CRPropa

“CRPropa is a numerical framework developped mostly at the APC, and whose goal is to simulate the propagation of UHECRs and their secondaries on large distances.”

First follow setup directions here. You will need to have the following installed: ROOT and CLHEP.

1. Get source and unpack it.
2. Configure: $ ./configure –prefix=$EXTDIR -with-cfitsio-include=$EXTDIR/include –with-cfitsio-library=$EXTDIR/lib –with-root=$ROOTSYS
3. Make: $ make -j2
4. Test: $ make check
5. Install: $ make install

Here is a block quote version for easier cut/pasting:

./configure --prefix=$EXTDIR -with-cfitsio-include=$EXTDIR/include --with-cfitsio-library=$EXTDIR/lib --with-root=$ROOTSYS
make -j 2
make check
make install

Direct dependencies:
ROOT
CLHEP