RAMSES/ATON
===========

Coupled hydro and radiation using the GPU for cosmological simulations.


Compilation
-----------

The program is compiled in two parts: first libaton, then ramses.

1. For libaton, edit aton/atonlib/Makefile and set the variables as
described in the file. In particular, the grid size for aton has to be
chosen at compile time by setting the NCELLX, NCELLY and NCELLZ variables.
For the first test, use 32x32x32.

$ cd aton/atonlib
$ vim Makefile  # edit the options
$ make

This will produce a file called aton/atonlib/libaton.a.

2. For ramses, edit bin/Makefile. Set the following variables:
ATON_FLAGS = -DATON
NVAR = 6
LIBCUDA = flags for your CUDA libraries
You may need to add -lmpi_cxx to LIBMPI.
Then build the "ramses_aton" target:

$ cd bin
$ vim Makefile  # edit the options
$ make ramses_aton

This will produce a binary called bin/ramses3d


Testing
-------

There is a small 32^3 test case to check that the program built correctly.


1. First compile the amr2cell utility:

$ cd utils/f90
$ vim Makefile  # edit the options
$ make amr2cell

This will produce a binary called utils/f90/amr2cell


2. Then run the test:

$ aton/sims/testing/run_and_analyze.sh

This runs the code on a 32^3 grid with 1 node.
It takes about half an hour to run.
It produces a  file called test/profile.txt.
You should compare this to test/expected_profile.txt using a
plotting program like gnuplot.


Larger test
-----------

For a larger test, we can run Iliev Test 5 on a 256^3 grid with 16 nodes.

1. Modify the aton grid size in aton/atonlib/Makefile:

NCELLX=128
NCELLY=128
NCELLZ=64

2. Recompile:

$ cd aton/atonlib
$ vim Makefile  # set the grid size
$ make clean
$ make
$ cd ../../bin
$ make ramses_aton
$ cd ..

This will produce a new bin/ramses3d binary.

3. Launch the simulation:

$ mkdir test5
$ cd test5
$ mpirun -n 16 ../bin/ramses3d ../aton/sims/iliev_tests/5/test5_aton.nml > log

This will take several hours to run.
It will produce 7 output directories and a file called "averages.txt".
Follow the analysis commands in aton/sims/testing/run_and_analyze.sh
to produce profile.txt. It can be compared to Fig. 11-15 of arXiv:0905.2920v1.
It's a more accurate version of aton/sims/testing/expected_profile.txt.


Cosmological simulation
-----------------------

Running a 256^3 cosmo simulation is similar to Iliev Test 5 from the
previous section.
Use this namelist: aton/sims/cosmo256/noamr/rad_aton.nml
You need to generate initial conditions from grafic first.