nx.draw_vertex

nx.draw_vertex是一个函数，它是NetworkX库中用于绘图形的一个方法。它可以用来绘制图中的节点（顶点）。

使用nx.draw_vertex函数可以将图中的节点以指定的方式绘制出来，例如可以使用不同的颜色、形状或大小来表示不同的节点属性。这个函数可以接受多个参数，其中最重要的参数是图对象和节点位置信息。

具体来说，使用nx.draw_vertex函数需要以下步骤：
1. 创建一个图对象，可以使用NetworkX提供的各种图形生成函数来创建。
2. 使用其他NetworkX函数或方法对图进行操作，例如添加节点、添加边等。
3. 使用nx.draw_vertex函数来绘制图中的节点，可以设置节点的颜色、形状、大小等属性。
4. 可以使用其他绘图函数或方法来添加边、标签等其他元素。

注意，nx.draw_vertex函数只能绘制节点，如果需要绘制边或其他元素，需要使用其他相关的函数或方法。

相关问题

修改class arcnode: def __init__(self, adjvex, weight, link=None): self.adjvex = adjvex self.weight = weight self.link = link class vexnode: def __init__(self, data, first_arc=None): self.data = data self.first_arc = first_arc class Graph: def __init__(self): self.vex_list = [] self.vex_num = 0 self.edge_num = 0 # 请在这里填写答案 def addVertex(self, vex_val): new_vertex = vexnode(vex_val) self.vex_list.append(new_vertex) self.vex_num += 1 def addEdge(self, f, t, cost=0): if f not in self.vex_list: nv = self.addVertex(f) # 如果起始顶点不存在，则将其添加到图中 if t not in self.vex_list: nv = self.addVertex(t) # 如果目标顶点不存在，则将其添加到图中 # 无向图添加双向边 self.vex_list[f].addNeighbor(self.vex_list[t], cost) # 将目标顶点及其权重添加到起始顶点的 connectedTo 字典中 self.vex_list[t].addNeighbor(self.vex_list[f], cost) # 有向图只添加一条边 # 请在这里填写答案 def print_graph(self): for i in range(self.vex_num): print(self.vex_list[i].data, end="->") cur = self.vex_list[i].first_arc while cur: print("adj:{},weight:{}".format(cur.adjvex, cur.weight), end="->") cur = cur.link print('None') if __name__ == "__main__": g = Graph() s = input() for vertex in s: g.addVertex(vertex) g.addEdge(0, 1, 11) g.addEdge(0, 2, 55) g.addEdge(2, 3, 88) g.addEdge(0, 3, 33) g.addEdge(1, 2, 44) g.print_graph()

class arcnode:
def __init__(self, adjvex, weight, link=None):
self.adjvex = adjvex
self.weight = weight
self.link = link

class vexnode:
def __init__(self, data, first_arc=None):
self.data = data
self.first_arc = first_arc

class Graph:
def __init__(self):
self.vex_list = []
self.vex_num = 0
self.edge_num = 0

def addVertex(self, vex_val):
new_vertex = vexnode(vex_val)
self.vex_list.append(new_vertex)
self.vex_num += 1

def addEdge(self, f, t, cost=0):
if f not in range(self.vex_num):
raise ValueError("Invalid Starting Vertex")
if t not in range(self.vex_num):
raise ValueError("Invalid Ending Vertex")
new_arc = arcnode(t, cost)
new_arc.link = self.vex_list[f].first_arc
self.vex_list[f].first_arc = new_arc
self.edge_num += 1

def print_graph(self):
for i in range(self.vex_num):
print(self.vex_list[i].data, end="->")
cur = self.vex_list[i].first_arc
while cur:
print("adj:{},weight:{}".format(cur.adjvex, cur.weight), end="->")
cur = cur.link
print('None')

if __name__ == "__main__":
g = Graph()
s = input()
for vertex in s:
g.addVertex(vertex)
g.addEdge(0, 1, 11)
g.addEdge(0, 2, 55)
g.addEdge(2, 3, 88)
g.addEdge(0, 3, 33)
g.addEdge(1, 2, 44)
g.print_graph()

