back up next contents bibliography JBONE applet: execution

Resources:   applet   --   execution   --   programing   --   variable index   --   source code

The JBONE applet is a pedagogical tool showing the time evolution of various one dimensional differential equations solved with different methods. Tag modifiers define the default behaviour of an applet: the selectors on the top of the applet switch between different types of simulations and the parameters on the right attribute specific values.

Execute.
Press the Start / Stop button to execute the JBONE applet until the value of the Time reaches the value RunTime or Step 1 to take unit steps of a duration TimeStep. Different functions are evolved (depending on the simulation) and are displayed in the plot window; approximative measurements can be read from the browser status bar after clicking in the plot window and are also printed to the Java console. More precision is obtained by pressing the Print Console button and reading the numerical output from the Java console.

Selectors.
The selectors appearing on the top of JBONE define the type of problem. They are initialized with default values and are later modified to fit the values specified in the Tag window. Careful, white spaces count!

  • method selects the numerical method. Choices include
    "Finite differences", "Finite elements", "Fourier transform", "Lagrangian methods", "Particle methods","Particle methods*", "Sampling methods"."Sampling methods*".
  • scheme selects a particular scheme in a given method. Choices include
    "Standard scheme", "Explicit 2-level", "Explicit 3-level", "Implicit 2-level", "Expl-LaxWendroff", "Impl-LaxWendroff", "Lax-Friedrichs", "Leap-frog (FDTD)", "European naive", "European vanilla", "American naive", "American vanilla", "Tune Integration", "Expanded convol.", "Aliased convol.", "CubicHermite FEM", "Cubic--Splines", "MC norm. walk", "MC log-normal", "My scheme", "Exercise 2.01", "Exercise 2.03", etc
  • ic selects the type of initial condition. Choices include
    "Box", "Gaussian", "Cosine", "Soliton", "WavePacket", "PutOption".
  • pde selects the master differential equation. Choices include
    "Advection", "Burger (shock)", "KdV (solitons)", "Schroedinger", "Black-Scholes", "My equation 1", "My equation 2", "Exercise".

Run parameters.
The parameters appearing in a list on the right side of the JBONE applet are initialized with default values and are later modified to fit the values specified in the Tag window. They can be modified even later at run time by double-clicking the names. Note that only the parameters specified in the list of Tag modifiers (thought to be relevant) are listed. For a complete list at run-time, switch the selector from Double click below to Show all parameters.

  • Velocity the advection velocity (or the market interest rate)
  • Diffusion the diffusion (or the market volatility)
  • Dispersion the dispersion
  • TimeStep the time step
  • MeshPoints the number of mesh points
  • Walkers the number of particles
  • TimeImplicit the time implicit parameter
  • TuneIntegr the tunable integration parameter
  • ICAmplitude the initial condition amplitude
  • ICPosition the initial condition position
  • ICWidth the initial condition width
  • ICWavelength the initial condition wavelength
  • RunTime the physical run time
  • MeshLeft the left position of the mesh
  • MeshLength the length of the simulation box
  • PhysDataCase the type of Physical Data, e.g potential shape
  • PhysDataValue a Physical Data parameter, e.g potential amplitude

HTML TAG modifiers format.
The JBONE applet is insearted in an HTML document via the Tag window using a header of the form

<applet codebase="$user_dir/applet/" code=jbone
    align=center width=780 height=400>
    <param name=Velocity            value=0.>
    <param name=Diffusion           value=0.>
    <param name=Dispersion          value=0.>
    <param name=TimeStep            value=0.5>
    <param name=MeshPoints          value=64>
    <param name=Walkers             value=0>
    <param name=TimeImplicit        value=0.7>
    <param name=TuneIntegr          value=0.333>
    <param name=ICAmplitude         value=1.>
    <param name=ICPosition          value=18.>
    <param name=ICWidth             value=8.>
    <param name=ICWavelength        value=4.>
    <param name=RunTime             value=128.>
    <param name=MeshLeft            value=0.>
    <param name=MeshLength          value=64.>
    <param name=PhysDataCase        value=1>
    <param name=PhysDataValue       value=1.>
    <param name=method              value="Finite differences">
    <param name=scheme              value="Exercise 2.01">
    <param name=ic                  value="Gaussian">
    <param name=pde                 value="Exercise">
</applet>
The first two lines specify the path name on the server, the position and the size of the window. The Tag modifiers that follow attribute the values that will be set when the applet first appears in the web page. These can always be recovered simply by refreshing the webpage.

      
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