forked from lijiext/lammps
32 lines
959 B
Python
32 lines
959 B
Python
from nbody_graph_search import Ugraph
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# To find 2-body "bond" interactions, we would use this subgraph:
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#
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#
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# *---* => one bond connects atoms 0 and 1
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# 0 1
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#
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bond_pattern = Ugraph([(0,1)])
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# (Ugraph atom indices begin at 0, not 1)
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# The next function eliminates the redundancy between 0-1 and 1-0:
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def canonical_order(match):
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"""
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It does not make sense to define a separate bond between atoms 1 and 2,
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and between atoms 2 and 1. This function will swap the atoms in the bond
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if the first atom > second atom.
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"""
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# match[0][0:2] contains the ID numbers for the 2 atoms in the match
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atom0 = match[0][0]
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atom1 = match[0][1]
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# match[1][0:1] contains the ID numbers for the 1 bond
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bond0 = match[1][0]
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if atom0 < atom1:
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#return ((atom0, atom1), (bond0)) same thing as:
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return match
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else:
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return ((atom1, atom0), (bond0))
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