def test_dimensionless_units():
assert utils.string_to_unit('dimensionless') == unit.dimensionless
unit_string = utils.unit_to_string(unit.dimensionless)
unit_value = utils.string_to_unit(unit_string)
assert unit_value == unit.dimensionless
def pint_unit_to_openmm(pint_unit):
"""Converts a `pint.Unit` to a `simtk.unit.Unit`.
Notes
-----
Not all pint units are available in OpenMM.
Parameters
----------
pint_unit: pint.Unit
The unit to convert.
Returns
-------
simtk.unit.Unit
The converted unit.
"""
from openforcefield.utils import string_to_unit
if pint_unit is None or isinstance(pint_unit, UndefinedAttribute):
return None
assert isinstance(pint_unit, pint.Unit)
pint_unit_string = f"{pint_unit:!s}"
# Handle a unit name change in pint 0.10.*
pint_unit_string = pint_unit_string.replace("standard_atmosphere",
"atmosphere")
try:
# noinspection PyTypeChecker
openmm_unit = string_to_unit(pint_unit_string)
except AttributeError:
logger.info(
f"The {pint_unit_string} pint unit string (based on the {pint_unit} object) "
f"could not be understood by `openforcefield.utils.string_to_unit`"
)
raise
return openmm_unit
def pint_unit_to_openmm(pint_unit):
"""Converts a `pint.Unit` to a `simtk.unit.Unit`.
Notes
-----
Not all pint units are available in OpenMM.
Parameters
----------
pint_unit: pint.Unit
The unit to convert.
Returns
-------
simtk.unit.Unit
The converted unit.
"""
from openforcefield.utils import string_to_unit
if pint_unit is None:
return None
assert isinstance(pint_unit, unit.Unit)
pint_unit_string = str(pint_unit)
try:
# noinspection PyTypeChecker
openmm_unit = string_to_unit(pint_unit_string)
except AttributeError:
logging.info(
f'The {pint_unit_string} pint unit string (based on the {pint_unit} object) '
f'could not be understood by `openforcefield.utils.string_to_unit`'
)
raise
return openmm_unit