要求使用python语言编写一个遗传算法,将一个4*8的二维矩阵进行DCT编码,压缩成2*4的dtc矩阵,要求矩阵内的值限制在-1到1之间,对压缩后矩阵进行优化,在适应度评估时将该矩阵逆变换回4*8的矩阵,目标函数是4*8矩阵的每一列的和分别等于45.2,46.4,47.6,48.8,50,51.2,52.4,53.6。请给出实现上述步骤的代码,并请注意,4*8的矩阵内的值均在-1.3到1.5之间
时间: 2023-11-27 10:55:16 浏览: 60
以下是一个基于Python的遗传算法实现,用于将4x8的矩阵进行DCT编码,并将其压缩为2x4的DTC矩阵,并在适应度评估时将其逆变换回原始矩阵,然后根据给定的约束条件对矩阵进行优化。
```python
import numpy as np
import random
# 定义常量
POPULATION_SIZE = 30
CROSSOVER_RATE = 0.8
MUTATION_RATE = 0.03
NUM_GENERATIONS = 1000
NUM_PARENTS = 2
NUM_BITS = 3
# 定义DCT矩阵
DCT_MATRIX = np.array([
[0.3536, 0.3536, 0.3536, 0.3536, 0.3536, 0.3536, 0.3536, 0.3536],
[0.4904, 0.4157, 0.2778, 0.0975, -0.0975, -0.2778, -0.4157, -0.4904],
[0.4619, 0.1913, -0.1913, -0.4619, -0.4619, -0.1913, 0.1913, 0.4619],
[0.4157, -0.0975, -0.4904, -0.2778, 0.2778, 0.4904, 0.0975, -0.4157]
])
# 定义逆DCT矩阵
IDCT_MATRIX = np.transpose(DCT_MATRIX)
# 定义目标列和
TARGET_COLUMN_SUMS = [45.2, 46.4, 47.6, 48.8, 50.0, 51.2, 52.4, 53.6]
# 定义矩阵的范围
MIN_VALUE = -1.3
MAX_VALUE = 1.5
def dct_4x8(matrix):
"""对4x8矩阵进行DCT编码"""
return np.dot(DCT_MATRIX, matrix)
def idct_4x8(matrix):
"""对DCT编码后的2x4矩阵进行逆DCT变换"""
return np.dot(IDCT_MATRIX, matrix)
def normalize(matrix):
"""将矩阵的值限制在MIN_VALUE和MAX_VALUE之间"""
return np.clip(matrix, MIN_VALUE, MAX_VALUE)
def fitness(matrix):
"""计算矩阵的适应度"""
decoded_matrix = idct_4x8(matrix)
column_sums = np.sum(decoded_matrix, axis=0)
# 计算每一列与目标列和的差异
diff = np.abs(column_sums - TARGET_COLUMN_SUMS)
return np.sum(diff)
def crossover(parent1, parent2):
"""交叉操作"""
crossover_point = random.randint(1, 7)
child1 = np.concatenate((parent1[:crossover_point, :], parent2[crossover_point:, :]), axis=0)
child2 = np.concatenate((parent2[:crossover_point, :], parent1[crossover_point:, :]), axis=0)
return child1, child2
def mutation(matrix):
"""突变操作"""
for i in range(matrix.shape[0]):
for j in range(matrix.shape[1]):
if random.random() < MUTATION_RATE:
# 在MIN_VALUE和MAX_VALUE之间随机生成一个值
matrix[i, j] = random.uniform(MIN_VALUE, MAX_VALUE)
return matrix
def select_parents(population):
"""选择父代"""
parents = []
for i in range(NUM_PARENTS):
# 选择适应度最佳的个体
best_fitness = None
best_individual = None
for individual in population:
if best_fitness is None or fitness(individual) < best_fitness:
best_fitness = fitness(individual)
best_individual = individual
parents.append(best_individual)
# 将已选择的个体从种群中删除
population.remove(best_individual)
return parents
def generate_initial_population():
"""生成初始种群"""
population = []
for i in range(POPULATION_SIZE):
# 在MIN_VALUE和MAX_VALUE之间随机生成一个4x8矩阵
matrix = np.random.uniform(MIN_VALUE, MAX_VALUE, size=(4, 8))
# 对矩阵进行DCT编码并将其压缩为2x4
compressed_matrix = dct_4x8(matrix)[:2, :]
# 将矩阵的值限制在MIN_VALUE和MAX_VALUE之间
normalized_matrix = normalize(compressed_matrix)
population.append(normalized_matrix)
return population
def run_ga():
"""运行遗传算法"""
population = generate_initial_population()
for generation in range(NUM_GENERATIONS):
# 选择父代
parents = select_parents(population)
next_population = []
while len(next_population) < POPULATION_SIZE:
# 随机选择两个父代进行交叉操作
parent1, parent2 = random.sample(parents, 2)
child1, child2 = crossover(parent1, parent2)
# 对交叉后的子代进行突变操作
mutated_child1 = mutation(child1)
mutated_child2 = mutation(child2)
# 将子代加入下一代种群中
next_population.append(mutated_child1)
next_population.append(mutated_child2)
population = next_population
# 选择适应度最佳的个体并返回其解码后的矩阵
best_fitness = None
best_individual = None
for individual in population:
if best_fitness is None or fitness(individual) < best_fitness:
best_fitness = fitness(individual)
best_individual = individual
decoded_matrix = idct_4x8(best_individual)
return decoded_matrix
if __name__ == '__main__':
result = run_ga()
print(result)
```
该代码生成初始种群,然后在每个代中选择适应度最佳的个体,使用交叉和突变操作生成新的个体,并重复此过程直到达到指定的迭代次数。最后,选择适应度最佳的个体并返回其解码后的矩阵。
注意,这个实现仅用于教学目的,实际上并不是最优的遗传算法实现。在实际应用中,需要对各个参数进行调整以获得更好的结果。
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