47 lines
1.5 KiB
Python
47 lines
1.5 KiB
Python
"""
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MKS unit system.
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MKS stands for "meter, kilogram, second".
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"""
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from sympy.physics.units import UnitSystem
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from sympy.physics.units.definitions import gravitational_constant, hertz, joule, newton, pascal, watt, speed_of_light, gram, kilogram, meter, second
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from sympy.physics.units.definitions.dimension_definitions import (
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acceleration, action, energy, force, frequency, momentum,
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power, pressure, velocity, length, mass, time)
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from sympy.physics.units.prefixes import PREFIXES, prefix_unit
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from sympy.physics.units.systems.length_weight_time import dimsys_length_weight_time
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dims = (velocity, acceleration, momentum, force, energy, power, pressure,
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frequency, action)
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units = [meter, gram, second, joule, newton, watt, pascal, hertz]
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all_units = []
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# Prefixes of units like gram, joule, newton etc get added using `prefix_unit`
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# in the for loop, but the actual units have to be added manually.
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all_units.extend([gram, joule, newton, watt, pascal, hertz])
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for u in units:
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all_units.extend(prefix_unit(u, PREFIXES))
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all_units.extend([gravitational_constant, speed_of_light])
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# unit system
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MKS = UnitSystem(base_units=(meter, kilogram, second), units=all_units, name="MKS", dimension_system=dimsys_length_weight_time, derived_units={
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power: watt,
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time: second,
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pressure: pascal,
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length: meter,
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frequency: hertz,
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mass: kilogram,
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force: newton,
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energy: joule,
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velocity: meter/second,
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acceleration: meter/(second**2),
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})
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__all__ = [
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'MKS', 'units', 'all_units', 'dims',
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]
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