View source for Philosophy of examples and how to run them

Go back to [[Medusa#Examples|Examples]].

The idea of our examples is to present the functionality of the library in an accessible and incremental manner. 
The examples present different solutions to problems ranging in difficulty from the simple [[Poisson's equation]] to more specific examples, such as [[Fluid mechanics]].
Each examples consists of a name, e.g. <code>poisson_dirichlet_2D</code> and its corresponding
* source code, e.g. <code>poisson_dirichlet_2D.cpp</code>
* plot script, e.g. <code>poisson_dirichlet_2D.m</code>
Additional appropriately named input files might be present for more complicated examples and similarly named output files might be produced. 
The examples and their plot scripts are intended to work out of the box,  so the reader can simply run the examples on their machine.
The procedure for running examples is simple and the same for all examples. The accompanying plot scripts can be run with Matlab or octave and 
they produce the figures the reader sees in the Examples category of this wiki.

Let us now illustrate the process of running an example <code>poisson_dirichlet_2D</code>. 

First the example needs to be built (compiled). The building is done in the same <code>build/</code> directory
where medusa was build. To build and run the example, simply execute
<syntaxhighlight lang="bash">
make poisson_dirichlet_2D_run  # builds and runs your example          
</syntaxhighlight>
to compile and run your example. On first compilation, the whole library might compile as well, if not compiled previously, so it might take longer than usual.
Compiled binary used to run the example is placed next to the example source file. If only <code>make poisson_dirichlet_2D</code> (without _run) the
example is built, but not run.

To build all examples, you can just run 
<syntaxhighlight lang="bash">
make examples  # or "make examples_run" to also run them
</syntaxhighlight>

To run the built example again, go back to the initial folder where the source code for your example was, and run
<syntaxhighlight lang="bash">
./poisson_dirichlet_2D
</syntaxhighlight>
The output will be saved in the same folder as the binary and the source file.

After, just run the corresponding plot script <code>example_name.m</code> and you should see a figure, usually showing the solution.

'''Standalone compilation'''

The examples can then be compiled manually using e.g. <code>g++</code>, provided that
appropriate include and library paths are set and the <code>medusa_standalone</code> library is specified
for linking.

Example command to be run from <code>poisson_equation</code> directory:
<syntaxhighlight lang="bash">
g++ -o poisson_dirichlet_2D poisson_dirichlet_2D.cpp -I ../../include -Wall -O3 -L ../../bin -lmedusa_standalone
</syntaxhighlight>

The compiled example can be run simply as
<syntaxhighlight lang="bash">
./poisson_dirichlet_2D
</syntaxhighlight>
and plotted using the accompanying plot script.


Some more feature specific examples are found in the [http://e6.ijs.si/docs/ technical documentation] and in the unit tests.

Go back to [[Medusa#Examples|Examples]].