3-Dimensional MOCASSIN (Version 2.01): MOnte CArlo SimulationS of Ionized Nebulae

Last updated: March 17th 2005

In this page, which will be forever under development, you can find some information about MOCASSIN, and all the info about how to obtain the source code. For a brief description of the scientific context of this work please look at my research interests.

MOCASSIN is made freely available under the General Public License (GPL), which requires that any changes or improvements to the code should also be made freely available.

System Requirements

MOCASSIN is written in Fortran 90, so in order to compile it and run it you will first of all need a Fortran 90 compiler. In order to speed up the computation MOCASSIN is fully parallel and it uses the Message Passing Interface (MPI) standard libraries, which are generally distributed with all commercial Fortran compilers. If no Fortran 90 compiler and/or no MPI libraries are installed on your system, they can be separately downloaded (free) from a number of site (google-search for 'free F90 Intel', and 'MPI standard download'). A multi-processor machine (beowulf cluster or shared memory architectures are both suitable) would be ideal, however a normal single-processor PC can also be used (but the time of execution will be of course longer).

MOCASSIN has been tested and benchmarked on a number of platforms, including the SGI Origin 2000 and SUN Microsystems V880 multiprocessor computers that are part of the UCL HiPerSPACE super-computing centre and the IBM RS/6000 SP machine at Peking University (info can be found here, but only in Chinese) and a number of standard linux beowulf clusters. In general the code has proved to be reasonably portable and no major problems have been encountered when installing it on a new platform. As long as the makefile is correct for the compiler used, things should go very smoothly (if you keep your fingers crossed).

Documentation

The main core and structure of MOCASSIN was developed as part of my PhD thesis at UCL. The code has changed somewhat since the completion of my course (November 2002), however the basic structure has not changed much, and you are welcome to download a copy of my thesis from this site. A brief description of MOCASSIN is also included in Ercolano et al. (2003, MNRAS,340, 1136) and Ercolano et al. (2005, MNRAS, submitted). Information on the individual files contained in the tar balls below can be found in the README file, which also contains a brief step by step tutorial on how to set up MOCASSIN to run a number of benchmark cases and general guidelines on how to set up your own simulation. However should you still have any trouble please do not hesitate to contact me.

IMPORTANT!!!!!

We have now decided to make any further versions of MOCASSIN available on request by email (be@star.ucl.ac.uk). The reason for this is so that an email address database can be contructed, making it therefore possible to let people know if any bugs are found/fixed and if any new features are added to the code. If you already have a version of MOCASSIN and you are using it then it would be great if you could send me an email so that I know and I can add your address to the list. If for any reason you'd rather not send me an email (I don't generally stalk people anyway), then please check this site regurarly for info about the code. Also if MOCASSIN is used for work in any publications, please make sure to state the version number. The version currently available is Version 2.01, and reference Ercolano et al. (2003, MNRAS,340, 1136), and Ercolano et al. (2005, MNRAS submitted).

What's New in Version 2.01

Multiple ionising sources can now be easily placed at any desired location. We refer to the Version 2.01 README file for information on new keywords.

What's New in Version 2.00

Birth of the dusty version of MOCASSIN!! Dust and gas processes are now fully integrated within the Monte Carlo transfer as described by Ercolano et al. (2005, MNRAS submitted).

Multi-grid procedures are introduced to allow multiple spatial sampling.

We refer to the Version 2.00 README file for information on new keywords.

What's New in Version 1.10

The semi-automatic bipolar structure (see README file for Version 1.01, Section 5.1) has been eliminated (any geometry can easily be created with the densityFile option). This has induced some changes in the syntax of the following keywords (please refer to Section 3.1 of the README file.): "Hdensity", "NeStart", "TeStart" . Also the keyword "mu" has of course been eliminated.

The "output" keyword has been added (see Section 3.1 of the README file); when this keyword is omitted, no output files, except for the grid files, will be written until the very last iteration. We have found that this speeds up the simulations considerably, particularly in the case of large grids.

The option "autogrid" was superflous and has been eliminated

The syntax of the option "autoPackets" has changed (see Section 3.1 of the README file).

Changed the functin of Rout keyword and quantity.

The option "planeIonization" was added (see Section 3.1 of the README file for syntax). This allows the ionization source to be extended to a plane.

Finally, all the various files have been rearranged into subroutine, to try to cure the mess that was before (see Section 1.2 of the README file )

What was New in Version 1.01

The option "autoPackets" was added in order to allow the number of energy packets to be used in the next iteration to automatically increase in the case of a convergence plateau being reached. Please see the README file, for more info.

Get MOCASSIN

Source Code

Email me for a copy of MOCASSIN (Version 2.01). (be@star.ucl.ac.uk)

Documentation

The bare necessities to run MOCASSIN are all summarised in the README file, which is quite concise and it is really worth reading before attempting anything. The other sources contain more in-depth info about the code itself (particularly the Thesis file).

README Thesis Ercolano et al., 2003 Ercolano et al., 2005 (coming soon)

MOCASSIN updates

If you would like to receive (very sporadic) updates about MOCASSIN, including new versions and patches to old versions, please send me an email (be@star.ucl.ac.uk) and I will add you to my mailing list.