Matlab ode45 solving differential equations

1、 Content abstract

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418- Can communicate 、 consulting 、 Answering question

2、 Content description

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3、 Simulation analysis

function dy = odefun(t,y)
lameda = 0.2;
alpha = 0.35;
beta = 15;
miu = 0.3;
theta = 0.05;
phi = 0.4;
dy = zeros(4,1);    % 
S = y(1);
E = y(2);
I = y(3);
R = y(4);
dy(1) = -lameda*beta*I*S-theta*beta*I*S;
dy(2) = lameda*beta*I*S-(alpha+phi)*E;
dy(3) = alpha*E-miu*I;
dy(4) = theta*beta*I*S+phi*E+miu*I;
end

%-----------------------------------------------------
%  Clear all variables 
clear
%  Clear the screen 
clc
close all
%  Time span 0-120, Can be separated by spaces , You can also use commas to separate 
tspan = [0,40];
%  Initial value 
S_0 = 0.9998;E_0 = 0; I_0 = 0.0002; R_0 = 0;
y0 = [S_0 E_0 I_0 R_0];
%  Call statement 
[T1,Y1] = ode45( @odefun, tspan, y0);
%  mapping 
figure
plot(T1,Y1(:,1))
xlabel  Time 
ylabel S
title '\Lambda=0.2'
figure
plot(T1,Y1(:,2))
xlabel  Time 
ylabel E
title '\Lambda=0.2'
figure
plot(T1,Y1(:,3))
xlabel  Time 
ylabel I
title '\Lambda=0.2'
figure
plot(T1,Y1(:,4))
xlabel  Time 
ylabel R
title '\Lambda=0.2'

4、 Reference paper

 

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