NatPy 0.0.3

Convert the units of particle physics quantities.

NatPy

Convert the units of particle physics quantities

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Packages needed:

• astropy
• numpy

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Basic Usage

Code levarages astropy.units.core.Unit and astropy.units.quantity.Quantity objects.

1. Run import natpy.
2. Access physical constants with symbol:

>>> natpy.const.c
<class 'astropy.constants.codata2018.CODATA2018'> name='Speed of light in vacuum' value=299792458.0 uncertainty=0.0 unit='m / s' reference='CODATA 2018'>


>>> natpy.const.hbar
<class 'astropy.constants.codata2018.CODATA2018'> name='Reduced Planck constant' value=1.0545718176461565e-34 uncertainty=0.0 unit='J s' reference='CODATA 2018'>

3. Specify base of natural units with natpy.set_active_units(). Pass a string corresponding to a list of default natural units, or a list of physical constants to set your own. List of default bases found in natpy/default_values.py.

4. Run natpy.convert() to convert between units, including necessary factors of natural units. Pass just unit objects to obtain conversion factors. Pass quantity objects to perform conversions. E.g.

# kg to keV
>>> natpy.convert(u.kg, u.keV)
5.6173581670146864e+32

# Electron mass
>>> me = natpy.convert(9.11e-31 * u.kg, u.keV)
>>> me
<Quantity 511.74132902 keV>

# Energy of electron with momentum of 1 MeV 
>>> p = 1 * u.MeV
>>> E = np.sqrt(p**2 + me**2)

# Convert to SI units
>>> natpy.convert(E,u.J)
<Quantity 1.79926309e-13 J>

Note: Summing quanties requires conventionally equivalent units.

6. See tests/convert_test.py for more examples.