error in CloseBipartitePairContainer when including pairs on same rigid body

[jtempkin]

I ran into some strange behavior in CloseBipartitePairContainer when it includes pairs that are both contained in a single rigid body. When one tries to do this, the container only includes pairs formed between members of the first list and completely excludes any members from the second.

Here is a short script reproducing the error:

import IMP
import IMP.core
import IMP.atom


m = IMP.Model()

molA = IMP.atom.Molecule.setup_particle(m, IMP.Particle(m))
molB = IMP.atom.Molecule.setup_particle(m, IMP.Particle(m))

mols = [molA, molB]

for i, mol in enumerate(mols):

    p1 = IMP.core.XYZR.setup_particle(IMP.Particle(m))
    p2 = IMP.core.XYZR.setup_particle(IMP.Particle(m))

    p1.set_coordinates(IMP.algebra.Vector3D(i, i + 1, 0.0))
    p2.set_coordinates(IMP.algebra.Vector3D(i + 1, i + 1, 0.0))
    p1.set_radius(1.0)
    p2.set_radius(1.0)
    d1 = IMP.atom.Mass.setup_particle(m, p1, 1.0)
    d2 = IMP.atom.Mass.setup_particle(m, p2, 1.0)

    mol.add_child(d1)
    mol.add_child(d2)


rigid_mols = [IMP.atom.create_rigid_body(mol) for mol in mols]

list0 = [mol.get_child(0) for mol in mols]
list1 = [mol.get_child(1) for mol in mols]

lsc0 = IMP.container.ListSingletonContainer(m, list0)
lsc1 = IMP.container.ListSingletonContainer(m, list1)
bcp = IMP.container.CloseBipartitePairContainer(lsc0, lsc1, 5.0)

m.update()

print("Mol A:\n", lsc0.get_contents())
print("Mol B:\n", lsc1.get_contents())
print("Bipartitle container pairs:", bcp.get_contents())