gradient_free_optimizers.optimizers.local_opt.downhill_simplex.DownhillSimplexOptimizer.iterate() - Code Metrics - SimonBlanke/Gradient-Free-Optimizers - Measure and Improve Code Quality continuously with Scrutinizer

DownhillSimplexOptimizer.iterate() B
last analyzed 2025-08-06 16:49 UTC

↳ Parent: gradient_free_optimizers.optimizers.local_opt.downhill_simplex

Complexity

Conditions

Size

Total Lines	59
Code Lines	39

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
eloc	39
dl	0
loc	59
rs	7.544
c	0
b	0
f	0
cc	7
nop	1

How to fix Long Method

# Author: Simon Blanke
# Email: [email protected]
# License: MIT License


import random
import numpy as np

from .hill_climbing_optimizer import HillClimbingOptimizer


def sort_list_idx(list_):
    list_np = np.array(list_)
    idx_sorted = list(list_np.argsort()[::-1])
    return idx_sorted


def centeroid(array_list):

    centeroid = []

    for idx in range(array_list[0].shape[0]):
        center_dim_pos = []
        for array in array_list:
            center_dim_pos.append(array[idx])

        center_dim_mean = np.array(center_dim_pos).mean()
        centeroid.append(center_dim_mean)

    return centeroid


class DownhillSimplexOptimizer(HillClimbingOptimizer):
    name = "Downhill Simplex"
    _name_ = "downhill_simplex"
    __name__ = "DownhillSimplexOptimizer"

    optimizer_type = "local"
    computationally_expensive = False

    def __init__(
        self,
        search_space,
        initialize={"grid": 4, "random": 2, "vertices": 4},
        constraints=[],
        random_state=None,
        rand_rest_p=0,
        nth_process=None,
        alpha=1,
        gamma=2,
        beta=0.5,
        sigma=0.5,
    ):
        super().__init__(
            search_space=search_space,
            initialize=initialize,
            constraints=constraints,
            random_state=random_state,
            rand_rest_p=rand_rest_p,
            nth_process=nth_process,
        )

        self.alpha = alpha
        self.gamma = gamma
        self.beta = beta
        self.sigma = sigma

        self.n_simp_positions = len(self.conv.search_space) + 1
        self.simp_positions = []

        self.simplex_step = 0

        diff_init = self.n_simp_positions - self.init.n_inits
        if diff_init > 0:
            self.init.add_n_random_init_pos(diff_init)

    def finish_initialization(self):
        idx_sorted = sort_list_idx(self.scores_valid)
        self.simplex_pos = [self.positions_valid[idx] for idx in idx_sorted]
        self.simplex_scores = [self.scores_valid[idx] for idx in idx_sorted]

        self.simplex_step = 1

        self.i_x_0 = 0
        self.i_x_N_1 = -2
        self.i_x_N = -1

        self.search_state = "iter"

    @HillClimbingOptimizer.track_new_pos
    def iterate(self):
        simplex_stale = all(
            [
                np.array_equal(self.simplex_pos[0], array)
                for array in self.simplex_pos
            ]
        )

        if simplex_stale:
            idx_sorted = sort_list_idx(self.scores_valid)
            self.simplex_pos = [self.positions_valid[idx] for idx in idx_sorted]
            self.simplex_scores = [self.scores_valid[idx] for idx in idx_sorted]

            self.simplex_step = 1

        if self.simplex_step == 1:
            idx_sorted = sort_list_idx(self.simplex_scores)
            self.simplex_pos = [self.simplex_pos[idx] for idx in idx_sorted]
            self.simplex_scores = [
                self.simplex_scores[idx] for idx in idx_sorted
            ]

            self.center_array = centeroid(self.simplex_pos[:-1])

            r_pos = self.center_array + self.alpha * (
                self.center_array - self.simplex_pos[-1]
            )
            self.r_pos = self.conv2pos(r_pos)
            pos_new = self.r_pos

        elif self.simplex_step == 2:
            e_pos = self.center_array + self.gamma * (
                self.center_array - self.simplex_pos[-1]
            )
            self.e_pos = self.conv2pos(e_pos)
            self.simplex_step = 1

            pos_new = self.e_pos

        elif self.simplex_step == 3:
            # iter Contraction
            c_pos = self.h_pos + self.beta * (self.center_array - self.h_pos)
            c_pos = self.conv2pos(c_pos)

            pos_new = c_pos

        elif self.simplex_step == 4:
            # iter Shrink
            pos = self.simplex_pos[self.compress_idx]
            pos = pos + self.sigma * (self.simplex_pos[0] - pos)

            pos_new = self.conv2pos(pos)

        if self.conv.not_in_constraint(pos_new):

            return pos_new

        return self.move_climb(
            pos_new, epsilon=self.epsilon, distribution=self.distribution
        )

