Running the Code

Before running the code, you must source the shell script PumiInterface/src/use_julialib.sh. This enables Julia to find and use Pumi.

cd /path/to/PumiInterface/src # for example ~/.julia/v0.4/PumiInterface/src)
source ./use_julialib.sh  # note that you must be in the same directory as the script when sourcing it

The code takes an input file that defines all options for the solver, including the which physics to solve, which mesh to use, initial conditions, boundary conditions, and discretization. The file src/input/input_vals.txt describes the input file format and all valid options.

Simple Mode

Once an input file is prepared, the solver can be invoked with

mpirun -np x julia /path/to/PDESolver/src/startup.jl "input_file_name"

This will run the solver in parallel with x processes, solving the physics specified in the input file.

Advanced Mode

The code also provides a scripting interface. This enables users to supply initial conditions and boundary conditions, as well as do advanced post-processing if desired.

The template script is:

using PDESolver  # load the interface to the code
using AdvectionEquationMod  # load the desired physics module

# register ICs and BCs here

input_fname = ARGS[1]  # use the first command line argument as the input file
                       # name

# solve the equation defined in the input file
mesh, sbp, eqn, opts = run_solver(input_fname)

# do post-processing using mesh, sbp, eqn, opts here

mesh, sbp, eqn, opts are the AbstractMesh object, the SummationByParts operator, the AbstractSolutionData, and the options dictionary, respectively.

The AbstractMesh object contains all the data about the mesh, including coordinates and mapping jacobian information. The sbp object is used for numerically approximating derivatives. The AbstractSolutionData object contains all the data about the solution and the residual of the equation. The input file gets parsed into the options dictionary, which is used to by the rest of the code.

The PDESolver module exports several functions for use by the scripting interface. The first two registerIC and registerBC allow users to supply initial conditions and boundary conditions. See the documentation of the functions for details. The functions printICNames and printBCNames print the names of all currently registers initial conditions and boundary conditions.

For example a user can, either in a Julia script or interactive (REPL) session:

using PDESolver
using AdvectionEquationMod

printBCNames(AdvectionEquationMod)

And this will print the names of all the boundary conditions currently known to the Advection Equation module.