def __mul__(self, unit):
"""
SiPrefix * BaseUnit yields new BaseUnit
SiPrefix * ScaledUnit yields new ScaledUnit
SiPrefix * Unit with exactly one BaseUnit or ScaledUnit yields new Unit
"""
if isinstance(unit, BaseUnit):
# BaseUnit version
symbol = self.symbol + unit.symbol
name = self.prefix + unit.name
factor = self.factor
# TODO - check for existing BaseUnit with same name, symbol, and factor
new_base_unit = BaseUnit(unit.dimension, name, symbol)
new_base_unit.define_conversion_factor_to(unit, factor)
return new_base_unit
elif isinstance(unit, ScaledUnit):
# ScaledUnit version
symbol = self.symbol + unit.symbol
name = self.prefix + unit.name
factor = self.factor * unit.factor
# TODO - check for existing BaseUnit with same name, symbol, and factor
return ScaledUnit(factor, unit.master, name, symbol)
elif isinstance(unit, Unit):
base_units = list(unit.iter_base_or_scaled_units())
if 1 != len(base_units):
raise TypeError('Unit prefix "%s" can only be with simple Units containing one component.' % self.prefix)
if 1 != base_units[0][1]:
raise TypeError('Unit prefix "%s" can only be with simple Units with an exponent of 1.' % self.prefix)
base_unit = base_units[0][0]
# Delegate to Base or Scaled Unit multiply
new_base_unit = self * base_unit
new_unit = Unit({new_base_unit: 1.0})
return new_unit
else:
raise TypeError('Unit prefix "%s" can only be applied to a Unit, BaseUnit, or ScaledUnit.' % self.prefix)
def __mul__(self, unit):
"""
SiPrefix * BaseUnit yields new BaseUnit
SiPrefix * ScaledUnit yields new ScaledUnit
SiPrefix * Unit with exactly one BaseUnit or ScaledUnit yields new Unit
"""
if isinstance(unit, BaseUnit):
# BaseUnit version
symbol = self.symbol + unit.symbol
name = self.prefix + unit.name
factor = self.factor
# TODO - check for existing BaseUnit with same name, symbol, and factor
new_base_unit = BaseUnit(unit.dimension, name, symbol)
new_base_unit.define_conversion_factor_to(unit, factor)
return new_base_unit
elif isinstance(unit, ScaledUnit):
# ScaledUnit version
symbol = self.symbol + unit.symbol
name = self.prefix + unit.name
factor = self.factor * unit.factor
# TODO - check for existing BaseUnit with same name, symbol, and factor
return ScaledUnit(factor, unit.master, name, symbol)
elif isinstance(unit, Unit):
base_units = list(unit.iter_base_or_scaled_units())
if 1 != len(base_units):
raise TypeError('Unit prefix "%s" can only be with simple Units containing one component.' % self.prefix)
if 1 != base_units[0][1]:
raise TypeError('Unit prefix "%s" can only be with simple Units with an exponent of 1.' % self.prefix)
base_unit = base_units[0][0]
# Delegate to Base or Scaled Unit multiply
new_base_unit = self * base_unit
new_unit = Unit({new_base_unit: 1.0})
return new_unit
else:
raise TypeError('Unit prefix "%s" can only be applied to a Unit, BaseUnit, or ScaledUnit.' % self.prefix)
def create_unit(self, scale, name, symbol):
"""
Convenience method for creating a new simple unit from another simple unit.
Both units must consist of a single BaseUnit.
"""
# TODO - also handle non-simple units, i.e. units with multiple BaseUnits/ScaledUnits
assert len(self._top_base_units) == 1
assert len(self._scaled_units) == 0
dimension = self._top_base_units.iterkeys().next()
base_unit_dict = self._top_base_units[dimension]
assert len(base_unit_dict) == 1
parent_base_unit = base_unit_dict.iterkeys().next()
parent_exponent = base_unit_dict[parent_base_unit]
new_base_unit = BaseUnit(parent_base_unit.dimension, name, symbol)
# BaseUnit scale might be different depending on exponent
true_scale = scale
if parent_exponent != 1.0:
true_scale = math.pow(scale, 1.0/parent_exponent)
new_base_unit.define_conversion_factor_to(parent_base_unit, true_scale)
new_unit = Unit({new_base_unit: 1.0})
return new_unit
#####################
### DIMENSIONLESS ###
#####################
# dimensionless = Unit({}); # defined in unit.py
##############
### LENGTH ###
##############
meter_base_unit = BaseUnit(length_dimension, "meter", "m")
meters = meter = Unit({meter_base_unit: 1.0})
define_prefixed_units(meter_base_unit, module=sys.modules[__name__])
angstrom_base_unit = BaseUnit(length_dimension, "angstrom", "A")
angstrom_base_unit.define_conversion_factor_to(meter_base_unit, 1e-10)
angstroms = angstrom = Unit({angstrom_base_unit: 1.0})
planck_length_base_unit = BaseUnit(length_dimension, "Planck length", "l_P")
planck_length_base_unit.define_conversion_factor_to(meter_base_unit,
1.61625281e-35)
inch_base_unit = BaseUnit(length_dimension, "inch", "in")
inch_base_unit.define_conversion_factor_to(centimeter_base_unit, 2.5400)
inch = inches = Unit({inch_base_unit: 1.0})
foot_base_unit = BaseUnit(length_dimension, "foot", "ft")
foot_base_unit.define_conversion_factor_to(inch_base_unit, 12.0)
foot = feet = Unit({foot_base_unit: 1.0})
yard_base_unit = BaseUnit(length_dimension, "yard", "yd")
#####################
### DIMENSIONLESS ###
#####################
# dimensionless = Unit({}); # defined in unit.py
##############
### LENGTH ###
##############
meter_base_unit = BaseUnit(length_dimension, "meter", "m")
meters = meter = Unit({meter_base_unit: 1.0})
define_prefixed_units(meter_base_unit, module = sys.modules[__name__])
angstrom_base_unit = BaseUnit(length_dimension, "angstrom", "A")
angstrom_base_unit.define_conversion_factor_to(meter_base_unit, 1e-10)
angstroms = angstrom = Unit({angstrom_base_unit: 1.0})
planck_length_base_unit = BaseUnit(length_dimension, "Planck length", "l_P")
planck_length_base_unit.define_conversion_factor_to(meter_base_unit, 1.61625281e-35)
inch_base_unit = BaseUnit(length_dimension, "inch", "in")
inch_base_unit.define_conversion_factor_to(centimeter_base_unit, 2.5400)
inch = inches = Unit({inch_base_unit: 1.0})
foot_base_unit = BaseUnit(length_dimension, "foot", "ft")
foot_base_unit.define_conversion_factor_to(inch_base_unit, 12.0)
foot = feet = Unit({foot_base_unit: 1.0})
yard_base_unit = BaseUnit(length_dimension, "yard", "yd")
yard_base_unit.define_conversion_factor_to(foot_base_unit, 3.0)
