def adjoint(self, red_op, bin_op, root, targets):
bin_unit = to_funsor(ops.UNITS[bin_op])
adjoint_values = defaultdict(lambda: bin_unit)
reached_root = False
while self.tape:
output, fn, inputs = self.tape.pop()
if not reached_root:
if output is root:
reached_root = True
else:
continue
# reverse the effects of alpha-renaming
with interpretation(reflect):
other_subs = tuple((name, to_funsor(name.split("__BOUND")[0], domain))
for name, domain in output.inputs.items() if "__BOUND" in name)
inputs = _alpha_unmangle(substitute(fn(*inputs), other_subs))
output = type(output)(*_alpha_unmangle(substitute(output, other_subs)))
in_adjs = adjoint_ops(fn, red_op, bin_op, adjoint_values[output], *inputs)
for v, adjv in in_adjs.items():
adjoint_values[v] = bin_op(adjoint_values[v], adjv)
target_adjs = {}
for v in targets:
target_adjs[v] = adjoint_values[v]
if not isinstance(v, Variable):
target_adjs[v] = bin_op(target_adjs[v], v)
return target_adjs
def _alpha_convert(self, alpha_subs):
assert self.bound.issuperset(alpha_subs)
reduced_vars = frozenset(alpha_subs.get(k, k) for k in self.reduced_vars)
alpha_subs = {k: to_funsor(v, self.integrand.inputs.get(k, self.log_measure.inputs.get(k)))
for k, v in alpha_subs.items()}
log_measure = substitute(self.log_measure, alpha_subs)
integrand = substitute(self.integrand, alpha_subs)
return log_measure, integrand, reduced_vars
def _alpha_convert(self, alpha_subs):
assert self.bound.issuperset(alpha_subs)
time = Variable(alpha_subs.get(self.time.name, self.time.name),
self.time.output)
step = frozenset((alpha_subs.get(k, k), alpha_subs.get(v, v))
for k, v in self.step.items())
step_names = frozenset((alpha_subs.get(k, k), v)
for k, v in self.step_names.items())
alpha_subs = {k: to_funsor(v, self.trans.inputs[k])
for k, v in alpha_subs.items()
if k in self.trans.inputs}
trans = substitute(self.trans, alpha_subs)
return self.sum_op, self.prod_op, trans, time, step, step_names
def materialize(x):
"""
Attempt to convert a Funsor to a :class:`~funsor.terms.Number` or
:class:`Tensor` by substituting :func:`arange` s into its free variables.
"""
assert isinstance(x, Funsor)
if isinstance(x, (Number, Tensor)):
return x
subs = []
for name, domain in x.inputs.items():
if isinstance(domain.dtype, integer_types):
subs.append((name, arange(name, domain.dtype)))
subs = tuple(subs)
return substitute(x, subs)
def materialize(x):
"""
Attempt to convert a Funsor to a :class:`~funsor.terms.Number` or
:class:`numpy.ndarray` by substituting :func:`arange` s into its free variables.
"""
assert isinstance(x, Funsor)
if isinstance(x, (Number, Array)):
return x
subs = []
for name, domain in x.inputs.items():
if not isinstance(domain.dtype, integer_types):
raise ValueError(
'materialize() requires integer free variables but found '
'"{}" of domain {}'.format(name, domain))
assert not domain.shape
subs.append((name, arange(name, domain.dtype)))
subs = tuple(subs)
return substitute(x, subs)
