【实例简介】用matlab编程实现无标度度网络算法

【实例截图】

【核心代码】

% This is the BA_Scale Model by Fan Jin.

% At first there are only m nodes and no edge, then the m 1st node is

% connected with the above m nodes

% usage: Nodes = BA(N,m)

% the parameter:N----network size

% m----a new node with m new edges

% can randomly initialize the N and the m by yourself

% the diagonal elements of the matrix also equal to -degree

% Nodes----the final coupling matrix

% The following message(s) may not be displayed correctly for they contain Chinese charactors.

% list----生成的一个辅助向量，该向量中的元素为每条边端点的节点。for example, 假设网络中节点4的度为7，则在list向量中会存在7个4，而这7个4的位置不一定是连续在一起的。

% preferential attachment体现在随机的从list向量中选取元素，选中哪个元素，该元素表示的节点即被选中。由于list向量中每个节点的个数与它的度有关，因此，度越大的点被选中的概率越大。

function [Nodes,Cii]=BA(N,m)

% N=10,m=3;

Nodes=zeros(N);

Cii=zeros(1,N);

t=zeros(1,N);

%Nodes=sparse(N);

for i=1:m

Nodes(i,m 1)=1;

Nodes(m 1,i)=1;

A(i)=i;

end

for i=m 1:2*m

A(i)=m 1;

end

for n=m 2:N % start from m 2 to grow the network

t=2*m*(n-m-1) ; % for list, every time t increases 2m

% t=m*(n-m-1);

for i=1:m

A(t i)=n; % in the list, every time the above m is n, it represents that the nth nodes is connected to other m nodes

end

k=1;

while k

p(k)=round((t 1)*rand(1)); % random choose an integer from 1~N

if p(k)>0&p(k)

if Nodes(n,A(p(k)))==0

A(t m k)=A(p(k));

Nodes(n,A(p(k)))=1;

Nodes(A(p(k)),n)=1;

k=k 1;

end %end for j

end %end for k

end %end for n

end

%Write_Sparse_Matrix(Nodes,['BA',num2str(N),'.txt']);

%Write_into_Pajek(Nodes,['BA',num2str(N),'.net']);

% for i=1:N

% Nodes(i,i)=sum(Nodes(:,i));

% Cii(i)=Nodes(i,i);

% end

for i=1:N

Cii(i)=sum(Nodes(:,i));

t(i)=A(i);

end