87 lines
3.2 KiB
Python
87 lines
3.2 KiB
Python
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from sympy.physics.units import DimensionSystem, joule, second, ampere
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from sympy.core.numbers import Rational
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from sympy.core.singleton import S
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from sympy.physics.units.definitions import c, kg, m, s
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from sympy.physics.units.definitions.dimension_definitions import length, time
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from sympy.physics.units.quantities import Quantity
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from sympy.physics.units.unitsystem import UnitSystem
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from sympy.physics.units.util import convert_to
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def test_definition():
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# want to test if the system can have several units of the same dimension
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dm = Quantity("dm")
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base = (m, s)
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# base_dim = (m.dimension, s.dimension)
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ms = UnitSystem(base, (c, dm), "MS", "MS system")
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ms.set_quantity_dimension(dm, length)
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ms.set_quantity_scale_factor(dm, Rational(1, 10))
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assert set(ms._base_units) == set(base)
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assert set(ms._units) == {m, s, c, dm}
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# assert ms._units == DimensionSystem._sort_dims(base + (velocity,))
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assert ms.name == "MS"
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assert ms.descr == "MS system"
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def test_str_repr():
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assert str(UnitSystem((m, s), name="MS")) == "MS"
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assert str(UnitSystem((m, s))) == "UnitSystem((meter, second))"
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assert repr(UnitSystem((m, s))) == "<UnitSystem: (%s, %s)>" % (m, s)
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def test_convert_to():
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A = Quantity("A")
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A.set_global_relative_scale_factor(S.One, ampere)
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Js = Quantity("Js")
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Js.set_global_relative_scale_factor(S.One, joule*second)
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mksa = UnitSystem((m, kg, s, A), (Js,))
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assert convert_to(Js, mksa._base_units) == m**2*kg*s**-1/1000
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def test_extend():
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ms = UnitSystem((m, s), (c,))
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Js = Quantity("Js")
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Js.set_global_relative_scale_factor(1, joule*second)
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mks = ms.extend((kg,), (Js,))
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res = UnitSystem((m, s, kg), (c, Js))
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assert set(mks._base_units) == set(res._base_units)
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assert set(mks._units) == set(res._units)
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def test_dim():
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dimsys = UnitSystem((m, kg, s), (c,))
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assert dimsys.dim == 3
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def test_is_consistent():
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dimension_system = DimensionSystem([length, time])
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us = UnitSystem([m, s], dimension_system=dimension_system)
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assert us.is_consistent == True
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def test_get_units_non_prefixed():
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from sympy.physics.units import volt, ohm
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unit_system = UnitSystem.get_unit_system("SI")
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units = unit_system.get_units_non_prefixed()
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for prefix in ["giga", "tera", "peta", "exa", "zetta", "yotta", "kilo", "hecto", "deca", "deci", "centi", "milli", "micro", "nano", "pico", "femto", "atto", "zepto", "yocto"]:
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for unit in units:
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assert isinstance(unit, Quantity), f"{unit} must be a Quantity, not {type(unit)}"
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assert not unit.is_prefixed, f"{unit} is marked as prefixed"
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assert not unit.is_physical_constant, f"{unit} is marked as physics constant"
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assert not unit.name.name.startswith(prefix), f"Unit {unit.name} has prefix {prefix}"
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assert volt in units
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assert ohm in units
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def test_derived_units_must_exist_in_unit_system():
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for unit_system in UnitSystem._unit_systems.values():
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for preferred_unit in unit_system.derived_units.values():
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units = preferred_unit.atoms(Quantity)
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for unit in units:
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assert unit in unit_system._units, f"Unit {unit} is not in unit system {unit_system}"
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