将下列代码改为vs内可运行的代码：float smoothCot() { float err = -1; cogs.clear(); v_end = mesh.vertices_end(); // for (v_it = mesh.vertices_begin(); v_it != v_end; ++v_it) { cog[0] = cog[1] = cog[2] = valence = 0.0; for (vv_it = mesh.vv_iter(*v_it); vv_it.is_valid(); ++vv_it) { double cot_weight = 0.0; MyMesh::HalfedgeHandle heh = mesh.find_halfedge(*v_it, *vv_it); if (!mesh.is_boundary(heh)) { MyMesh::HalfedgeHandle prev_heh = mesh.prev_halfedge_handle(heh); MyMesh::HalfedgeHandle next_heh = mesh.next_halfedge_handle(heh); MyMesh::VertexHandle prev_vh = mesh.to_vertex_handle(prev_heh); MyMesh::VertexHandle next_vh = mesh.to_vertex_handle(next_heh); MyMesh::Point prev_p = mesh.point(prev_vh); MyMesh::Point curr_p = mesh.point(*v_it); MyMesh::Point next_p = mesh.point(next_vh); double cot_alpha = cot(prev_p - curr_p, next_p - curr_p); double cot_beta = cot(curr_p - prev_p, next_p - prev_p); cot_weight = cot_alpha + cot_beta; } cog += cot_weight * mesh.point(*vv_it); valence += cot_weight; } cogs.push_back(cog / valence); } for (v_it = mesh.vertices_begin(), cog_it = cogs.begin(); v_it != v_end; ++v_it, ++cog_it) { if (!mesh.is_boundary(*v_it)) { MyMesh::Point p = mesh.point(*v_it); err = max(err, (p - *cog_it).norm()); mesh.set_point(*v_it, *cog_it); } } return err; }

请注意，代码中使用了 MyMesh 类型，需要先定义和引入该类型，以下是修改后的可运行代码：

#include <OpenMesh/Core/IO/MeshIO.hh>
#include <OpenMesh/Core/Mesh/TriMesh_ArrayKernelT.hh>
#include <vector>

typedef OpenMesh::TriMesh_ArrayKernelT<> MyMesh;

float smoothCot(MyMesh& mesh) {
    float err = -1;
    std::vector<MyMesh::Point> cogs;
    cogs.reserve(mesh.n_vertices());
    MyMesh::VertexIter v_it, v_end;
    MyMesh::VertexVertexIter vv_it;
    MyMesh::Point cog;
    double valence;
    v_end = mesh.vertices_end();
    for (v_it = mesh.vertices_begin(); v_it != v_end; ++v_it) {
        cog[0] = cog[1] = cog[2] = valence = 0.0;
        for (vv_it = mesh.vv_iter(*v_it); vv_it.is_valid(); ++vv_it) {
            double cot_weight = 0.0;
            MyMesh::HalfedgeHandle heh = mesh.find_halfedge(*v_it, *vv_it);
            if (!mesh.is_boundary(heh)) {
                MyMesh::HalfedgeHandle prev_heh = mesh.prev_halfedge_handle(heh);
                MyMesh::HalfedgeHandle next_heh = mesh.next_halfedge_handle(heh);
                MyMesh::VertexHandle prev_vh = mesh.to_vertex_handle(prev_heh);
                MyMesh::VertexHandle next_vh = mesh.to_vertex_handle(next_heh);
                MyMesh::Point prev_p = mesh.point(prev_vh);
                MyMesh::Point curr_p = mesh.point(*v_it);
                MyMesh::Point next_p = mesh.point(next_vh);
                double cot_alpha = cot(prev_p - curr_p, next_p - curr_p);
                double cot_beta = cot(curr_p - prev_p, next_p - prev_p);
                cot_weight = cot_alpha + cot_beta;
            }
            cog += cot_weight * mesh.point(*vv_it);
            valence += cot_weight;
        }
        cogs.push_back(cog / valence);
    }
    std::vector<MyMesh::Point>::iterator cog_it = cogs.begin();
    for (v_it = mesh.vertices_begin(); v_it != v_end; ++v_it, ++cog_it) {
        if (!mesh.is_boundary(*v_it)) {
            MyMesh::Point p = mesh.point(*v_it);
            err = std::max(err, (p - *cog_it).norm());
            mesh.set_point(*v_it, *cog_it);
        }
    }
    return err;
}

int main(int argc, char **argv) {
    MyMesh mesh;
    if (!OpenMesh::IO::read_mesh(mesh, argv[1])) {
        std::cerr << "read error\n";
        return 1;
    }
    std::cout << "smoothCot error: " << smoothCot(mesh) << std::endl;
    if (!OpenMesh::IO::write_mesh(mesh, "output.obj")) {
        std::cerr << "write error\n";
        return 1;
    }
    return 0;
}

其中，cot 函数需要自己实现，如下：

double cot(const MyMesh::Point& v1, const MyMesh::Point& v2) {
    return std::tan(MyMesh::Angle(v1, v2));
}

请注意，以上代码仅供参考，可能存在错误或不足之处，需要结合具体情况进行修改和完善。