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PSO/pso/particle.py
jung-geun 8012cf3557 23-05-31
전체 파티클 중 일부를 현재 속도의 음수 방향으로 진행하도록 하여 지역해에 갇혀 조기수렴하는 문제의 방안으로 사용
2023-05-31 02:52:32 +09:00

126 lines
4.5 KiB
Python

import tensorflow as tf
from tensorflow import keras
# import cupy as cp
import numpy as np
class Particle:
def __init__(self, model:keras.models, loss, random:bool = False):
self.model = model
self.loss = loss
self.init_weights = self.model.get_weights()
i_w_,s_,l_ = self._encode(self.init_weights)
i_w_ = np.random.rand(len(i_w_)) / 5 - 0.10
self.velocities = self._decode(i_w_,s_,l_)
self.random = random
self.best_score = 0
self.best_weights = self.init_weights
"""
Returns:
(cupy array) : 가중치 - 1차원으로 풀어서 반환
(list) : 가중치의 원본 shape
(list) : 가중치의 원본 shape의 길이
"""
def _encode(self, weights:list):
# w_gpu = cp.array([])
w_gpu = np.array([])
lenght = []
shape = []
for layer in weights:
shape.append(layer.shape)
w_ = layer.reshape(-1)
lenght.append(len(w_))
# w_gpu = cp.append(w_gpu, w_)
w_gpu = np.append(w_gpu, w_)
return w_gpu, shape, lenght
"""
Returns:
(list) : 가중치 원본 shape으로 복원
"""
def _decode(self, weight:list, shape, lenght):
weights = []
start = 0
for i in range(len(shape)):
end = start + lenght[i]
w_ = weight[start:end]
# w_ = weight[start:end].get()
w_ = np.reshape(w_, shape[i])
# w_ = w_.reshape(shape[i])
weights.append(w_)
start = end
return weights
def get_score(self, x, y, renewal:str = "acc"):
self.model.compile(loss=self.loss, optimizer="sgd", metrics=["accuracy"])
score = self.model.evaluate(x, y, verbose=0)
# print(score)
if renewal == "acc":
if score[1] > self.best_score:
self.best_score = score[1]
self.best_weights = self.model.get_weights()
elif renewal == "loss":
if score[0] < self.best_score:
self.best_score = score[0]
self.best_weights = self.model.get_weights()
return score
def _update_velocity(self, local_rate, global_rate, w, g_best):
encode_w, w_sh, w_len = self._encode(weights = self.model.get_weights())
encode_v, _, _ = self._encode(weights = self.velocities)
encode_p, _, _ = self._encode(weights = self.best_weights)
encode_g, _, _ = self._encode(weights = g_best)
r0 = np.random.rand()
r1 = np.random.rand()
new_v = w * encode_v + local_rate * r0 * (encode_p - encode_w) + global_rate * r1 * (encode_g - encode_w)
self.velocities = self._decode(new_v, w_sh, w_len)
def _update_velocity_w(self, local_rate, global_rate, w, w_p, w_g, g_best):
encode_w, w_sh, w_len = self._encode(weights = self.model.get_weights())
encode_v, _, _ = self._encode(weights = self.velocities)
encode_p, _, _ = self._encode(weights = self.best_weights)
encode_g, _, _ = self._encode(weights = g_best)
r0 = np.random.rand()
r1 = np.random.rand()
new_v = w * encode_v + local_rate * r0 * (w_p * encode_p - encode_w) + global_rate * r1 * (w_g * encode_g - encode_w)
self.velocities = self._decode(new_v, w_sh, w_len)
def _update_weights(self):
encode_w, w_sh, w_len = self._encode(weights = self.model.get_weights())
encode_v, _, _ = self._encode(weights = self.velocities)
if self.random:
encode_v = -1 * encode_v
new_w = encode_w + encode_v
self.model.set_weights(self._decode(new_w, w_sh, w_len))
def f(self, x, y, weights):
self.model.set_weights(weights)
score = self.model.evaluate(x, y, verbose = 0)[1]
if score > 0:
return 1 / (1 + score)
else:
return 1 + np.abs(score)
def step(self, x, y, local_rate, global_rate, w, g_best, renewal:str = "acc"):
self._update_velocity(local_rate, global_rate, w, g_best)
self._update_weights()
return self.get_score(x, y, renewal)
def step_w(self, x, y, local_rate, global_rate, w, g_best, w_p, w_g, renewal:str = "acc"):
self._update_velocity_w(local_rate, global_rate, w, w_p, w_g, g_best)
self._update_weights()
return self.get_score(x, y, renewal)
def get_best_score(self):
return self.best_score
def get_best_weights(self):
return self.best_weights