Source code for

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

    import ax
except ImportError:
    ax = None
import logging

from ray.tune.suggest.suggestion import SuggestionAlgorithm

logger = logging.getLogger(__name__)

[docs]class AxSearch(SuggestionAlgorithm): """A wrapper around Ax to provide trial suggestions. Requires Ax to be installed. Ax is an open source tool from Facebook for configuring and optimizing experiments. More information can be found in Parameters: parameters (list[dict]): Parameters in the experiment search space. Required elements in the dictionaries are: "name" (name of this parameter, string), "type" (type of the parameter: "range", "fixed", or "choice", string), "bounds" for range parameters (list of two values, lower bound first), "values" for choice parameters (list of values), and "value" for fixed parameters (single value). objective_name (str): Name of the metric used as objective in this experiment. This metric must be present in `raw_data` argument to `log_data`. This metric must also be present in the dict reported/returned by the Trainable. max_concurrent (int): Number of maximum concurrent trials. Defaults to 10. minimize (bool): Whether this experiment represents a minimization problem. Defaults to False. parameter_constraints (list[str]): Parameter constraints, such as "x3 >= x4" or "x3 + x4 >= 2". outcome_constraints (list[str]): Outcome constraints of form "metric_name >= bound", like "m1 <= 3." use_early_stopped_trials (bool): Whether to use early terminated trial results in the optimization process. Example: >>> parameters = [ >>> {"name": "x1", "type": "range", "bounds": [0.0, 1.0]}, >>> {"name": "x2", "type": "range", "bounds": [0.0, 1.0]}, >>> ] >>> algo = AxSearch(parameters=parameters, >>> objective_name="hartmann6", max_concurrent=4) """ def __init__(self, ax_client, max_concurrent=10, **kwargs): assert ax is not None, "Ax must be installed!" assert type(max_concurrent) is int and max_concurrent > 0 self._ax = ax_client exp = self._ax.experiment self._objective_name = if self._ax._enforce_sequential_optimization: logger.warning("Detected sequential enforcement. Setting max " "concurrency to 1.") max_concurrent = 1 self._max_concurrent = max_concurrent self._parameters = list(exp.parameters) self._live_index_mapping = {} super(AxSearch, self).__init__(**kwargs) def _suggest(self, trial_id): if self._num_live_trials() >= self._max_concurrent: return None parameters, trial_index = self._ax.get_next_trial() self._live_index_mapping[trial_id] = trial_index return parameters def on_trial_result(self, trial_id, result): pass def on_trial_complete(self, trial_id, result=None, error=False, early_terminated=False): """Notification for the completion of trial. Data of form key value dictionary of metric names and values. """ if result: self._process_result(trial_id, result, early_terminated) self._live_index_mapping.pop(trial_id) def _process_result(self, trial_id, result, early_terminated=False): if early_terminated and self._use_early_stopped is False: return ax_trial_index = self._live_index_mapping[trial_id] metric_dict = { self._objective_name: (result[self._objective_name], 0.0) } outcome_names = [ for oc in self._ax.experiment.optimization_config.outcome_constraints ] metric_dict.update({on: (result[on], 0.0) for on in outcome_names}) self._ax.complete_trial( trial_index=ax_trial_index, raw_data=metric_dict) def _num_live_trials(self): return len(self._live_index_mapping)