units_example

The units model is taken from the pymatgen code and modified to contain more unit conversions for the STREAMM code.

from pprint import pprint

import pymatgen_core.core.units as units

Each object in streamm has a property _unit_conf that specifies the units for the object.

The default unit_conf is in units

pprint(units.unit_conf)

The units of most objects in streamm can be changed using an update_units function associated with that object

The units are then converted using a units_instance

For example to convert units of length

Unit_instance = units.partial(units.FloatWithUnit, unit_type='length')

value = 10.0
old_unit = 'ang'
new_unit = 'nm'
print("Conversion of {} to {} is {}".format(old_unit,new_unit,Unit_instance(value,old_unit).to(new_unit)))

value = 10.0
old_unit = 'mile'
new_unit = 'ang'
print("Conversion of {} to {} is {}".format(old_unit,new_unit,Unit_instance(value,old_unit).to(new_unit)))

To convert units of energy

Unit_instance = units.partial(units.FloatWithUnit, unit_type='energy')

value = 37.500000
old_unit = 'kCalmol'
new_unit = 'kJmol'
print("Conversion of {} {} to {} is {}".format(value,old_unit,new_unit,Unit_instance(value,old_unit).to(new_unit)))

value = 1.0
old_unit = 'eV'
for new_unit in ['Ha','J','wavenumber','kJmol','kCalmol']:
    print("Conversion of {} {} to {} is {}".format(value,old_unit,new_unit,Unit_instance(value,old_unit).to(new_unit)))

We have special units for bond stretching of energy/length^2

Unit_instance = units.partial(units.FloatWithUnit, unit_type='harm_bond_coeff')

value = 367.000000
old_unit = 'kCalmolsqang'
new_unit = 'kJmolsqnm'
print("Conversion of {} {} to {} is {}".format(value,old_unit,new_unit,Unit_instance(value,old_unit).to(new_unit)))