nbody_Bonds.py
No OneTemporary
Actions

Subscribers

None

File Metadata

	from nbody_graph_search import Ugraph

	# To find 2-body "bond" interactions, we would use this subgraph:
	#
	#
	# --- => one bond connects atoms 0 and 1
	# 0 1
	#

	bond_pattern = Ugraph([(0,1)])
	# (Ugraph atom indices begin at 0, not 1)


	# The next function eliminates the redundancy between 0-1 and 1-0:
	def canonical_order(match):
	"""
	It does not make sense to define a separate bond between atoms 1 and 2,
	and between atoms 2 and 1. This function will swap the atoms in the bond
	if the first atom > second atom.

	"""
	# match[0][0:2] contains the ID numbers for the 2 atoms in the match
	atom0 = match[0][0]
	atom1 = match[0][1]
	# match[1][0:1] contains the ID numbers for the 1 bond
	bond0 = match[1][0]
	if atom0 < atom1:
	#return ((atom0, atom1), (bond0)) same thing as:
	return match
	else:
	return ((atom1, atom0), (bond0))