    @HillClimbingOptimizer.track_new_score
    def evaluate(self, score_new):
        if self.simplex_step != 0:
            self.prev_pos = self.positions_valid[-1]

        if self.simplex_step == 1:
            # self.r_pos = self.prev_pos
            self.r_score = score_new

            if self.r_score > self.simplex_scores[0]:
                self.simplex_step = 2

            elif self.r_score > self.simplex_scores[-2]:
                # if r is better than x N-1
                self.simplex_pos[-1] = self.r_pos
                self.simplex_scores[-1] = self.r_score
                self.simplex_step = 1

            if self.simplex_scores[-1] > self.r_score:
                self.h_pos = self.simplex_pos[-1]
                self.h_score = self.simplex_scores[-1]
            else:
                self.h_pos = self.r_pos
                self.h_score = self.r_score

            self.simplex_step = 3

        elif self.simplex_step == 2:
            self.e_score = score_new

            if self.e_score > self.r_score:
                self.simplex_scores[-1] = self.e_pos
            elif self.r_score > self.e_score:
                self.simplex_scores[-1] = self.r_pos
            else:
                self.simplex_scores[-1] = random.choice(
                    [self.e_pos, self.r_pos]
                )[0]

        elif self.simplex_step == 3:
            # eval Contraction
            self.c_pos = self.prev_pos
            self.c_score = score_new

            if self.c_score > self.simplex_scores[-1]:
                self.simplex_scores[-1] = self.c_score
                self.simplex_pos[-1] = self.c_pos

                self.simplex_step = 1

            else:
                # start Shrink
                self.simplex_step = 4
                self.compress_idx = 0

        elif self.simplex_step == 4:
            # eval Shrink
            self.simplex_scores[self.compress_idx] = score_new
            self.simplex_pos[self.compress_idx] = self.prev_pos

            self.compress_idx += 1

            if self.compress_idx == self.n_simp_positions:
                self.simplex_step = 1


