small stats fix (no functionality change)

[brookehus]

Development:

• [x] Implement feature / fix bug
• [x] Add documentation

• [ ] Add tests

  Checks:

• [x] Run nosetests
• [ ] Check pep8 compliance

I was debugging some scripts I have and ran into issues (1) understanding my own logic in feature/statistics and (2) having something weird happen with some hidden attributes. I've added a deepcopy to solve this, which replaces former line 164:

self.bond_pairs = self._adj_backbone_pairs

with new line 176:

self.bond_pairs = copy.deepcopy(self._adj_backbone_pairs).

Besides that and import copy, the only other changes are some more documentation.

[nec4]

Will review tonight!

[brookehus]

Yeah. If instead of a deep copy I use the previous

self.bond_pairs = self._adj_backbone_pairs

then this is a reference, not a new list. Then, when I extend self.bond_pairs later, in the old version self._adj_backbone_pairs also gets extended. I was trying to debug something and wanted to check if all the adjacent backbone pairs were correctly calculated, but the hidden attribute was getting my custom pairs too because of the lack of deep copy.

[nec4]

Gotcha - nice catch! LGTM