HPCC2025/greedy_solver.py

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Python
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2025-03-12 11:33:35 +08:00
import math
import yaml
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import numpy as np
def calculate_max_photos_per_flight(params):
"""计算每次飞行能拍摄的最大照片数量
基于以下约束
1. 电池能量约束
2. 计算+传输时间 = 飞行时间
"""
# 从参数中提取时间和能量因子
flight_time_factor = params['flight_time_factor']
comp_time_factor = params['comp_time_factor']
trans_time_factor = params['trans_time_factor']
battery_energy_capacity = params['battery_energy_capacity']
flight_energy_factor = params['flight_energy_factor']
comp_energy_factor = params['comp_energy_factor']
trans_energy_factor = params['trans_energy_factor']
# 基于时间约束求解rho飞行时间 = 计算时间 + 传输时间
# flight_time_factor * d = comp_time_factor * rho * d + trans_time_factor * (1-rho) * d
rho_time = (flight_time_factor - trans_time_factor) / (comp_time_factor - trans_time_factor)
# 基于能量约束求解最大照片数d
# battery_energy_capacity = flight_energy_factor * d + comp_energy_factor * rho * d + trans_energy_factor * (1-rho) * d
energy_per_photo = (flight_energy_factor +
comp_energy_factor * rho_time +
trans_energy_factor * (1 - rho_time))
max_photos = math.floor(battery_energy_capacity / energy_per_photo)
return max_photos, rho_time
def solve_greedy(params):
"""使用贪心算法求解任务分配问题"""
H = params['H']
W = params['W']
k = params['num_cars'] # 系统数量
car_time_factor = params['car_time_factor']
bs_time_factor = params['bs_time_factor']
flight_time_factor = params['flight_time_factor']
# 计算每次飞行能拍摄的最大照片数
photos_per_flight, rho = calculate_max_photos_per_flight(params)
print(f"贪心无人机计算的情况下,每次飞行能拍摄的最大照片数: {photos_per_flight}")
print(f"卸载率 rho: {rho:.3f}")
# 用较小的边长来划分网格
min_side = min(H, W)
next_side = photos_per_flight // min_side
# 初始化任务分配列表
tasks = [[] for _ in range(k)]
if min_side == H:
grid_h = min_side
grid_w = next_side
num_rows = 1
num_cols = round(W / grid_w)
current_col = 0
for i in range(math.ceil(num_cols / k)):
for j in range(k):
tasks[j].append((0, current_col))
current_col += 1
if current_col == num_cols:
break
else:
grid_w = min_side
grid_h = next_side
num_cols = 1
num_rows = round(H / grid_h)
current_row = 0
for i in range(math.ceil(num_rows / k)):
for j in range(k):
tasks[j].append((current_row, 0))
current_row += 1
if current_row == num_rows:
break
print(f"网格大小: {grid_w}x{grid_h}")
print(f"网格数量: {num_rows}x{num_cols}")
print(f"任务分配情况: {tasks}")
# 计算区域中心点
center_x = W / 2
center_y = H / 2
# 为每个系统计算完成时间
system_times = []
for i in range(k):
if not tasks[i]: # 如果该系统没有分配任务
system_times.append(0)
continue
# 生成该系统负责的网格中心坐标
grids = []
for row, col in tasks[i]:
if min_side == H:
# 如果H是较小边那么row=0col递增
# TODO 最后一个网格的中心点不能这么算
grid_center_x = (col + 0.5) * grid_w
grid_center_y = (row + 0.5) * grid_h
else:
# 如果W是较小边那么col=0row递增
grid_center_x = (col + 0.5) * grid_w
grid_center_y = (row + 0.5) * grid_h
grids.append((grid_center_x, grid_center_y))
# 计算车辆路径长度(从中心点出发)
car_distance = math.hypot(center_x - grids[0][0], center_y - grids[0][1]) # 从中心到第一个网格
for j in range(len(grids)-1):
car_distance += math.hypot(grids[j+1][0] - grids[j][0],
grids[j+1][1] - grids[j][1]) # 网格间距离
car_distance += math.hypot(grids[-1][0] - center_x,
grids[-1][1] - center_y) # 从最后一个网格回到中心
# 计算时间
num_photos = len(grids) * photos_per_flight # 该系统需要拍摄的总照片数
flight_time = flight_time_factor * num_photos # 飞行时间
car_time = car_time_factor * car_distance # 车辆移动时间
bs_time = bs_time_factor * (1 - rho) * num_photos # 基站计算时间
total_time = max(flight_time + car_time, bs_time)
system_times.append(total_time)
print(f"\n系统 {i} 详细信息:")
print(f"负责的网格数: {len(grids)}")
print(f"总照片数: {num_photos}")
print(f"车辆移动距离: {car_distance:.2f}")
print(f"飞行时间: {flight_time:.2f}")
print(f"车辆时间: {car_time:.2f}")
print(f"基站时间: {bs_time:.2f}")
print(f"总完成时间: {total_time:.2f}")
# 找出最大完成时间
max_time = max(system_times)
print(f"\n最大完成时间: {max_time:.2f}")
# 准备返回结果
result = {
'max_time': max_time,
'system_times': system_times,
'photos_per_flight': photos_per_flight,
'grid_w': grid_w,
'grid_h': grid_h,
'num_rows': num_rows,
'num_cols': num_cols,
'tasks': tasks,
'rho': rho
}
return result
def plot_results(params, result):
"""可视化结果"""
H = params['H']
W = params['W']
k = params['num_cars']
plt.rcParams['font.family'] = ['sans-serif']
plt.rcParams['font.sans-serif'] = ['SimHei']
# 创建图形
fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(15, 5))
# 1. 绘制系统完成时间对比
ax1.bar(range(k), result['system_times'])
ax1.set_title('各系统完成时间对比')
ax1.set_xlabel('系统编号')
ax1.set_ylabel('完成时间(秒)')
# 2. 绘制网格划分示意图
ax2.set_xlim(0, W)
ax2.set_ylim(0, H)
# 为不同系统的网格使用不同颜色
colors = plt.cm.rainbow(np.linspace(0, 1, k))
# 绘制网格和系统分配
grid_w = result['grid_w']
grid_h = result['grid_h']
tasks = result['tasks']
# 绘制每个系统的网格
for system_idx, system_tasks in enumerate(tasks):
for row, col in system_tasks:
rect = patches.Rectangle(
(col * grid_w, row * grid_h),
grid_w, grid_h,
linewidth=1,
edgecolor='black',
facecolor=colors[system_idx],
alpha=0.3
)
ax2.add_patch(rect)
# 在网格中心添加系统编号
center_x = (col + 0.5) * grid_w
center_y = (row + 0.5) * grid_h
ax2.text(center_x, center_y, str(system_idx),
ha='center', va='center')
# 添加中心点标记
ax2.plot(W/2, H/2, 'r*', markersize=15, label='区域中心')
ax2.legend()
ax2.set_title('网格划分和系统分配示意图')
ax2.set_xlabel('宽度')
ax2.set_ylabel('高度')
plt.tight_layout()
plt.show()
def main():
# 读取参数
with open('params.yml', 'r', encoding='utf-8') as file:
params = yaml.safe_load(file)
# 求解
result = solve_greedy(params)
# 输出结果
print("\n求解结果:")
print(f"最大完成时间: {result['max_time']:.2f}")
print("\n各系统完成时间:")
for i, time in enumerate(result['system_times']):
print(f"系统 {i}: {time:.2f}")
# 可视化
plot_results(params, result)
if __name__ == "__main__":
main()