[gmx-developers] Using C++ with Gromacs
lindahl at cbr.su.se
Thu May 8 09:07:48 CEST 2008
On May 8, 2008, at 2:40 AM, Julie Bernauer wrote:
> I am not sure it is a real suitable example but one could maybe cite
> Boost libraries and Boost.python. (CGAL is ported to python with
> Boost uses bjam though.
On May 8, 2008, at 2:53 AM, Peter Eastman wrote:
> The ones that immediately spring to mind for me are Open Dynamics
> Engine and Crystal Space 3D. Naturally, this depends on what you
> mean by "portable". OpenMM will only really be useful if you have a
> recent NVidia or ATI GPU and are using an OS and compiler that
> supports the appropriate programming environment (CUDA or Brook+).
> So we only have a narrow range of configurations we're concerned
> about supporting in the near term.
I'm sure all those libraries are great examples of C++ design, but as
Peter said I think it comes down to very different views on
"portability". Nothing wrong with that (we have different target
audiences), but for Gromacs portability means we compile out-of-the-
box using combinations like portland compilers and UNICOS (Cray XT4),
5-year-old versions of IBM XLC on AIX (since that might be compiler
your local supercomputing center has a supported MPI version for),
IRIX, HP aC on Itanium, whatever special BLAS/LAPACK libraries the
vendor provides, etc.
Compared to that it's a walk in the park to achieve portability
between the two most recent versions of gcc & Visual C++ on Linux/OSX/
Windows, which seems to be the reference for a couple of the above
However, this does _not_ mean we shouldn't do much more object
oriented interfaces and data abstraction in Gromacs (we're working on
that, but there's a lot of old code to clean up), it's just that we'll
need to accomplish it with handles rather than formal classes, and
forego some of the more advanced c++ stuff.
Still, I couldn't help to notice this in the documentation of Open
"The ODE library is written in C++, but its public interface is made
of simple C functions, not classes. Why is this?
• Using a C interface only is simpler - the features of C++ features
do not help much for ODE.
• It prevents C++ mangling and runtime-support problems across
• The user doesn't have to be familiar with C++ quirks to use ODE.
More information about the gromacs.org_gmx-developers