autogen/flaml/searcher/variant_generator.py
Chi Wang b3bb00966d
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2021-07-20 17:00:44 -07:00

317 lines
11 KiB
Python

'''
Copyright 2020 The Ray Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
This source file is adapted here because ray does not fully support Windows.
Copyright (c) Microsoft Corporation.
'''
import copy
import logging
from collections.abc import Mapping
from typing import Any, Dict, Generator, List, Optional, Tuple
import numpy
import random
from ..tune.sample import Categorical, Domain, Function
logger = logging.getLogger(__name__)
def flatten_dict(dt, delimiter="/", prevent_delimiter=False):
dt = copy.deepcopy(dt)
if prevent_delimiter and any(delimiter in key for key in dt):
# Raise if delimiter is any of the keys
raise ValueError(
"Found delimiter `{}` in key when trying to flatten array."
"Please avoid using the delimiter in your specification.")
while any(isinstance(v, dict) for v in dt.values()):
remove = []
add = {}
for key, value in dt.items():
if isinstance(value, dict):
for subkey, v in value.items():
if prevent_delimiter and delimiter in subkey:
# Raise if delimiter is in any of the subkeys
raise ValueError(
"Found delimiter `{}` in key when trying to "
"flatten array. Please avoid using the delimiter "
"in your specification.")
add[delimiter.join([key, str(subkey)])] = v
remove.append(key)
dt.update(add)
for k in remove:
del dt[k]
return dt
def unflatten_dict(dt, delimiter="/"):
"""Unflatten dict. Does not support unflattening lists."""
dict_type = type(dt)
out = dict_type()
for key, val in dt.items():
path = key.split(delimiter)
item = out
for k in path[:-1]:
item = item.setdefault(k, dict_type())
item[path[-1]] = val
return out
class TuneError(Exception):
"""General error class raised by ray.tune."""
pass
def generate_variants(
unresolved_spec: Dict) -> Generator[Tuple[Dict, Dict], None, None]:
"""Generates variants from a spec (dict) with unresolved values.
There are two types of unresolved values:
Grid search: These define a grid search over values. For example, the
following grid search values in a spec will produce six distinct
variants in combination:
"activation": grid_search(["relu", "tanh"])
"learning_rate": grid_search([1e-3, 1e-4, 1e-5])
Lambda functions: These are evaluated to produce a concrete value, and
can express dependencies or conditional distributions between values.
They can also be used to express random search (e.g., by calling
into the `random` or `np` module).
"cpu": lambda spec: spec.config.num_workers
"batch_size": lambda spec: random.uniform(1, 1000)
Finally, to support defining specs in plain JSON / YAML, grid search
and lambda functions can also be defined alternatively as follows:
"activation": {"grid_search": ["relu", "tanh"]}
"cpu": {"eval": "spec.config.num_workers"}
Use `format_vars` to format the returned dict of hyperparameters.
Yields:
(Dict of resolved variables, Spec object)
"""
for resolved_vars, spec in _generate_variants(unresolved_spec):
assert not _unresolved_values(spec)
yield resolved_vars, spec
def grid_search(values: List) -> Dict[str, List]:
"""Convenience method for specifying grid search over a value.
Arguments:
values: An iterable whose parameters will be gridded.
