parmed.unit.baseunit module

Module simtk.unit.baseunit

Contains BaseUnit class, which is a component of the Unit class.

This is part of the OpenMM molecular simulation toolkit originating from Simbios, the NIH National Center for Physics-Based Simulation of Biological Structures at Stanford, funded under the NIH Roadmap for Medical Research, grant U54 GM072970. See https://simtk.org.

Portions copyright (c) 2012 Stanford University and the Authors. Authors: Christopher M. Bruns Contributors: Peter Eastman

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

class parmed.unit.baseunit.BaseUnit(base_dim, name, symbol)

Bases: object

Physical unit expressed in exactly one BaseDimension.

For example, meter_base_unit could be a BaseUnit for the length dimension. The BaseUnit class is used internally in the more general Unit class.

Methods

conversion_factor_to(other)	Returns a conversion factor from this BaseUnit to another BaseUnit.
define_conversion_factor_to(other, factor)	Defines a conversion factor between two BaseUnits.
get_dimension_tuple()	Returns a sorted tuple of (BaseDimension, exponent) pairs, that can be used as a dictionary key.
iter_base_dimensions()	Returns a dictionary of BaseDimension:exponent pairs, describing the dimension of this unit.

iter_base_units

conversion_factor_to(other)

Returns a conversion factor from this BaseUnit to another BaseUnit.

It does not matter which existing BaseUnit you define the conversion factor to. Conversions for all other known BaseUnits will be computed at the same time.

Raises TypeError if dimension does not match. Raises LookupError if no conversion has been defined. (see define_conversion_factor_to).

define_conversion_factor_to(other, factor)

Defines a conversion factor between two BaseUnits.

self * factor = other

Parameters:

• self: (BaseUnit) ‘From’ unit in conversion.

• other: (BaseUnit) ‘To’ unit in conversion.

• factor: (float) Conversion factor.

After calling this method, both self and other will have stored conversion factors for one another, plus all other BaseUnits which self and other have previously defined.

Both self and other must have the same dimension, otherwise a TypeError will be raised.

Returns None.

get_dimension_tuple()

Returns a sorted tuple of (BaseDimension, exponent) pairs, that can be used as a dictionary key.

iter_base_dimensions()

Returns a dictionary of BaseDimension:exponent pairs, describing the dimension of this unit.

iter_base_units()