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# Author: Simon Blanke |
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# Email: [email protected] |
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# License: MIT License |
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import numpy as np |
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from sklearn.neighbors import KernelDensity |
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from ...base_optimizer import BaseOptimizer |
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from ...base_positioner import BasePositioner |
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class TreeStructuredParzenEstimators(BaseOptimizer): |
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def __init__(self, _main_args_, _opt_args_): |
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super().__init__(_main_args_, _opt_args_) |
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self.kd_best = KernelDensity() |
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self.kd_worst = KernelDensity() |
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def _get_samples(self): |
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n_samples = self.X_sample.shape[0] |
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n_best = int(n_samples * self._opt_args_.gamme_tpe) |
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Y_sample = self.Y_sample[:, 0] |
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index_best = Y_sample.argsort()[-n_best:][::-1] |
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best_samples = self.X_sample[index_best] |
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worst_samples = self.X_sample[~index_best] |
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return best_samples, worst_samples |
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def _all_possible_pos(self, cand): |
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pos_space = [] |
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for dim_ in cand._space_.dim: |
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pos_space.append(np.arange(dim_ + 1)) |
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self.n_dim = len(pos_space) |
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self.all_pos_comb = np.array(np.meshgrid(*pos_space)).T.reshape(-1, self.n_dim) |
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def expected_improvement(self): |
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logprob_best = self.kd_best.score_samples(self.all_pos_comb) |
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logprob_worst = self.kd_worst.score_samples(self.all_pos_comb) |
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prob_best = np.exp(logprob_best) |
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prob_worst = np.exp(logprob_worst) |
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return np.divide( |
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prob_best, prob_worst, out=np.zeros_like(prob_worst), where=prob_worst != 0 |
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) |
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def propose_location(self, cand): |
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best_samples, worst_samples = self._get_samples() |
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self.kd_best.fit(best_samples) |
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self.kd_worst.fit(worst_samples) |
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exp_imp = self.expected_improvement() |
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index_best = list(exp_imp.argsort()[::-1]) |
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all_pos_comb_sorted = self.all_pos_comb[index_best] |
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pos_best = all_pos_comb_sorted[0] |
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return pos_best |
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def _iterate(self, i, _cand_, _p_): |
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if i < self._opt_args_.start_up_evals: |
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_p_.pos_new = _p_.move_random(_cand_) |
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_p_.score_new = _cand_.eval_pos(_p_.pos_new) |
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else: |
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_p_.pos_new = self.propose_location(_cand_) |
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_p_.score_new = _cand_.eval_pos(_p_.pos_new) |
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if _p_.score_new > _cand_.score_best: |
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_cand_, _p_ = self._update_pos(_cand_, _p_) |
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self.X_sample = np.vstack((self.X_sample, _p_.pos_new)) |
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self.Y_sample = np.vstack((self.Y_sample, _p_.score_new)) |
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return _cand_ |
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View Code Duplication |
def _init_opt_positioner(self, _cand_): |
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_p_ = Bayesian() |
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self._all_possible_pos(_cand_) |
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if self._opt_args_.warm_start_smbo: |
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self.X_sample = _cand_.mem._get_para() |
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self.Y_sample = _cand_.mem._get_score() |
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else: |
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self.X_sample = _cand_.pos_best.reshape(1, -1) |
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self.Y_sample = np.array(_cand_.score_best).reshape(1, -1) |
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_p_.pos_current = _cand_.pos_best |
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_p_.score_current = _cand_.score_best |
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return _p_ |
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class Bayesian(BasePositioner): |
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def __init__(self, *args, **kwargs): |
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super().__init__(*args, **kwargs) |
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