"""
return {"grid_search": values}
_STANDARD_IMPORTS = {
"random": random,
"np": numpy,
}
_MAX_RESOLUTION_PASSES = 20
def parse_spec_vars(spec: Dict) -> Tuple[List[Tuple[Tuple, Any]], List[Tuple[
Tuple, Any]], List[Tuple[Tuple, Any]]]:
resolved, unresolved = _split_resolved_unresolved_values(spec)
resolved_vars = list(resolved.items())
if not unresolved:
return resolved_vars, [], []
grid_vars = []
domain_vars = []
for path, value in unresolved.items():
if value.is_grid():
grid_vars.append((path, value))
else:
domain_vars.append((path, value))
grid_vars.sort()
return resolved_vars, domain_vars, grid_vars
def _generate_variants(spec: Dict) -> Tuple[Dict, Dict]:
spec = copy.deepcopy(spec)
_, domain_vars, grid_vars = parse_spec_vars(spec)
if not domain_vars and not grid_vars:
yield {}, spec
return
grid_search = _grid_search_generator(spec, grid_vars)
for resolved_spec in grid_search:
resolved_vars = _resolve_domain_vars(resolved_spec, domain_vars)
for resolved, spec in _generate_variants(resolved_spec):
for path, value in grid_vars:
resolved_vars[path] = _get_value(spec, path)
for k, v in resolved.items():
if (k in resolved_vars and v != resolved_vars[k]
and _is_resolved(resolved_vars[k])):
raise ValueError(
"The variable `{}` could not be unambiguously "
"resolved to a single value. Consider simplifying "
"your configuration.".format(k))
resolved_vars[k] = v
yield resolved_vars, spec
def assign_value(spec: Dict, path: Tuple, value: Any):
for k in path[:-1]:
spec = spec[k]
spec[path[-1]] = value
def _get_value(spec: Dict, path: Tuple) -> Any:
for k in path:
spec = spec[k]
return spec
def _resolve_domain_vars(spec: Dict,
domain_vars: List[Tuple[Tuple, Domain]]) -> Dict:
resolved = {}
error = True
num_passes = 0
while error and num_passes < _MAX_RESOLUTION_PASSES:
num_passes += 1
error = False
for path, domain in domain_vars:
if path in resolved:
continue
try:
value = domain.sample(_UnresolvedAccessGuard(spec))
except RecursiveDependencyError as e:
error = e
except Exception:
raise ValueError(
"Failed to evaluate expression: {}: {}".format(
path, domain))
else:
assign_value(spec, path, value)
resolved[path] = value
if error:
raise error
return resolved
def _grid_search_generator(unresolved_spec: Dict,
grid_vars: List) -> Generator[Dict, None, None]:
value_indices = [0] * len(grid_vars)
def increment(i):
value_indices[i] += 1
if value_indices[i] >= len(grid_vars[i][1]):
value_indices[i] = 0
if i + 1 < len(value_indices):
return increment(i + 1)
else:
return True
return False
if not grid_vars:
yield unresolved_spec
return
while value_indices[-1] < len(grid_vars[-1][1]):
spec = copy.deepcopy(unresolved_spec)
for i, (path, values) in enumerate(grid_vars):
assign_value(spec, path, values[value_indices[i]])
yield spec
if grid_vars:
done = increment(0)
if done:
break
def _is_resolved(v) -> bool:
resolved, _ = _try_resolve(v)
return resolved
def _try_resolve(v) -> Tuple[bool, Any]:
if isinstance(v, Domain):
# Domain to sample from
return False, v
elif isinstance(v, dict) and len(v) == 1 and "eval" in v:
# Lambda function in eval syntax
return False, Function(
lambda spec: eval(v["eval"], _STANDARD_IMPORTS, {"spec": spec}))
elif isinstance(v, dict) and len(v) == 1 and "grid_search" in v:
# Grid search values
grid_values = v["grid_search"]
if not isinstance(grid_values, list):
raise TuneError(
"Grid search expected list of values, got: {}".format(
grid_values))
return False, Categorical(grid_values).grid()
return True, v
def _split_resolved_unresolved_values(
spec: Dict) -> Tuple[Dict[Tuple, Any], Dict[Tuple, Any]]:
resolved_vars = {}
unresolved_vars = {}
for k, v in spec.items():
resolved, v = _try_resolve(v)
if not resolved:
unresolved_vars[(k, )] = v
elif isinstance(v, dict):
# Recurse into a dict
_resolved_children, _unresolved_children = \
_split_resolved_unresolved_values(v)
for (path, value) in _resolved_children.items():
resolved_vars[(k, ) + path] = value
for (path, value) in _unresolved_children.items():
unresolved_vars[(k, ) + path] = value
elif isinstance(v, list):
# Recurse into a list
for i, elem in enumerate(v):
_resolved_children, _unresolved_children = \
_split_resolved_unresolved_values({i: elem})
for (path, value) in _resolved_children.items():
resolved_vars[(k, ) + path] = value
for (path, value) in _unresolved_children.items():
unresolved_vars[(k, ) + path] = value
else:
resolved_vars[(k, )] = v
return resolved_vars, unresolved_vars
def _unresolved_values(spec: Dict) -> Dict[Tuple, Any]:
return _split_resolved_unresolved_values(spec)[1]
def has_unresolved_values(spec: Dict) -> bool:
return True if _unresolved_values(spec) else False
class _UnresolvedAccessGuard(dict):
def __init__(self, *args, **kwds):
super(_UnresolvedAccessGuard, self).__init__(*args, **kwds)
self.__dict__ = self
def __getattribute__(self, item):
value = dict.__getattribute__(self, item)
if not _is_resolved(value):
raise RecursiveDependencyError(
"`{}` recursively depends on {}".format(item, value))
elif isinstance(value, dict):
return _UnresolvedAccessGuard(value)
else:
return value
class RecursiveDependencyError(Exception):
def __init__(self, msg: str):
Exception.__init__(self, msg)