenbergSH2
8FitzHugh-NagumoFHN


The initial conditions are set in the equation java files taking parameters from the HTML file. The parameter ic00 gives the value of the first parameter in the initial condition function of the first equation, ic01 gives the value of the second parameter in the initial condition function of the first equation, ic10 gives the value of the first parameter in the initial condition function of the second equation, etc. The number of initial condition parameters required is set in the java file.

The java source code is here.