[Carpet] Significant Changes to Development Version

[Erik Schnetter]

We have improved the development version of Carpet significantly.   
These improvements make it possible to perform larger simulations, and  
they reduce the likelihood of errors.  The particular improvements  
concern the following:

The data structures and algorithms storing and handling the  
communication schedule are much more efficient on large numbers  
(several hundred or more) processors.  This makes Carpet scale to more  
than 8,000 cores.

The interface for defining and making dynamic changes to grid  
hierarchies is simpler, and buffer zones are handled in a cleaner  
manner.  This makes it easier to write user code which defines or  
updates the grid hierarchy, and reduces the chance of inconsistencies  
therein.

During checkpointing and recovery, the grid structure is saved and  
restored by default.  This avoids accidental changes upon recovery.

The efficiency of I/O has been increased, especially for HDF5 based  
binary I/O.  It is possible to combine several variables into one file  
to reduce the number of output files.

A new thorn LoopControl offers iterators over grid points, implemented  
as C-style macros.  These iterators allow additional important loop- 
level optimisations, such as loop tiling or OpenMP parallelisation.   
Efficient cache handling and hybrid communication models have a large  
potential for performance improvements on current and future  
architectures.



More details can be found on <http://www.carpetcode.org/>.  Special  
thanks go to the CCT and AEI numerical relativity groups and the XiRel  
collaboration <http://www.cactuscode.org/Development/xirel>.

It is in the nature of a development version to sometimes contain  
significant errors while significant progress is made.  Please be  
careful, and help correct any errors you detect.

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/

My email is as private as my paper mail.  I therefore support encrypting
and signing email messages.  Get my PGP key from www.keyserver.net.



-------------- next part --------------
A non-text attachment was scrubbed...
Name: PGP.sig
Type: application/pgp-signature
Size: 194 bytes
Desc: This is a digitally signed message part
Url : /archives/developers/attachments/20080301/7bd29abf/attachment.pgp