560 lines
21 KiB
Python
560 lines
21 KiB
Python
import copy
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import logging
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from functools import partial
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from typing import Any, Dict, List, Optional
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import numpy as np
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# Use cloudpickle instead of pickle to make lambda funcs in HyperOpt pickleable
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from ray import cloudpickle
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from ray.tune.error import TuneError
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from ray.tune.result import DEFAULT_METRIC
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from ray.tune.search import (
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UNDEFINED_METRIC_MODE,
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UNDEFINED_SEARCH_SPACE,
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UNRESOLVED_SEARCH_SPACE,
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Searcher,
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)
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from ray.tune.search.sample import (
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Categorical,
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Domain,
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Float,
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Integer,
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LogUniform,
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Normal,
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Quantized,
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Uniform,
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)
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from ray.tune.search.variant_generator import assign_value, parse_spec_vars
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from ray.tune.utils import flatten_dict
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try:
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hyperopt_logger = logging.getLogger("hyperopt")
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hyperopt_logger.setLevel(logging.WARNING)
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import hyperopt as hpo
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from hyperopt.pyll import Apply
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except ImportError:
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hpo = None
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Apply = None
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logger = logging.getLogger(__name__)
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HYPEROPT_UNDEFINED_DETAILS = (
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" This issue can also come up with HyperOpt if your search space only "
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"contains constant variables, which is not supported by HyperOpt. In that case, "
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"don't pass any searcher or add sample variables to the search space."
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)
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class HyperOptSearch(Searcher):
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"""A wrapper around HyperOpt to provide trial suggestions.
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HyperOpt a Python library for serial and parallel optimization
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over awkward search spaces, which may include real-valued, discrete,
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and conditional dimensions. More info can be found at
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http://hyperopt.github.io/hyperopt.
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HyperOptSearch uses the Tree-structured Parzen Estimators algorithm,
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though it can be trivially extended to support any algorithm HyperOpt
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supports.
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To use this search algorithm, you will need to install HyperOpt:
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.. code-block:: bash
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pip install -U hyperopt
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Parameters:
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space: HyperOpt configuration. Parameters will be sampled
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from this configuration and will be used to override
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parameters generated in the variant generation process.
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metric: The training result objective value attribute. If None
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but a mode was passed, the anonymous metric `_metric` will be used
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per default.
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mode: One of {min, max}. Determines whether objective is
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minimizing or maximizing the metric attribute.
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points_to_evaluate: Initial parameter suggestions to be run
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first. This is for when you already have some good parameters
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you want to run first to help the algorithm make better suggestions
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for future parameters. Needs to be a list of dicts containing the
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configurations.
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n_initial_points: number of random evaluations of the
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objective function before starting to approximate it with
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tree parzen estimators. Defaults to 20.
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random_state_seed: seed for reproducible
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results. Defaults to None.
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gamma: parameter governing the tree parzen
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estimators suggestion algorithm. Defaults to 0.25.
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Tune automatically converts search spaces to HyperOpt's format:
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.. code-block:: python
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config = {
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'width': tune.uniform(0, 20),
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'height': tune.uniform(-100, 100),
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'activation': tune.choice(["relu", "tanh"])
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}
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current_best_params = [{
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'width': 10,
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'height': 0,
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'activation': "relu",
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}]
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hyperopt_search = HyperOptSearch(
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metric="mean_loss", mode="min",
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points_to_evaluate=current_best_params)
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tuner = tune.Tuner(
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trainable,
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tune_config=tune.TuneConfig(
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search_alg=hyperopt_search
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),
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param_space=config
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)
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tuner.fit()
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If you would like to pass the search space manually, the code would
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look like this:
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.. code-block:: python
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space = {
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'width': hp.uniform('width', 0, 20),
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'height': hp.uniform('height', -100, 100),
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'activation': hp.choice("activation", ["relu", "tanh"])
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}
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current_best_params = [{
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'width': 10,
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'height': 0,
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'activation': "relu",
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}]
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hyperopt_search = HyperOptSearch(
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space, metric="mean_loss", mode="min",
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points_to_evaluate=current_best_params)
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tuner = tune.Tuner(
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trainable,
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tune_config=tune.TuneConfig(
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search_alg=hyperopt_search
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),
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)
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tuner.fit()
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"""
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def __init__(
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self,
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space: Optional[Dict] = None,
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metric: Optional[str] = None,
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mode: Optional[str] = None,
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points_to_evaluate: Optional[List[Dict]] = None,
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n_initial_points: int = 20,
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random_state_seed: Optional[int] = None,
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gamma: float = 0.25,
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):
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assert (
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hpo is not None
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), "HyperOpt must be installed! Run `pip install hyperopt`."
