strip_unit¶

Strips the unit from an openmm.unit.Quantity or pint.Quantity object.

Parameters:

valuenumbers.Number, openmm.unit.Quantity, or pint.Quantity: Physical quantity for which to get the magnitude of in the unit specified in unit_.
unit_str, openmm.unit.Unit, or pint.Unit, optional: Unit to convert to. If not specified, the original unit is used.

Returns:

valuenumbers.Number: Magnitude of the physical quantity in the specified unit.
unit_openmm.unit.Unit or pint.Unit: Unit of the physical quantity.

Examples

For any quantity other than a openmm.unit.Quantity or pint.Quantity object, the raw quantity and user-specified unit are returned.

>>> strip_unit(90.0, "deg")
(90.0, 'deg')
>>> strip_unit(90.0, ureg.degree)
(90.0, <Unit('degree')>)

If no target unit is specified, the magnitude and original unit of the quantity are returned.

>>> strip_unit(1.380649e-23 * ureg.joule * ureg.kelvin ** -1)
(1.380649e-23, <Unit('joule / kelvin')>)

If a target unit using the same module as the quantity is specified, the quantity is first converted to the target unit, if necessary, before its magnitude and unit are returned.

>>> g = 9.80665 * ureg.meter / ureg.second ** 2
>>> strip_unit(g, "meter/second**2")
(9.80665, <Unit('meter / second ** 2')>)
>>> strip_unit(g, ureg.foot / ureg.second ** 2)
(32.17404855643044, <Unit('foot / second ** 2')>)

If a target unit using a different module than the quantity is specified, the quantity is converted to the specified target unit in the new module, if necessary, before its magnitude and unit are returned.

>>> strip_unit(8.205736608095969e-05 * unit.meter ** 3 * unit.atmosphere
...            / (unit.kelvin * unit.mole),
...            ureg.joule / (ureg.kelvin * ureg.mole))
(8.31446261815324, <Unit('joule / kelvin / mole')>)
>>> strip_unit(8.205736608095969e-05 * ureg.meter ** 3 * ureg.atmosphere
...            / (ureg.kelvin * ureg.mole),
...            unit.joule / (unit.kelvin * unit.mole))
(8.31446261815324, Unit({BaseUnit(..., name="kelvin", ...): -1.0, ...}))