Updated hash algorithm to use json instead of repr.

ionize/Ion/BaseIon.py

@@ -2,6 +2,7 @@
 import numpy as np
 import contextlib
 from math import sqrt
+import json
 
 from .fixed_state import fixed_state
 from ..Solvent import Aqueous
@@ -33,7 +34,7 @@ class BaseIon(object):
     def __repr__(self):
         """Return an unambiguous string representation."""
         inner = []
-        for prop in self._state:
+        for prop in sorted(self._state):
             prop = str(prop)  # convert unicode to string
             value = getattr(self, prop)
             if isinstance(value, np.ndarray):
@@ -49,7 +50,7 @@ def __str__(self):
 
     def __hash__(self):
         """Return the hash value for the object."""
-        return hash(repr(self))
+        return hash(json.dumps(self._state))
 
     def __eq__(self, other):
         """Test equality between two ions."""

ionize/Solvent.py

@@ -62,7 +62,6 @@ def dissociation(self, ionic_strength, temperature):
     def debye(self, ionic_strength, temperature):
         """Return the Debye length of the solvent."""
         dielectric = self.dielectric(temperature)
-        viscosity = self.viscosity(temperature)
         lamda = (dielectric * permittivity * boltzmann * kelvin(temperature) /
                  elementary_charge**2. /
                  (ionic_strength * lpm3) / avogadro) ** .5
@@ -144,7 +143,7 @@ def dielectric(self, temperature):
     def viscosity(self, temperature):
         """Return the viscosity of water at the specified temperature.
 
-        Correlation is based on Fox and McDonald's Intro to FLuid Mechanics.
+        Correlation is based on Fox and McDonald's Intro to Fluid Mechanics.
         """
         temperature = kelvin(temperature)
         viscosity_ = 2.414e-5 * 10**(247.8 / (temperature - 140))