core/cover_particles.py

Show how to maintain a sphere per residue which includes all atoms of the residue. The derivatives are propagated from the sphere cover to the atoms so that restraints can be used at multiple levels.

## \example core/cover_particles.py
# Show how to maintain a sphere per residue which includes all atoms
# of the residue. The derivatives are propagated from the sphere
# cover to the atoms so that restraints can be used at multiple
# levels.

import IMP
import IMP.core
import IMP.atom
import sys

IMP.setup_from_argv(sys.argv, "cover particles")

m = IMP.Model()
prot = IMP.atom.read_pdb(IMP.core.get_example_path('example_protein.pdb'), m)
res = IMP.atom.get_by_type(prot, IMP.atom.RESIDUE_TYPE)
pr = IMP.core.ChildrenRefiner(IMP.atom.Hierarchy.get_traits())
for r in res:
    # add coordinates and a radius to the residue particle
    IMP.core.XYZR.setup_particle(r)
    # make sure that the coordinates and the radius define a sphere
    # which contains all of the leaves (atoms) of the residue
    IMP.core.Cover.setup_particle(r.get_particle(), pr)
# update the coordinates of the residue particles so that they cover the atoms
m.update()