def _unfold(self, op: Operator, n: int) -> Optional[Operator]:
""" Unroll all possible operators from the grammar `g` starting from non-terminal `op` after `n` derivations.
Parameters
----------
op : Operator
starting rule (e.g., `g.start`)
n : int
number of derivations
Returns
-------
Optional[Operator]
"""
if isinstance(op, BasePipeline):
steps = op.steps()
new_steps = [self._unfold(sop, n) for sop in op.steps()]
step_map = {steps[i]: new_steps[i] for i in range(len(steps))}
new_edges = [(step_map[s], step_map[d]) for s, d in op.edges()]
if not None in new_steps:
return get_pipeline_of_applicable_type(new_steps, new_edges,
True)
return None
if isinstance(op, OperatorChoice):
steps = [
s for s in (self._unfold(sop, n) for sop in op.steps()) if s
]
return make_choice(*steps) if steps else None
if isinstance(op, NonTerminal):
return self._unfold(self._variables[op.name()], n -
1) if n > 0 else None
if isinstance(op, IndividualOp):
return op
assert False, f"Unknown operator {op}"
def _sample(self, op: Operator, n: int) -> Optional[Operator]:
"""
Sample the grammar `g` starting from `g.start`, that is, choose one element at random for each possible choices.
Parameters
----------
op : Operator
starting rule (e.g., `g.start`)
n : int
number of derivations
Returns
-------
Optional[Operator]
"""
if isinstance(op, BasePipeline):
steps = op.steps()
new_steps = [self._sample(sop, n) for sop in op.steps()]
step_map = {steps[i]: new_steps[i] for i in range(len(steps))}
new_edges = [(step_map[s], step_map[d]) for s, d in op.edges()]
if not None in new_steps:
return get_pipeline_of_applicable_type(new_steps, new_edges,
True)
return None
if isinstance(op, OperatorChoice):
return self._sample(random.choice(op.steps()), n)
if isinstance(op, NonTerminal):
return self._sample(getattr(self, op.name()), n -
1) if n > 0 else None
if isinstance(op, IndividualOp):
return op
assert False, f"Unknown operator {op}"
def set_operator_params(op: Ops.Operator,
**impl_params) -> Ops.TrainableOperator:
"""May return a new operator, in which case the old one should be overwritten
"""
if isinstance(op, Ops.PlannedIndividualOp):
main_params, partitioned_sub_params = partition_sklearn_params(
impl_params)
hyper = op._hyperparams
if hyper is None:
hyper = {}
# we set the sub params first
for sub_key, sub_params in partitioned_sub_params.items():
set_structured_params(sub_key, sub_params, hyper)
# we have now updated any nested operators
# (if this is a higher order operator)
# and can work on the main operator
all_params = {**main_params, **hyper}
return op.set_params(**all_params)
elif isinstance(op, Ops.BasePipeline):
steps = op.steps()
main_params, partitioned_sub_params = partition_sklearn_params(
impl_params)
assert not main_params, f"Unexpected non-nested arguments {main_params}"
found_names: Dict[str, int] = {}
step_map: Dict[Ops.Operator, Ops.TrainableOperator] = {}
for s in steps:
name = s.name()
name_index = 0
params: Dict[str, Any] = {}
if name in found_names:
name_index = found_names[name] + 1
found_names[name] = name_index
uname = make_indexed_name(name, name_index)
if uname in partitioned_sub_params:
params = partitioned_sub_params[uname]
else:
found_names[name] = 0
uname = make_degen_indexed_name(name, 0)
if uname in partitioned_sub_params:
params = partitioned_sub_params[uname]
assert name not in partitioned_sub_params
elif name in partitioned_sub_params:
params = partitioned_sub_params[name]
new_s = set_operator_params(s, **params)
if s != new_s:
step_map[s] = new_s
# make sure that no parameters were passed in for operations
# that are not actually part of this pipeline
for k in partitioned_sub_params.keys():
n, i = get_name_and_index(k)
assert n in found_names and i <= found_names[n]
if step_map:
op._subst_steps(step_map)
if not isinstance(op, Ops.TrainablePipeline):
# As a result of choices made, we may now be a TrainableIndividualOp
ret = Ops.make_pipeline_graph(op.steps(),
op.edges(),
ordered=True)
if not isinstance(ret, Ops.TrainableOperator):
assert False
return ret
else:
return op
else:
assert isinstance(op, Ops.TrainableOperator)
return op
elif isinstance(op, Ops.OperatorChoice):
choices = op.steps()
choice_index: int
choice_params: Dict[str, Any]
if len(choices) == 1:
choice_index = 0
chosen_params = impl_params
else:
(choice_index,
chosen_params) = partition_sklearn_choice_params(impl_params)
assert 0 <= choice_index and choice_index < len(choices)
choice: Ops.Operator = choices[choice_index]
new_step = set_operator_params(choice, **chosen_params)
# we remove the OperatorChoice, replacing it with the branch that was taken
return new_step
else:
assert False, f"Not yet supported operation of type: {op.__class__.__name__}"