class SelectBranch : public feasst::TrialSelectAngle
A random particle of given type is selected if previously perturbed sites are not available. Select two mobile sites bonded to anchor 1, that also forms a third angle with anchor 2.
Thus, the bonded topology appears as:
::In the source code, these are often shortened as anchor1->a1, mobile2->m2, etc.
anchor2 | anchor1 / \ mobile1 mobile2