SI Epidemic Model传染病学模型（Matlab完整源码和数据）

% This script needs the file Fsi.m to run % Fsi.m contains the differential equation model % S is the number of Susceptible individuals at each time step % I is the number of Infected individuals at each time step N=1000; %Population Size %-- initial condictions i0=5; % initial condiction for I s0=N-i0; % initial condiction for S % -- T=100; % evaluation time %-- parameters beta=0.1; % infectious rate %-- S0I0=[s0 i0]; % initial condictions Vector Tspam=[0:0.1:T]; % time interval %-- Numerical Integration [T,Y] = ode45(@(t,Y) Fsi(t,Y,beta,N),Tspam,S0I0); %-- S=Y(:,1); % Solution S I=Y(:,2); % Solution I %----- plots ----- plot(T,S,'k'); hold on; grid on; plot(T,I,'r--'); title(['SI model with parameters: \beta= ',num2str(beta),' N=',num2str(N)]) xlabel('Time') ylabel('Number of Individuals') legend('S','I','Location','best') %------------------