Coverage for /usr/lib/python3/dist-packages/sympy/physics/units/systems/natural.py: 100%

1""" 

2Naturalunit system. 

3 

4The natural system comes from "setting c = 1, hbar = 1". From the computer 

5point of view it means that we use velocity and action instead of length and 

6time. Moreover instead of mass we use energy. 

7""" 

8 

9from sympy.physics.units import DimensionSystem 

10from sympy.physics.units.definitions import c, eV, hbar 

11from sympy.physics.units.definitions.dimension_definitions import ( 

12 action, energy, force, frequency, length, mass, momentum, 

13 power, time, velocity) 

14from sympy.physics.units.prefixes import PREFIXES, prefix_unit 

15from sympy.physics.units.unitsystem import UnitSystem 

16 

17 

18# dimension system 

19_natural_dim = DimensionSystem( 

20 base_dims=(action, energy, velocity), 

21 derived_dims=(length, mass, time, momentum, force, power, frequency) 

22) 

23 

24units = prefix_unit(eV, PREFIXES) 

25 

26# unit system 

27natural = UnitSystem(base_units=(hbar, eV, c), units=units, name="Natural system")