python使用Dijkstra算法在给定的三维曲面上确定到n个曲面上的点的最佳选址,并绘制三维图像的例子
时间: 2024-02-19 09:58:02 浏览: 138
Python实现Dijkstra算法
以下是一个使用Python实现Dijkstra算法在三维曲面上确定到n个点的最佳选址,并绘制三维图像的例子:
```python
import numpy as np
import heapq
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
def dijkstra(start, end, vertices, edges):
"""
使用Dijkstra算法确定从起点到终点的最短路径
:param start: 起点
:param end: 终点
:param vertices: 所有点的坐标
:param edges: 所有边的权重
:return: 最短路径和对应的点坐标
"""
heap = [(0, start)]
visited = {start: 0}
path = {}
nodes = set(vertices)
while nodes and heap:
(weight, current) = heapq.heappop(heap)
if current == end:
return visited[end], get_path(end, path)
nodes.discard(current)
for neighbor in nodes:
cost = weight + edges.get((current, neighbor), np.inf)
if cost < visited.get(neighbor, np.inf):
visited[neighbor] = cost
heapq.heappush(heap, (cost, neighbor))
path[neighbor] = current
return np.inf, []
def get_path(end, path):
"""
获取最短路径
:param end: 终点
:param path: 路径字典
:return: 最短路径
"""
path_lst = [end]
while end in path:
end = path[end]
path_lst.append(end)
return path_lst[::-1]
def plot_surface(vertices, faces, values=None):
"""
绘制三维曲面
:param vertices: 所有点的坐标
:param faces: 所有面的索引
:param values: 每个点的值,用于颜色映射
"""
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
if values is not None:
cmap = plt.cm.get_cmap('cool')
normalize = plt.Normalize(vmin=min(values), vmax=max(values))
colors = [cmap(normalize(value)) for value in values]
ax.scatter(vertices[:, 0], vertices[:, 1], vertices[:, 2], c=colors)
else:
ax.scatter(vertices[:, 0], vertices[:, 1], vertices[:, 2])
for face in faces:
x = vertices[face, 0]
y = vertices[face, 1]
z = vertices[face, 2]
ax.plot_trisurf(x, y, z, linewidth=0.2, antialiased=True)
plt.show()
if __name__ == '__main__':
# 读取曲面数据
vertices = np.loadtxt('vertices.txt')
faces = np.loadtxt('faces.txt', dtype=int)
# 构建边和权重
edges = {}
for i in range(len(vertices)):
for j in range(i + 1, len(vertices)):
if (i, j) not in edges and (j, i) not in edges:
dist = np.linalg.norm(vertices[i] - vertices[j])
edges[(i, j)] = dist
edges[(j, i)] = dist
# 确定选址
n = 5 # 选址数量
start = np.random.randint(len(vertices))
selected = [start]
while len(selected) < n:
dists = []
for i in range(len(vertices)):
if i not in selected:
total_dist, _ = dijkstra(start, i, vertices, edges)
dists.append((total_dist, i))
dists.sort()
selected.append(dists[-1][1])
start = dists[-1][1]
# 绘制选址和曲面
values = np.zeros(len(vertices))
for i in selected:
values[i] = 1
plot_surface(vertices, faces, values)
```
该例子中,我们从文件中读取了三维曲面的顶点坐标和面的索引,然后使用Dijkstra算法确定了选址的位置,并用不同的颜色表示选址和曲面不同点的值。最后,我们使用matplotlib库绘制了三维图像。
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