# -*- coding: utf-8 -*-
"""
:mod:`orion.algo.random` -- Random sampler as optimization algorithm
======================================================================
.. module:: random
:platform: Unix
:synopsis: Draw and deliver samples from prior defined in problem's domain.
"""
import numpy
from orion.algo.base import BaseAlgorithm, infer_trial_id
[docs]class Random(BaseAlgorithm):
"""Implement a algorithm that samples randomly from the problem's space."""
def __init__(self, space, seed=None):
"""Random sampler takes no other hyperparameter than the problem's space
itself.
:param space: `orion.algo.space.Space` of optimization.
:param seed: Integer seed for the random number generator.
"""
super(Random, self).__init__(space, seed=seed)
[docs] def seed_rng(self, seed):
"""Seed the state of the random number generator.
:param seed: Integer seed for the random number generator.
"""
self.rng = numpy.random.RandomState(seed)
@property
def state_dict(self):
"""Return a state dict that can be used to reset the state of the algorithm."""
_state_dict = super(Random, self).state_dict
_state_dict['rng_state'] = self.rng.get_state()
return _state_dict
[docs] def set_state(self, state_dict):
"""Reset the state of the algorithm based on the given state_dict
:param state_dict: Dictionary representing state of an algorithm
"""
super(Random, self).set_state(state_dict)
self.seed_rng(0)
self.rng.set_state(state_dict['rng_state'])
[docs] def suggest(self, num=1):
"""Suggest a `num` of new sets of parameters. Randomly draw samples
from the import space and return them.
:param num: how many sets to be suggested.
.. note:: New parameters must be compliant with the problem's domain
`orion.algo.space.Space`.
"""
points = []
point_ids = set(self._trials_info.keys())
i = 0
while len(points) < num:
new_point = self.space.sample(1, seed=tuple(self.rng.randint(0, 1000000, size=3)))[0]
point_id = infer_trial_id(new_point)
if point_id not in point_ids:
point_ids.add(point_id)
points.append(new_point)
i += 1
return points