83 lines
3.6 KiB
Python
83 lines
3.6 KiB
Python
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from sympy.core.singleton import S
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from sympy.functions.elementary.miscellaneous import sqrt
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from sympy.physics.units import UnitSystem, centimeter, gram, second, coulomb, charge, speed_of_light, current, mass, \
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length, voltage, magnetic_density, magnetic_flux
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from sympy.physics.units.definitions import coulombs_constant
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from sympy.physics.units.definitions.unit_definitions import statcoulomb, statampere, statvolt, volt, tesla, gauss, \
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weber, maxwell, debye, oersted, ohm, farad, henry, erg, ampere, coulomb_constant
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from sympy.physics.units.systems.mks import dimsys_length_weight_time
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One = S.One
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dimsys_cgs = dimsys_length_weight_time.extend(
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[],
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new_dim_deps={
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# Dimensional dependencies for derived dimensions
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"impedance": {"time": 1, "length": -1},
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"conductance": {"time": -1, "length": 1},
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"capacitance": {"length": 1},
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"inductance": {"time": 2, "length": -1},
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"charge": {"mass": S.Half, "length": S(3)/2, "time": -1},
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"current": {"mass": One/2, "length": 3*One/2, "time": -2},
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"voltage": {"length": -One/2, "mass": One/2, "time": -1},
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"magnetic_density": {"length": -One/2, "mass": One/2, "time": -1},
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"magnetic_flux": {"length": 3*One/2, "mass": One/2, "time": -1},
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}
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)
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cgs_gauss = UnitSystem(
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base_units=[centimeter, gram, second],
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units=[],
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name="cgs_gauss",
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dimension_system=dimsys_cgs)
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cgs_gauss.set_quantity_scale_factor(coulombs_constant, 1)
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cgs_gauss.set_quantity_dimension(statcoulomb, charge)
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cgs_gauss.set_quantity_scale_factor(statcoulomb, centimeter**(S(3)/2)*gram**(S.Half)/second)
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cgs_gauss.set_quantity_dimension(coulomb, charge)
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cgs_gauss.set_quantity_dimension(statampere, current)
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cgs_gauss.set_quantity_scale_factor(statampere, statcoulomb/second)
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cgs_gauss.set_quantity_dimension(statvolt, voltage)
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cgs_gauss.set_quantity_scale_factor(statvolt, erg/statcoulomb)
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cgs_gauss.set_quantity_dimension(volt, voltage)
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cgs_gauss.set_quantity_dimension(gauss, magnetic_density)
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cgs_gauss.set_quantity_scale_factor(gauss, sqrt(gram/centimeter)/second)
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cgs_gauss.set_quantity_dimension(tesla, magnetic_density)
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cgs_gauss.set_quantity_dimension(maxwell, magnetic_flux)
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cgs_gauss.set_quantity_scale_factor(maxwell, sqrt(centimeter**3*gram)/second)
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# SI units expressed in CGS-gaussian units:
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cgs_gauss.set_quantity_scale_factor(coulomb, 10*speed_of_light*statcoulomb)
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cgs_gauss.set_quantity_scale_factor(ampere, 10*speed_of_light*statcoulomb/second)
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cgs_gauss.set_quantity_scale_factor(volt, 10**6/speed_of_light*statvolt)
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cgs_gauss.set_quantity_scale_factor(weber, 10**8*maxwell)
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cgs_gauss.set_quantity_scale_factor(tesla, 10**4*gauss)
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cgs_gauss.set_quantity_scale_factor(debye, One/10**18*statcoulomb*centimeter)
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cgs_gauss.set_quantity_scale_factor(oersted, sqrt(gram/centimeter)/second)
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cgs_gauss.set_quantity_scale_factor(ohm, 10**5/speed_of_light**2*second/centimeter)
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cgs_gauss.set_quantity_scale_factor(farad, One/10**5*speed_of_light**2*centimeter)
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cgs_gauss.set_quantity_scale_factor(henry, 10**5/speed_of_light**2/centimeter*second**2)
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# Coulomb's constant:
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cgs_gauss.set_quantity_dimension(coulomb_constant, 1)
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cgs_gauss.set_quantity_scale_factor(coulomb_constant, 1)
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__all__ = [
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'ohm', 'tesla', 'maxwell', 'speed_of_light', 'volt', 'second', 'voltage',
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'debye', 'dimsys_length_weight_time', 'centimeter', 'coulomb_constant',
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'farad', 'sqrt', 'UnitSystem', 'current', 'charge', 'weber', 'gram',
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'statcoulomb', 'gauss', 'S', 'statvolt', 'oersted', 'statampere',
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'dimsys_cgs', 'coulomb', 'magnetic_density', 'magnetic_flux', 'One',
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'length', 'erg', 'mass', 'coulombs_constant', 'henry', 'ampere',
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'cgs_gauss',
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]
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