[Developers] ADMMacros, syntax errors in C version

[Erik Schnetter]

On Jul 4, 2007, at 09:48:31, Frank Löffler wrote:

> Hi,
>
> this patch fixes two missing ";" in the C version.

Frank,

thanks for the correction.  I have applied your patch.

The fact that this code did not compile before indicates that the C  
version of the macros has not yet been thoroughly tested.  You should  
be very careful if you want to use it.  Historically, only the  
Fortran version has of ADMMacros been used.

The code in ADMMacros is hand-written and therefore tends to contain  
errors.  These days, many people autogenerate code using a variety of  
systems based on Maple or Mathematica; I'm sure you know Kranc  
<http://numrel.aei.mpg.de/Research/Kranc/>, and there are other,  
similar systems.  We (the LSU group) recently implemented our  
harmonic formulation of the Einstein equations using Maple directly.

Generating code automatically also has certain other advantages.  For  
example, one can perform high-level optimisations of the code  
depending on the machine for which one generates code.  This may  
become important in the future as machines have more processors  
(cores) and/or less memory per node.  With hand-written code these  
optimisations need to be applied manually, while a code-generation  
system can generate the corresponding optimisations automatically.

If one wanted e.g. to use or to experiment with multi-threading or  
OpenMP, which can potentially save a significant amount of memory,  
one would have to change only a few lines of Kranc to generate the  
corresponding directives.  This will allow much faster experiments  
than manually annotating all existing loops in a production code,  
probably protected by #ifdef statements to be able to switch forth  
and back.

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>

My email is as private as my paper mail.  I therefore support encrypting
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