Initialisation du repository de Beta

venv/lib/python3.12/site-packages/sympy/physics/units/systems/natural.py

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+"""
+Naturalunit system.
+
+The natural system comes from "setting c = 1, hbar = 1". From the computer
+point of view it means that we use velocity and action instead of length and
+time. Moreover instead of mass we use energy.
+"""
+
+from sympy.physics.units import DimensionSystem
+from sympy.physics.units.definitions import c, eV, hbar
+from sympy.physics.units.definitions.dimension_definitions import (
+    action, energy, force, frequency, length, mass, momentum,
+    power, time, velocity)
+from sympy.physics.units.prefixes import PREFIXES, prefix_unit
+from sympy.physics.units.unitsystem import UnitSystem
+
+
+# dimension system
+_natural_dim = DimensionSystem(
+    base_dims=(action, energy, velocity),
+    derived_dims=(length, mass, time, momentum, force, power, frequency)
+)
+
+units = prefix_unit(eV, PREFIXES)
+
+# unit system
+natural = UnitSystem(base_units=(hbar, eV, c), units=units, name="Natural system")