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if mode:
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assert mode in ["min", "max"], "`mode` must be 'min' or 'max'."
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super(HyperOptSearch, self).__init__(
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metric=metric,
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mode=mode,
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)
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# hyperopt internally minimizes, so "max" => -1
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if mode == "max":
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self.metric_op = -1.0
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elif mode == "min":
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self.metric_op = 1.0
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if n_initial_points is None:
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self.algo = hpo.tpe.suggest
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else:
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self.algo = partial(hpo.tpe.suggest, n_startup_jobs=n_initial_points)
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if gamma is not None:
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self.algo = partial(self.algo, gamma=gamma)
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self._points_to_evaluate = copy.deepcopy(points_to_evaluate)
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self._live_trial_mapping = {}
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self.rstate = np.random.RandomState(random_state_seed)
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self.domain = None
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if isinstance(space, dict) and space:
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resolved_vars, domain_vars, grid_vars = parse_spec_vars(space)
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if domain_vars or grid_vars:
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logger.warning(
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UNRESOLVED_SEARCH_SPACE.format(par="space", cls=type(self))
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)
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space = self.convert_search_space(space)
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self._space = space
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self._setup_hyperopt()
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def _setup_hyperopt(self) -> None:
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from hyperopt.fmin import generate_trials_to_calculate
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if not self._space:
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raise RuntimeError(
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UNDEFINED_SEARCH_SPACE.format(
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cls=self.__class__.__name__, space="space"
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)
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+ HYPEROPT_UNDEFINED_DETAILS
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)
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if self._metric is None and self._mode:
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# If only a mode was passed, use anonymous metric
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self._metric = DEFAULT_METRIC
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if self._points_to_evaluate is None:
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self._hpopt_trials = hpo.Trials()
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self._points_to_evaluate = 0
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else:
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assert isinstance(self._points_to_evaluate, (list, tuple))
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for i in range(len(self._points_to_evaluate)):
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config = self._points_to_evaluate[i]
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self._convert_categories_to_indices(config)
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# HyperOpt treats initial points as LIFO, reverse to get FIFO
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self._points_to_evaluate = list(reversed(self._points_to_evaluate))
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self._hpopt_trials = generate_trials_to_calculate(self._points_to_evaluate)
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self._hpopt_trials.refresh()
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self._points_to_evaluate = len(self._points_to_evaluate)
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self.domain = hpo.Domain(lambda spc: spc, self._space)
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def _convert_categories_to_indices(self, config) -> None:
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"""Convert config parameters for categories into hyperopt-compatible
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representations where instead the index of the category is expected."""
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def _lookup(config_dict, space_dict, key):
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if isinstance(config_dict[key], dict):
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for k in config_dict[key]:
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_lookup(config_dict[key], space_dict[key], k)
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else:
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if (
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key in space_dict
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and isinstance(space_dict[key], hpo.base.pyll.Apply)
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and space_dict[key].name == "switch"
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):
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if len(space_dict[key].pos_args) > 0:
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categories = [
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a.obj
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for a in space_dict[key].pos_args[1:]
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if a.name == "literal"
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]
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try:
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idx = categories.index(config_dict[key])
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except ValueError as exc:
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msg = (
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f"Did not find category with value "
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f"`{config_dict[key]}` in "
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f"hyperopt parameter `{key}`. "
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)
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if isinstance(config_dict[key], int):
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msg += (
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"In previous versions, a numerical "
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"index was expected for categorical "
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"values of `points_to_evaluate`, "
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"but in ray>=1.2.0, the categorical "
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"value is expected to be directly "
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"provided. "
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)
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msg += "Please make sure the specified category is valid."
