Clawpack Quickstart guide

See also:

• Clawpack Documentation

If you use using the class VM, the Clawpack software is in the directory clawpack-4.x. If you are using it on your own computer, see the Installation instructions.

Open a terminal and do (the first $ indicates the Linux prompt):

$ cd $CLAW

This should take you into the directory clawpack-4.x. (The environment variable $CLAW should already be set properly on the VM.)

To try out an advection example:

$ cd apps/advection/1d/example1
$ make .plots

With luck this will automatically do the following:

• Compile the Fortran code
• Create some files ending with extension .data that are needed by the Fortran code. (Based on parameter values set in the Python script setrun.py)
• Run the Fortran code and produce a directory named _output that has the solution at various times from the computation.
• Run a plotting program to produce a directory named _plots that contains images *.png of the solution at various times and files *.html that allow you to easily view these images. Exactly what is plotted is determined by the file setplot.py.

If you now give the command:

$ firefox _plots/_PlotIndex.html

you should be able to view these plots.

Changing parameters

To try changing a parameter, edit the file setrun.py and then type:

$ make .plots

and reload the plot file in firefox.

Some things you might try changing:

• clawdata.order Change the value to 1 for the first order upwind method.
• clawdata.mthbc_xlower and clawdata.mthbc_xupper. Change both values to 2 to impose periodic boundary conditions.
• clawdata.tfinal determines the final time you solve to.

Next steps

The directory $CLAW/apps contains a number of other applications you might want to experiment with. You might next look at the acoustics examples in $CLAW/apps/acoustics/1d/example1.

Note that the Riemann solver used for each case is in a Fortran file in the corresponding directory with the name rp1.f.

See the Clawpack Documentation for more information about changing parameters and plotting the results.