The Flash Center is pleased to announce the release of the
next version of the FLASH code, version 3.1. FLASH 3.1 resolves 
several issues reported/requested by early users of FLASH3.0, 
including performance, features and bugs. 

Capabilities added since the FLASH3.0 release include:

* Support for Paramesh 4.0, which includes operation of Paramesh in 
  library mode.
 
* Major performance improvement in the Particles data movement algorithm
  released with 3.0, and a new Particles data movement algorithm which is
  more efficient in some situations.

* Support for multiple particle types in a single simulation. This feature
  has had limited testing.

* An algorithm to map a Paramesh grid to an uniform grid which, when coupled
  with the multigrid solver, permits the coarse grid exact solve at 
  higher resolution in parallel. This feature could significantly improve the
  scalability of the multigrid solver.

* Enhancement in the IO unit to permit splitting of a single checkpoint
  or plotfile. This feature in included to enable scalability of parallel
  file write on hundreds of thousands of processors.

* Fully supported implementations of Ionize, Conductivity and Diffusion.

* Reorganization of the Hydro and Driver units to better reflect their
  functionality in relation to the code architecture.

* Logfile unit is enhanced to allow any processor in the simulation to
  be able to create and write into a private logfile. This feature is
  useful in gathering extra information from single/few processor
  failures when those failures do not occur on the master processor.
  
The release is available at:

http://flash.uchicago.edu/website/download/

A stripped down version of FLASH3 that may be downloaded without a
license is also available at the same location. This version is
essentially the FLASH framework without any implementations.
Flash Center is also providing support for "add-ons" to the
code. Please see the section on "What's new in this release" in the
first chapter of the user's guide for details.

Additionally, the FLASH testing software FlashTest, which became
available with the alpha release, continues to be available for
download at:

http://flash.uchicago.edu/website/codesupport/

Many, but not all parts of FLASH3 are backwards-compatible with
FLASH2.  The Flash code group has written extensive documentation
detailing how to make the transition from FLASH2 to FLASH3 as smooth
as possible.  The user should look to:

http://flash.uchicago.edu/website/codesupport/

The website also contains other documentation including
a user's guide and a developer's section.  A new feature in FLASH3
documentation is the online description of the public interface
routines to various code units.


FLASH should be portable to most UNIX-like operating systems with a 
Python interpreter, Fortran 90 compiler, C compiler and MPI library. 
It has been used in production mode, or undergone regular testing on            
the following platforms. 

 
-- IBM BlueGene and Power5

   compilers : FORTRAN90 : xlf90

               C         : xlc

-- CRAY-XT4 system

   compilers : FORTRAN90 : Portland Group Fortran 90

               C         : gcc

-- Linux

   compilers: FORTRAN90 : Portland Group Fortran 90
                     
                          Lahey/Fujitsu Fortran 95 

                          Intel Fortran Compiler
    
                          gFortran (known to have trouble with versions
                              before 4.1.0)

                          NAGWare Fortran 95

                          Absoft 
   
              C         : gcc

                          Portland Group C Compiler
 
                          Intel C++ Compiler       
 
-- MAC-OSX

   compilers : FORTRAN90 : xlf, gFortran

               C         : gcc


-- IRIX 6.5

   compilers: MIPSpro 

FLASH uses libraries such as MPI for communication, Paramesh
for AMR, and HDF5 or PnetCDF for IO. The source for Paramesh is
included in the distribution; the version included in this release is
equivalent to Paramesh 4.0. Some earlier versions of HDF5, for example
1.6.1, have been known to have issues with FLASH. We recommend using
version 1.6.2 or higher of the HDF5 library. 

Two options are available to visualize FLASH output data. One is 
Fidlr, the IDL based visualization tool included in the
distribution. Fidlr requires IDL version 6.1 or higher to work correctly.  
A more extensive option is VisIt, a visualization tool from LLNL, 
available from  

http://flash.uchicago.edu/website/codesupport/visit, and
https://wci.llnl.gov/codes/visit

Visit supports FLASH data output Format. To use the current released
version of Visit with the FLASH file format version 9 (the 3.0 release
version) users will need a patch which is also available from  

http://flash.uchicago.edu/website/codesupport/visit

Development of the FLASH Code was funded by the DOE-supported
ASC/Alliance Center for Astrophysical Thermonuclear Flashes.  We
acknowledge support received from Lawrence Livermore National
Laboratory and the University of Chicago.

All publications resulting from the use of the FLASH Code must
acknowledge the ASC/Alliance Center for Astrophysical Thermonuclear
Flashes.  Addition of the following text to the paper acknowledgments
will be sufficient.

         "The software used in this work was in part developed by the
         DOE-supported ASC/Alliance Center for Astrophysical Thermonuclear
         Flashes at the University of Chicago."

