前言
利用有限元方法计算一些数值问题，经常需要剖网格，得到的网格拓扑信息，如果能图形化显示对我们Debug程序也方便，下面利用Python语言读取文本中的网格拓扑信息，然后图形化显示，且可以选择是否显示节点或者单元编号信息。具体代码和数据可以去我的 Github下载。
数据格式
1. 节点数据格式
id_1 x1 y1
id_2 x2 y2
…
For Example (Node.txt)
1 0 0
2 5 0
3 5 4
4 0 4
5 0 2
6 1 1
7 2 1
8 2 2
9 1 2
10 1 1.5
2. 单元编号数据格式
id_1 tri_id1 tri_id2 tri_id3 tag
id_2 tri_id1 tri_id2 tri_id3 tag
…
注：tag 有时可以表示这个三角形单元的一些特殊信息，画图时亦可以用其显示三角形颜色。
For Example (Triangles.txt)
1 41 42 46 3.7
2 29 7 43 3.7
3 34 14 38 3.7
4 42 35 46 3.7
5 11 44 59 3.7
6 35 42 49 3.7
7 34 38 43 3.7
8 38 29 43 3.7
9 41 24 42 3.7
10 41 46 61 3.7
程序
1 读取节点信息
def read_Nodes(node_file):
Nodes = []
f = open(node_file)
lines = f.readlines()
for line in lines:
data = re.findall(r'\d+\.?\d*', line)
id = int(data[0])
x = float(data[1])
y = float(data[2])
da = [x, y]
Nodes.append(da)
return Nodes
2 读取网格拓扑信息
def read_Triangles(triangle_file):
Triangles = []
Tags = []
f = open(triangle_file)
lines = f.readlines()
for line in lines:
data = re.findall(r'\d+\.?\d*', line)
id = int(data[0])
id_1 = int(data[1])
id_2 = int(data[2])
id_3 = int(data[3])
tag = float(data[4])
da = [id_1, id_2, id_3]
Triangles.append(da)
Tags.append(tag)
return Triangles, Tags
3 网格图形化
def plotMesh(Nodes, Triangles, Tags, showNodeId = True, showTriangleId = True, showTriangleTag = False):
fig, ax = plt.subplots()
patches = []
triangleId = 0
colors = []
for triangle in Triangles:
triangleId = triangleId + 1
polygon = []
colors.append(Tags[triangleId-1])
for id in triangle:
polygon.append(Nodes[id-1])
for i in range(len(polygon)):
line_x = []
line_y = []
line_x.append(polygon[i][0])
if i+1 == len(polygon) :
line_x.append(polygon[0][0])
else:
line_x.append(polygon[i+1][0])
line_y.append(polygon[i][1])
if i+1 == len(polygon) :
line_y.append(polygon[0][1])
else:
line_y.append(polygon[i+1][1])
plt.plot(line_x, line_y, 'r-')
patches.append(Polygon(polygon, True))
center_x = sum([_[0] for _ in polygon]) / len(polygon)
center_y = sum([_[1] for _ in polygon]) / len(polygon)
if showTriangleId :
ax.annotate(triangleId, (center_x, center_y), color='red', weight='bold', fontsize=7, ha='center', va='center')
if showNodeId :
nodeId = 0
for node in Nodes:
nodeId = nodeId + 1
ax.annotate(nodeId, (node[0], node[1]), color='black', weight='bold', fontsize=9, ha='center', va='center')
collection = PatchCollection(patches)
if showTriangleTag :
collection.set_array(np.array(colors))
ax.add_collection(collection)
fig.colorbar(collection, ax=ax)
ax.axis('equal')
plt.show()
4 完整代码
import re
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon
from matplotlib.collections import PatchCollection
def read_Nodes(node_file):
Nodes = []
f = open(node_file)
lines = f.readlines()
for line in lines:
data = re.findall(r'\d+\.?\d*', line)
id = int(data[0])
x = float(data[1])
y = float(data[2])
da = [x, y]
Nodes.append(da)
return Nodes
def read_Triangles(triangle_file):
Triangles = []
Tags = []
f = open(triangle_file)
lines = f.readlines()
for line in lines:
data = re.findall(r'\d+\.?\d*', line)
id = int(data[0])
id_1 = int(data[1])
id_2 = int(data[2])
id_3 = int(data[3])
tag = float(data[4])
da = [id_1, id_2, id_3]
Triangles.append(da)
Tags.append(tag)
return Triangles, Tags
def plotMesh(Nodes, Triangles, Tags, showNodeId = True, showTriangleId = True, showTriangleTag = False):
fig, ax = plt.subplots()
patches = []
triangleId = 0
colors = []
for triangle in Triangles:
triangleId = triangleId + 1
polygon = []
colors.append(Tags[triangleId-1])
for id in triangle:
polygon.append(Nodes[id-1])
for i in range(len(polygon)):
line_x = []
line_y = []
line_x.append(polygon[i][0])
if i+1 == len(polygon) :
line_x.append(polygon[0][0])
else:
line_x.append(polygon[i+1][0])
line_y.append(polygon[i][1])
if i+1 == len(polygon) :
line_y.append(polygon[0][1])
else:
line_y.append(polygon[i+1][1])
plt.plot(line_x, line_y, 'r-')
patches.append(Polygon(polygon, True))
center_x = sum([_[0] for _ in polygon]) / len(polygon)
center_y = sum([_[1] for _ in polygon]) / len(polygon)
if showTriangleId :
ax.annotate(triangleId, (center_x, center_y), color='red', weight='bold', fontsize=7, ha='center', va='center')
if showNodeId :
nodeId = 0
for node in Nodes:
nodeId = nodeId + 1
ax.annotate(nodeId, (node[0], node[1]), color='black', weight='bold', fontsize=9, ha='center', va='center')
collection = PatchCollection(patches)
if showTriangleTag :
collection.set_array(np.array(colors))
ax.add_collection(collection)
fig.colorbar(collection, ax=ax)
ax.axis('equal')
plt.show()
if __name__ == "__main__":
node_file = "Nodes.txt"
triangle_file = "Triangles.txt"
Nodes = read_Nodes(node_file)
Triangles, Tags = read_Triangles(triangle_file)
showNodeId = True
showTriangleId = True
plotMesh(Nodes, Triangles, Tags, showNodeId, showTriangleId)
结果
1. 不显示编号信息
2. 显示编号信息
