能给出MapReduce实现粒子群算法的代码吗
时间: 2024-05-11 16:17:18 浏览: 19
以下是一个简单的MapReduce实现粒子群算法的代码示例,仅供参考:
Mapper函数:
```python
def mapper(key, value):
# 将输入的粒子向量解析成向量和适应度
particle, fitness = value.split(',')
particle = list(map(float, particle.split()))
fitness = float(fitness)
# 计算粒子的新速度和位置
new_velocity = []
new_position = []
for i in range(len(particle)):
# 计算粒子的速度
rand_1 = random.uniform(0, 1)
rand_2 = random.uniform(0, 1)
new_velocity.append(0.5 * particle[i] + 1.0 * rand_1 * (best_global[i] - particle[i]) + 1.0 * rand_2 * (best_local[i] - particle[i]))
# 计算粒子的位置
new_position.append(particle[i] + new_velocity[i])
# 输出新的粒子向量和适应度
output_key = ','.join(map(str, new_position))
output_value = str(calculate_fitness(new_position))
yield output_key, output_value
```
Reducer函数:
```python
def reducer(key, values):
# 选择适应度最好的粒子作为本地最优解
best_local_fitness = float('inf')
best_local_particle = None
for value in values:
fitness = float(value)
if fitness < best_local_fitness:
best_local_fitness = fitness
best_local_particle = key.split(',')
best_local_particle = list(map(float, best_local_particle))
# 更新全局最优解
global best_global_fitness
global best_global_particle
if best_local_fitness < best_global_fitness:
best_global_fitness = best_local_fitness
best_global_particle = best_local_particle
# 输出结果
output_key = ','.join(map(str, best_local_particle))
output_value = str(best_local_fitness)
yield output_key, output_value
```
请注意,此代码示例仅仅是一个非常简单的MapReduce实现粒子群算法的例子,实际应用中还需要更多的优化和改进。
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