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raise ValueError(msg) from exc
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config_dict[key] = idx
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for k in config:
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_lookup(config, self._space, k)
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def set_search_properties(
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self, metric: Optional[str], mode: Optional[str], config: Dict, **spec
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) -> bool:
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if self.domain:
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return False
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space = self.convert_search_space(config)
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self._space = space
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if metric:
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self._metric = metric
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if mode:
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self._mode = mode
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self.metric_op = -1.0 if self._mode == "max" else 1.0
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self._setup_hyperopt()
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return True
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def suggest(self, trial_id: str) -> Optional[Dict]:
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if not self.domain:
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raise RuntimeError(
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UNDEFINED_SEARCH_SPACE.format(
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cls=self.__class__.__name__, space="space"
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)
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+ HYPEROPT_UNDEFINED_DETAILS
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)
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if not self._metric or not self._mode:
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raise RuntimeError(
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UNDEFINED_METRIC_MODE.format(
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cls=self.__class__.__name__, metric=self._metric, mode=self._mode
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)
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)
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if self._points_to_evaluate > 0:
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using_point_to_evaluate = True
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new_trial = self._hpopt_trials.trials[self._points_to_evaluate - 1]
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self._points_to_evaluate -= 1
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else:
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using_point_to_evaluate = False
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new_ids = self._hpopt_trials.new_trial_ids(1)
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self._hpopt_trials.refresh()
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# Get new suggestion from Hyperopt
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new_trials = self.algo(
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new_ids,
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self.domain,
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self._hpopt_trials,
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self.rstate.randint(2**31 - 1),
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)
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self._hpopt_trials.insert_trial_docs(new_trials)
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self._hpopt_trials.refresh()
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new_trial = new_trials[0]
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self._live_trial_mapping[trial_id] = (new_trial["tid"], new_trial)
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# Taken from HyperOpt.base.evaluate
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config = hpo.base.spec_from_misc(new_trial["misc"])
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# We have to flatten nested spaces here so parameter names match
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config = flatten_dict(config, flatten_list=True)
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ctrl = hpo.base.Ctrl(self._hpopt_trials, current_trial=new_trial)
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memo = self.domain.memo_from_config(config)
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hpo.utils.use_obj_for_literal_in_memo(
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self.domain.expr, ctrl, hpo.base.Ctrl, memo
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)
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try:
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suggested_config = hpo.pyll.rec_eval(
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self.domain.expr,
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memo=memo,
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print_node_on_error=self.domain.rec_eval_print_node_on_error,
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)
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except (AssertionError, TypeError) as e:
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if using_point_to_evaluate and (
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isinstance(e, AssertionError) or "GarbageCollected" in str(e)
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):
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raise ValueError(
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"HyperOpt encountered a GarbageCollected switch argument. "
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"Usually this is caused by a config in "
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"`points_to_evaluate` "
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"missing a key present in `space`. Ensure that "
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"`points_to_evaluate` contains "
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"all non-constant keys from `space`.\n"
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"Config from `points_to_evaluate`: "
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f"{config}\n"
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"HyperOpt search space: "
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f"{self._space}"
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) from e
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raise e
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return copy.deepcopy(suggested_config)
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def on_trial_result(self, trial_id: str, result: Dict) -> None:
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ho_trial = self._get_hyperopt_trial(trial_id)
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if ho_trial is None:
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return
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now = hpo.utils.coarse_utcnow()
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ho_trial["book_time"] = now
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ho_trial["refresh_time"] = now
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def on_trial_complete(
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self, trial_id: str, result: Optional[Dict] = None, error: bool = False
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) -> None:
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"""Notification for the completion of trial.
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The result is internally negated when interacting with HyperOpt
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so that HyperOpt can "maximize" this value, as it minimizes on default.
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"""
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ho_trial = self._get_hyperopt_trial(trial_id)
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if ho_trial is None:
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return
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ho_trial["refresh_time"] = hpo.utils.coarse_utcnow()
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if error:
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ho_trial["state"] = hpo.base.JOB_STATE_ERROR
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ho_trial["misc"]["error"] = (str(TuneError), "Tune Error")
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self._hpopt_trials.refresh()
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elif result:
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self._process_result(trial_id, result)
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del self._live_trial_mapping[trial_id]
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def _process_result(self, trial_id: str, result: Dict) -> None:
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ho_trial = self._get_hyperopt_trial(trial_id)
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if not ho_trial:
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return
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ho_trial["refresh_time"] = hpo.utils.coarse_utcnow()
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ho_trial["state"] = hpo.base.JOB_STATE_DONE
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hp_result = self._to_hyperopt_result(result)
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ho_trial["result"] = hp_result
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self._hpopt_trials.refresh()
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def _to_hyperopt_result(self, result: Dict) -> Dict:
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try:
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return {"loss": self.metric_op * result[self.metric], "status": "ok"}
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except KeyError as e:
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raise RuntimeError(
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f"Hyperopt expected to see the metric `{self.metric}` in the "
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f"last result, but it was not found. To fix this, make "
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f"sure your call to `tune.report` or your return value of "
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f"your trainable class `step()` contains the above metric "
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f"as a key."
