CLAWPACK Sample Code

This code is modified from $CLAW/apps/advection/1d/example.

Advection equation $q_t + uq_x=0$.

Advection at constant velocity with periodic boundary conditions.

These parameters are specified in setrun.py [.html].

See Instructions

Plots of results

The following set of output plots are created by running the script run_tests.py [.html]:

Upwind, mx=200

Lax-Wendroff, mx=200

Minmod, mx=200

MC limter, mx=200

Upwind, mx=1000

Lax-Wendroff, mx=1000

Minmod, mx=1000

MC limter, mx=1000

Fortran files

Makefile [.html]

Determines which version of fortran files are used when compiling the code with make and specifies where output and plots should be directed. Type "make .help" at the Unix prompt for options.

setprob.f [.html]

A routine by this name is called by the library routine clawpack/1d/lib/claw1ez.f [.html] and is generally used to set any values needed for the specific problem being solved.

rp1.f [.html]

This is the Riemann solver, which takes the $q$ values stored in the arrays ql and qr and returns the waves in the array wave and speeds in the array s that result in solving the Riemann problem at each cell interface, and the fluctuations amdq and apdq. See $CLAW/doc/rp1.html for more information about 1d Riemann solvers.

qinit.f [.html]

This subroutine sets the initial data $q(x,0)$ at time $t=0$.

Python files

setrun.py [.html]

This file contains a function that specifies what run-time parameters will be used.

setplot.py [.html]

This file contains a function that specifies what plots will be done and sets various plotting parameters.

Data files

Warning: These files are generally changed when setting up a run and the versions here may not be the ones actually used.

claw.data [.html]

This file contains a number of parameter values that are used by CLAWPACK. The values in this file are read by the library routine clawpack/1d/lib/claw1ez.f [.html]. Each line contains one or more values to be read in, followed by comments that are ignored by the Fortran code but may be used by Pythons scripts.

Some parameters that you might want to modify are described in the documentation .

setprob.data [.html]

This file contains the advection velocity $u$ and various other parameters used in setting the initial conditions. Values in this file are read in by the subroutine setprob.f95 [.html].

Library routines

In addition to the Fortran routines in this library, several library routines from $CLAW/clawpack/1d/lib are used. See the Makefile [.html] to determine which ones are used.

Instructions

    $ make .output