explicit BeginEnd(Collection _collection, const TransformT& _transform = TransformT() ): b(_collection.begin()), e(_collection.end()), transform(_transform) {}
void TransformT( CompoundParticle & particle ){ for ( size_t iPart=0; iPart<particle.m_uiNumConstituents; ++iPart ){ TransformT( particle.m_apConstituents[ iPart ] ); } }