misc. optimizations; add lru_cache to more places

src/pyEQL/engines.py

@@ -672,15 +672,20 @@ def get_activity_coefficient(self, solution, solute):
 
         # translate the species into keys that phreeqc will understand
         k = standardize_formula(solute)
-        el = k.split("[")[0]
-        chg = k.split("[")[1].split("]")[0]
+        spl = k.split("[")
+        el = spl[0]
+        chg = spl[1].split("]")[0]
         if chg[-1] == "1":
             chg = chg[0]  # just pass + or -, not +1 / -1
         k = el + chg
 
         # calculate the molal scale activity coefficient
-        print(k)
-        act = ppsol.activity(k, "mol") / ppsol.molality(k, "mol")
+        try:
+            act = ppsol.activity(k, "mol") / ppsol.molality(k, "mol")
+        except ZeroDivisionError:
+            # assume this means the solute does not exist
+            logger.warning(f"Solute {solute} not found in solution. returning 0 activity")
+            act = 0
 
         # remove the PPSol from the phreeqcpython instance
         self._destroy_ppsol(ppsol)

src/pyEQL/solution.py

@@ -108,8 +108,11 @@ def __init__(
         # create a logger attached to this class
         # self.logger = logging.getLogger(type(self).__name__)
 
-        # per-instance cache of get_property calls
-        self.get_property = lru_cache(maxsize=None)(self._get_property)
+        # per-instance cache of get_property and other calls that do not depend
+        # on composition
+        # see https://rednafi.com/python/lru_cache_on_methods/
+        self.get_property = lru_cache()(self._get_property)
+        self.get_molar_conductivity = lru_cache()(self._get_molar_conductivity)
 
         # initialize the volume recalculation flag
         self.volume_update_required = False
@@ -342,6 +345,10 @@ def temperature(self, temperature: str):
         # recalculate the volume
         self.volume_update_required = True
 
+        # clear any cached solute properties that may depend on temperature
+        self.get_property.cache_clear()
+        self.get_molar_conductivity.cache_clear()
+
     @property
     def pressure(self) -> Quantity:
         """Return the hydrostatic pressure of the solution in atm."""
@@ -584,14 +591,16 @@ def viscosity_kinematic(self) -> Quantity:
             a1 = ureg.Quantity(params["a1"]["value"]).magnitude
             b0 = ureg.Quantity(params["b0"]["value"]).magnitude
             b1 = ureg.Quantity(params["b1"]["value"]).magnitude
+
+            # compute the delta G parameters
+            temperature = self.temperature.to("degC").magnitude
+            G_123 = a0 + a1 * (temperature) ** 0.75
+            G_23 = b0 + b1 * (temperature) ** 0.5
         else:
+            # TODO - fall back to the Jones-Dole model! There are currently no eyring parameters in the database!
             # proceed with the coefficients equal to zero and log a warning
-            logger.warning("Viscosity coefficients for %s not found. Viscosity will be approximate." % salt.formula)
-
-        # compute the delta G parameters
-        temperature = self.temperature.to("degC").magnitude
-        G_123 = a0 + a1 * (temperature) ** 0.75
-        G_23 = b0 + b1 * (temperature) ** 0.5
+            logger.info("Viscosity coefficients for %s not found. Viscosity will be approximate." % salt.formula)
+            G_123 = G_23 = 0
 
         # get the kinematic viscosity of water, returned by IAPWS in m2/s
         nu_w = self.water_substance.nu
@@ -848,7 +857,6 @@ def total_dissolved_solids(self) -> Quantity:
                 continue
             tds += self.get_amount(s, "mg/L")
 
-        # return tds + self.start_uncharged_TDS
         return tds
 
     @property
@@ -885,7 +893,7 @@ def debye_length(self) -> Quantity:
 
         """
         # to preserve dimensionality, convert the ionic strength into mol/L units
-        ionic_strength = self.ionic_strength.magnitude * ureg.Quantity("mol/L")
+        ionic_strength = ureg.Quantity(self.ionic_strength.magnitude, "mol/L")
         dielectric_constant = self.dielectric_constant
 
         debye_length = (
@@ -2204,7 +2212,7 @@ def get_transport_number(self, solute, activity_correction=False) -> Quantity:
 
         return (numerator / denominator).to("dimensionless")
 
-    def get_molar_conductivity(self, solute: str) -> Quantity:
+    def _get_molar_conductivity(self, solute: str) -> Quantity:
         """
         Calculate the molar (equivalent) conductivity for a solute.
 

src/pyEQL/utils.py

@@ -7,10 +7,12 @@
 """
 
 from collections import UserDict
+from functools import lru_cache
 
 from pymatgen.core.ion import Ion
 
 
+@lru_cache
 def standardize_formula(formula: str):
     """
     Convert a chemical formula into standard form.