Dear IMP-users,

I have a question regarding the IMP.em.EnvelopeFitRestraint class: As a simple test I just tried to evaluate this restraint with an EM density map and a set of particles corresponding to each subunits that fill the map. As coordinates for each particle, I have assigned a random vector belonging to the boundingbox of the density map. Depending on the coordinates of the particles, sometimes the restraint is correctly calculated, sometimes I get the following error message:

File "/usr/local/lib/IMP-python/IMP/kernel/__init__.py", line 2183, in evaluate return _IMP_kernel.Restraint_evaluate(self, *args) _IMP_base.UsageException: Usage check failure: The point is not part of the grid Context: fit_restraint::evaluate/fit_restraint scoring::evaluate/fit_restraint scoring::do_add_score_and_derivatives/fit_restraint::add_score_and_derivatives/fit_restraint::do_add_score_and_derivatives

Can somebody explain me this error?

Thank you

Karine