/
_solution.py
149 lines (120 loc) · 5.55 KB
/
_solution.py
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# -*- coding: utf-8 -*-
"""
"Sandbox" module for exploring API useful for digital labbooks.
Examples
--------
>>> from chempy.units import to_unitless, default_units as u
>>> s1 = Solution(0.1*u.dm3, {'CH3OH': 0.1 * u.molar})
>>> s2 = Solution(0.3*u.dm3, {'CH3OH': 0.4 * u.molar, 'Na+': 2e-3*u.molar, 'Cl-': 2e-3*u.molar})
>>> s3 = s1 + s2
>>> abs(to_unitless(s3.volume - 4e-4 * u.m**3, u.dm3)) < 1e-15
True
>>> s3.concentrations.isclose({'CH3OH': 0.325*u.molar, 'Na+': 1.5e-3*u.molar, 'Cl-': 1.5e-3*u.molar})
True
>>> s4 = s3.dissolve({'CH3OH': 1*u.gram})
>>> abs(s4.concentrations['CH3OH'] - (0.325 + 1/(12.011 + 4*1.008 + 15.999)/.4)*u.molar) < 1e-4
True
"""
from __future__ import (absolute_import, division, print_function)
import copy
from .chemistry import Substance
from .units import (
get_derived_unit, html_of_unit, is_unitless, SI_base_registry,
to_unitless, rescale, default_units as u
)
from .util.arithmeticdict import ArithmeticDict, _imul, _itruediv
from .printing import as_per_substance_html_table
class QuantityDict(ArithmeticDict):
def __init__(self, units, *args, **kwargs):
self.units = units
super(QuantityDict, self).__init__(lambda: 0*self.units, *args, **kwargs)
self._check()
@classmethod
def of_quantity(cls, quantity_name, *args, **kwargs):
instance = cls(get_derived_unit(SI_base_registry, quantity_name), *args, **kwargs)
instance.quantity_name = quantity_name
return instance
def rescale(self, new_units):
return self.__class__(new_units, {k: rescale(v, new_units) for k, v in self.items()})
def _repr_html_(self):
if hasattr(self, 'quantity_name'):
header = self.quantity_name.capitalize() + ' / '
else:
header = ''
header += html_of_unit(self.units)
tab = as_per_substance_html_table(to_unitless(self, self.units), header=header)
return tab._repr_html_()
def _check(self):
for k, v in self.items():
if not is_unitless(v/self.units):
raise ValueError("entry for %s (%s) is not compatible with %s" % (k, v, self.units))
def __setitem__(self, key, value):
if not is_unitless(value/self.units):
raise ValueError("entry for %s (%s) is not compatible with %s" % (key, value, self.units))
super(QuantityDict, self).__setitem__(key, value)
def copy(self):
return self.__class__(self.units, copy.deepcopy(list(self.items())))
def __repr__(self):
return "{}({}, {})".format(self.__class__.__name__,
repr(self.units),
dict(self))
def __mul__(self, other):
d = dict(copy.deepcopy(list(self.items())))
_imul(d, other)
return self.__class__(self.units * getattr(other, 'units', 1), d)
def __truediv__(self, other):
d = dict(copy.deepcopy(list(self.items())))
_itruediv(d, other)
return self.__class__(self.units / getattr(other, 'units', 1), d)
def __floordiv__(self, other):
a = self.copy()
if getattr(other, 'units', 1) != 1:
raise ValueError("Floor division with quantities not defined")
a //= other
return a
def __rtruediv__(self, other):
""" other / self """
return self.__class__(getattr(other, 'units', 1)/self.units,
{k: other/v for k, v in self.items()})
def __rfloordiv__(self, other):
""" other // self """
return self.__class__(getattr(other, 'units', 1)/self.units,
{k: other//v for k, v in self.items()})
class AutoRegisteringSubstanceDict(object):
def __init__(self, factory=Substance.from_formula):
self.factory = factory
self._store = {}
def __getitem__(self, key):
if key not in self._store:
self._store[key] = self.factory(key)
return self._store[key]
class Solution(object):
def __init__(self, volume, concentrations, substances=None, solvent=None):
if not is_unitless(volume/u.dm3):
raise ValueError("volume need to have a unit (e.g. dm3)")
self.volume = volume
self.concentrations = QuantityDict(u.molar, concentrations)
if substances is None:
substances = AutoRegisteringSubstanceDict()
self.substances = substances
self.solvent = solvent
def __eq__(self, other):
if not isinstance(other, Solution):
return NotImplemented
return all([getattr(self, k) == getattr(other, k) for k in 'volume concentrations substances solvent'.split()])
def __add__(self, other):
if self.solvent != other.solvent:
raise NotImplementedError("Mixed solvent should be represented as concentrations")
tot_amount = self.concentrations*self.volume + other.concentrations*other.volume
tot_vol = self.volume + other.volume
return Solution(tot_vol, tot_amount / tot_vol, self.substances, self.solvent)
def dissolve(self, masses):
contrib = QuantityDict(u.molar, {k: v/self.substances[k].molar_mass()/self.volume for k, v in masses.items()})
return Solution(self.volume, self.concentrations + contrib, self.substances, self.solvent)
def withdraw(self, volume):
if volume > self.volume:
raise ValueError("Cannot withdraw a volume greater than the solution volume")
if volume < volume*0:
raise ValueError("Cannot withdraw a negative volume")
self.volume -= volume
return Solution(volume, self.concentrations, self.substances, self.solvent)