1		# Author: Simon Blanke
2		# Email: [email protected]
3		# License: MIT License
4
5
6		import random
7		import numpy as np
8
9		from .hill_climbing_optimizer import HillClimbingOptimizer
10
11
12		def sort_list_idx(list_):
13		list_np = np.array(list_)
14		idx_sorted = list(list_np.argsort()[::-1])
15		return idx_sorted
16
17
18	View Code Duplication	def centeroid(array_list):
		0 ignored issues – show Duplication introduced 2022-08-17 15:28 UTC by Report Bug Copy Issue Report This code seems to be duplicated in your project. Loading history...
19		centeroid = []
20
21		for idx in range(array_list[0].shape[0]):
22		center_dim_pos = []
23		for array in array_list:
24		center_dim_pos.append(array[idx])
25
26		center_dim_mean = np.array(center_dim_pos).mean()
27		centeroid.append(center_dim_mean)
28
29		return centeroid
30
31
32		class DownhillSimplexOptimizer(HillClimbingOptimizer):
33		name = "Downhill Simplex"
34		_name_ = "downhill_simplex"
35		__name__ = "DownhillSimplexOptimizer"
36
37		optimizer_type = "local"
38		computationally_expensive = False
39
40		def __init__(
41		self,
42		search_space,
43		initialize={"grid": 4, "random": 2, "vertices": 4},
44		constraints=[],
45		random_state=None,
46		rand_rest_p=0,
47		nth_process=None,
48		alpha=1,
49		gamma=2,
50		beta=0.5,
51		sigma=0.5,
52		):
53		super().__init__(
54		search_space=search_space,
55		initialize=initialize,
56		constraints=constraints,
57		random_state=random_state,
58		rand_rest_p=rand_rest_p,
59		nth_process=nth_process,
60		)
61
62		self.alpha = alpha
63		self.gamma = gamma
64		self.beta = beta
65		self.sigma = sigma
66
67		self.n_simp_positions = len(self.conv.search_space) + 1
68		self.simp_positions = []
69
70		self.simplex_step = 0
71
72		diff_init = self.n_simp_positions - self.init.n_inits
73		if diff_init > 0:
74		self.init.add_n_random_init_pos(diff_init)
75
76		def finish_initialization(self):
77		idx_sorted = sort_list_idx(self.scores_valid)
78		self.simplex_pos = [self.positions_valid[idx] for idx in idx_sorted]
79		self.simplex_scores = [self.scores_valid[idx] for idx in idx_sorted]
80
81		self.simplex_step = 1
82
83		self.i_x_0 = 0
84		self.i_x_N_1 = -2
85		self.i_x_N = -1
86
87		self.search_state = "iter"
88
89		@HillClimbingOptimizer.track_new_pos
90		def iterate(self):
91		simplex_stale = all(
92		[
93		np.array_equal(self.simplex_pos[0], array)
94		for array in self.simplex_pos
95		]
96		)
97
98		if simplex_stale:
99		idx_sorted = sort_list_idx(self.scores_valid)
100		self.simplex_pos = [self.positions_valid[idx] for idx in idx_sorted]
101		self.simplex_scores = [self.scores_valid[idx] for idx in idx_sorted]
102
103		self.simplex_step = 1
104
105		if self.simplex_step == 1:
106		idx_sorted = sort_list_idx(self.simplex_scores)
107		self.simplex_pos = [self.simplex_pos[idx] for idx in idx_sorted]
108		self.simplex_scores = [
109		self.simplex_scores[idx] for idx in idx_sorted
110		]
111
112		self.center_array = centeroid(self.simplex_pos[:-1])
113
114		r_pos = self.center_array + self.alpha * (
115		self.center_array - self.simplex_pos[-1]
116		)
117		self.r_pos = self.conv2pos(r_pos)
118		pos_new = self.r_pos
119
120		elif self.simplex_step == 2:
121		e_pos = self.center_array + self.gamma * (
122		self.center_array - self.simplex_pos[-1]
123		)
124		self.e_pos = self.conv2pos(e_pos)
125		self.simplex_step = 1
126
127		pos_new = self.e_pos
128
129		elif self.simplex_step == 3:
130		# iter Contraction
131		c_pos = self.h_pos + self.beta * (self.center_array - self.h_pos)
132		c_pos = self.conv2pos(c_pos)
133
134		pos_new = c_pos
135
136		elif self.simplex_step == 4:
137		# iter Shrink
138		pos = self.simplex_pos[self.compress_idx]
139		pos = pos + self.sigma * (self.simplex_pos[0] - pos)
140
141		pos_new = self.conv2pos(pos)
142
143		if self.conv.not_in_constraint(pos_new):
		0 ignored issues – show introduced 2023-04-11 08:42 UTC by Report Bug Copy Issue Report The variable `pos_new` does not seem to be defined for all execution paths. Loading history...
144		return pos_new
145
146		return self.move_climb(
147		pos_new, epsilon=self.epsilon, distribution=self.distribution
148		)
149
150		@HillClimbingOptimizer.track_new_score
151		def evaluate(self, score_new):
152		if self.simplex_step != 0:
153		self.prev_pos = self.positions_valid[-1]
154
155		if self.simplex_step == 1:
156		# self.r_pos = self.prev_pos
157		self.r_score = score_new
158
159		if self.r_score > self.simplex_scores[0]:
160		self.simplex_step = 2
161
162		elif self.r_score > self.simplex_scores[-2]:
163		# if r is better than x N-1
164		self.simplex_pos[-1] = self.r_pos
165		self.simplex_scores[-1] = self.r_score
166		self.simplex_step = 1
167
168		if self.simplex_scores[-1] > self.r_score:
169		self.h_pos = self.simplex_pos[-1]
170		self.h_score = self.simplex_scores[-1]
171		else:
172		self.h_pos = self.r_pos
173		self.h_score = self.r_score
174
175		self.simplex_step = 3
176
177		elif self.simplex_step == 2:
178		self.e_score = score_new
179
180		if self.e_score > self.r_score:
181		self.simplex_scores[-1] = self.e_pos
182		elif self.r_score > self.e_score:
183		self.simplex_scores[-1] = self.r_pos
184		else:
185		self.simplex_scores[-1] = random.choice(
186		[self.e_pos, self.r_pos]
187		)[0]
188
189		elif self.simplex_step == 3:
190		# eval Contraction
191		self.c_pos = self.prev_pos
192		self.c_score = score_new
193
194		if self.c_score > self.simplex_scores[-1]:
195		self.simplex_scores[-1] = self.c_score
196		self.simplex_pos[-1] = self.c_pos
197
198		self.simplex_step = 1
199
200		else:
201		# start Shrink
202		self.simplex_step = 4
203		self.compress_idx = 0
204
205		elif self.simplex_step == 4:
206		# eval Shrink
207		self.simplex_scores[self.compress_idx] = score_new
208		self.simplex_pos[self.compress_idx] = self.prev_pos
209
210		self.compress_idx += 1
211
212		if self.compress_idx == self.n_simp_positions:
213		self.simplex_step = 1
214

SimonBlanke / Gradient-Free-Optimizers

DownhillSimplexOptimizer.iterate() B last analyzed 2025-08-06 16:49 UTC

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DownhillSimplexOptimizer.iterate() B
last analyzed 2025-08-06 16:49 UTC