def __init__(self, mapping={}):
"""Create a rational-valued function"""
if isinstance(mapping, Mapping):
self._mapping = {arg: _make_rational(value)
for arg, value in mapping.iteritems()}
else:
raise TypeError("specify a mapping")
def __add__(self, other):
"""Also allow addition of gambles and scalars"""
if isinstance(other, Gamble):
return Vector.__add__(self, other)
else:
other = _make_rational(other)
return type(self)({arg: value + other
for arg, value in self.iteritems()})
def set_upper_pr(self, data, val):
"""Set the upper probability/prevision (expectation) of an event/gamble
:arg `data`: the gamble for which a probability/prevision value is given
:type `data`: arguments accepted by the :class:`~murasyp.gambles.Gamble`
constructor
:arg `val`: the probability/prevision value
:type `val`: a representation of :class:`~numbers.Real`
The nontrivial cone corresponing to the prevision specification is
calculated and added to the set of desirable gambles.
>>> D = DesirSet()
>>> D.set_upper_pr(Gamble({'a', 'b'}) | {'a', 'b', 'c'}, .4)
>>> D
DesirSet([Cone([Ray({'a': 1, 'c': 1, 'b': 1}), Ray({'a': -1, 'c': '2/3', 'b': -1})])])
.. note::
The domain of the input gamble determines the conditioning event.
"""
self.set_lower_pr(-Gamble(data), -_make_rational(val))
def __div__(self, other):
"""Scalar division of rational-valued functions"""
other = _make_rational(other)
return type(self)({arg: value / other
for arg, value in self.iteritems()})
def __mul__(self, other):
"""Scalar multiplication of rational-valued functions"""
other = _make_rational(other)
return type(self)({arg: value * other
for arg, value in self.iteritems()})
def __div__(self, other):
"""Scalar division of rays"""
other = _make_rational(other)
return Gamble(self) / other
def __div__(self, other):
"""Scalar division of mass assignments"""
other = _make_rational(other)
return Vector(self) / other