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) from e
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def _get_hyperopt_trial(self, trial_id: str) -> Optional[Dict]:
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if trial_id not in self._live_trial_mapping:
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return
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hyperopt_tid = self._live_trial_mapping[trial_id][0]
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return [t for t in self._hpopt_trials.trials if t["tid"] == hyperopt_tid][0]
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def get_state(self) -> Dict:
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return {
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"hyperopt_trials": self._hpopt_trials,
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"rstate": self.rstate.get_state(),
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}
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def set_state(self, state: Dict) -> None:
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self._hpopt_trials = state["hyperopt_trials"]
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self.rstate.set_state(state["rstate"])
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def save(self, checkpoint_path: str) -> None:
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save_object = self.__dict__.copy()
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save_object["__rstate"] = self.rstate.get_state()
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with open(checkpoint_path, "wb") as f:
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cloudpickle.dump(save_object, f)
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def restore(self, checkpoint_path: str) -> None:
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with open(checkpoint_path, "rb") as f:
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save_object = cloudpickle.load(f)
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if "__rstate" not in save_object:
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# Backwards compatibility
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self.set_state(save_object)
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else:
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self.rstate.set_state(save_object.pop("__rstate"))
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self.__dict__.update(save_object)
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@staticmethod
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def convert_search_space(spec: Dict, prefix: str = "") -> Dict:
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spec = copy.deepcopy(spec)
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resolved_vars, domain_vars, grid_vars = parse_spec_vars(spec)
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if not domain_vars and not grid_vars:
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return {}
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if grid_vars:
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raise ValueError(
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"Grid search parameters cannot be automatically converted "
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"to a HyperOpt search space."
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)
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def resolve_value(par: str, domain: Domain) -> Any:
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quantize = None
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sampler = domain.get_sampler()
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if isinstance(sampler, Quantized):
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quantize = sampler.q
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sampler = sampler.sampler
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if isinstance(domain, Float):
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if isinstance(sampler, LogUniform):
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if quantize:
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return hpo.hp.qloguniform(
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par, np.log(domain.lower), np.log(domain.upper), quantize
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)
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return hpo.hp.loguniform(
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par, np.log(domain.lower), np.log(domain.upper)
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)
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elif isinstance(sampler, Uniform):
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if quantize:
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return hpo.hp.quniform(
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par, domain.lower, domain.upper, quantize
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)
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return hpo.hp.uniform(par, domain.lower, domain.upper)
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elif isinstance(sampler, Normal):
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if quantize:
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return hpo.hp.qnormal(par, sampler.mean, sampler.sd, quantize)
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return hpo.hp.normal(par, sampler.mean, sampler.sd)
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elif isinstance(domain, Integer):
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if isinstance(sampler, LogUniform):
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if quantize:
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return hpo.base.pyll.scope.int(
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hpo.hp.qloguniform(
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par,
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np.log(domain.lower),
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np.log(domain.upper),
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quantize,
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)
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)
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return hpo.base.pyll.scope.int(
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hpo.hp.qloguniform(
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par, np.log(domain.lower), np.log(domain.upper - 1), 1.0
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)
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)
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elif isinstance(sampler, Uniform):
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if quantize:
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return hpo.base.pyll.scope.int(
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hpo.hp.quniform(
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par, domain.lower, domain.upper - 1, quantize
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)
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)
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|
return hpo.hp.uniformint(par, domain.lower, high=domain.upper - 1)
|
|
elif isinstance(domain, Categorical):
|
|
if isinstance(sampler, Uniform):
|
|
return hpo.hp.choice(
|
|
par,
|
|
[
|
|
(
|
|
HyperOptSearch.convert_search_space(
|
|
category, prefix=par
|
|
)
|
|
if isinstance(category, dict)
|
|
else (
|
|
HyperOptSearch.convert_search_space(
|
|
dict(enumerate(category)), prefix=f"{par}/{i}"
|
|
)
|
|
if isinstance(category, list)
|
|
and len(category) > 0
|
|
and isinstance(category[0], Domain)
|
|
else (
|
|
resolve_value(f"{par}/{i}", category)
|
|
if isinstance(category, Domain)
|
|
else category
|
|
)
|
|
)
|
|
)
|
|
for i, category in enumerate(domain.categories)
|
|
],
|
|
)
|
|
|
|
raise ValueError(
|
|
"HyperOpt does not support parameters of type "
|
|
"`{}` with samplers of type `{}`".format(
|
|
type(domain).__name__, type(domain.sampler).__name__
|
|
)
|
|
)
|
|
|
|
for path, domain in domain_vars:
|
|
par = "/".join([str(p) for p in ((prefix,) + path if prefix else path)])
|
|
value = resolve_value(par, domain)
|
|
assign_value(spec, path, value)
|
|
|
|
return spec
|