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