Problem 356

Dear Richard,
as Makoto Asai pointed out in a previous reply to your enquiry, a patch
correcting a problem found in Geant4 4.0 has been released, which speeds up the
execution significantly. The problem was a general one, so I suggest you to
verify whether with the released patch also your application improves its
performance. I'd appreciate if you'd let us know whether any significant problem
persists, even with the correction patch.
Other possible sources of performance degradation in the last release have been
investigated, and any further improvements, if achievable, would be available in
next patches or release.
As to lowenergy electromagnetic physics, we have in progress a major design
iteration in the package, as well as physics extensions, that started last
summer and will presumably continue for the whole 2002. Since this evolution is
carried on through an iterative and incremental process, there may be occasional
performance degradations (usually corresponding to the introduction of new
functionalities), but we try to compensate them, whenever possible, with a
following cycle devoted to performance optimization.
We appreciate the patience of the package users, while this design iteration is
in progress: we do our best to accomodate the needs of users requiring new
or improved functionalities, as well as of those needing good performance, but,
with the available resources in the group, sometimes we are obliged to split the
extension and optimization cycles into two Geant4 public releases.

Best wishes,
Maria Grazia

Dear Richard,
thanks for your feedback. We are investigating the performance of the Low Energy
electromagnetic package specifically. By the way, two students of mine, working
on a similar brachytherapy application, did not experience any major performance
degradation with the latest Geant4 reference tag. We'll keep you up to date with
any progress.

Best wishes,
Maria Grazia

The estimate to address this problem report takes approximetely four years' work
to set up a testing and validation process in support of a performance
improvement process. The Geant4 spokesman asked me to close this problem.
Unfortunately, at the present time the closest response available in the problem
report menu is "WONTFIX".
In the meantime, however, many papers have been published based on Geant4 Low
Energy Electromagnetic package, in spite of the poor performance mentioned in
this problem report. We assume, therefore, that the poor performance does not
prevent the usage of the package in a large number of use cases.