Matlab coding ordinary differential equation initial condition graph not running in the initial condition

Matlab coding ordinary differential equation initial condition graph not running in the initial condition. For x(2), x(6) and x(7) only getting properly graph is coming with the initial condition starting but for x(1), x(3), x(4), x(5) graph is not coming as the initial condition starting
Tr()
30 successful steps 2 failed attempts 193 function evaluations Elapsed time is 0.072265 seconds.
function Tr
options = odeset('RelTol',1e-6,'Stats','on');
%initial conditions
Xo = [0.005; 0.0007; 0.001; 0.0001; 0.0001; 0; 0];
tspan = [0,120];
tic
[t,X] = ode45(@TestFunction,tspan,Xo,options);
toc
%figure
hold on
plot(t, X(:,1), 'green')
plot(t, X(:,2), 'blue')
plot(t, X(:,3), 'red')
plot(t, X(:,4), 'yellow')
plot(t, X(:,5), 'green')
plot(t, X(:,6), 'cyan')
plot(t, X(:,7), 'y')
%hold on
% legend('x1','x2')
% ylabel('x - Population')
% xlabel('t - Time')
%hold on
end
function [dx_dt]= TestFunction(~,x)
% Parameters
s = 0.038;
alpha = 0.02;
gamma = 0.10;
r = 0.03;
dH = 0.0083;
dX = 0.0125;
rho = 0.07;
K = 500;
beta = 0.0005;
theta = 0.03;
eta = 0.015;
muH = 0.015;
muI = 0.08;
lambdaP = 0.05;
lambdaL = 0.043;
UP = 0.20;
deltaP = 0.033;
UL = 0.50;
deltaL = 0.05;
kappa = 0.005;
dx_dt(1) = (s) - ((alpha * x(3) * x(1)) / (1 + gamma * x(1))) - (dH * x(1)) + (r * x(2));
dx_dt(2) = ((alpha * x(3) * x(1)) / (1 + gamma * x(1))) - ((r+dX) * x(2));
dx_dt(3) = ((rho * x(3)) * (1 - (x(3) + x(4)) / K)) - (beta * x(3) * x(5)) - (lambdaP * x(6) * x(3)) - (lambdaL * x(7) * x(3)) - (muH * x(3));
dx_dt(4) = (beta * x(3) * x(5)) - (lambdaP * x(6) * x(4)) - (lambdaL * x(7) * x(4)) - (muI * x(4)) - (kappa * x(5) * x(4));
dx_dt(5) = (theta * x(4)) - (eta * x(5));
dx_dt(6) = (UP) - (deltaP * x(6));
dx_dt(7) = (UL) - (deltaL * x(7));
dx_dt = dx_dt';
end
%hold on

4 件のコメント

Torsten
Torsten 2025 年 9 月 29 日
編集済み: Torsten 2025 年 9 月 29 日
If the results for x(1), x(3), x(4) and x(5) make no sense for you, you will have to check your parameters and equations for dx(1), dx(3), dx(4) and dx(5).
Sam Chak
Sam Chak 2025 年 9 月 29 日
編集済み: Torsten 2025 年 9 月 29 日
The responses for x1, x3, x4, and x5 begin from the specified initial values: {0.005, 0.001, 0.0001, 0.0001}.
options = odeset('RelTol', 1e-6);
X0 = [0.005; 0.0007; 0.001; 0.0001; 0.0001; 0; 0];
% x1 x2 x3 x4 x5 x6 x7
tspan = [0, 120];
[t, X] = ode45(@TestFunction, tspan, X0, options);
% figure(1)
% tL = tiledlayout(2, 2, 'TileSpacing', 'Compact');
%
% nexttile
% plot(t, X(:,1), 'color', '#AA0815'), grid on
% title('x1')
%
% nexttile
% plot(t, X(:,3), 'color', '#F0B41C'), grid on
% title('x3')
%
% nexttile
% plot(t, X(:,4), 'color', '#49B6A9'), grid on
% title('x4')
%
% nexttile
% plot(t, X(:,5), 'color', '#3D9BE1'), grid on
% title('x5')
%
% xlabel(tL, 'Time')
% ylabel(tL, 'Population')
figure(2)
tL2 = tiledlayout(2, 2, 'TileSpacing', 'Compact');
nexttile
plot(t, X(:,1), 'color', '#AA0815'), grid on
xlim([0, 120])
title('x1')
nexttile
plot(t, X(:,3), 'color', '#F0B41C'), grid on
xlim([0, 120])
title('x3')
nexttile
plot(t, X(:,4), 'color', '#49B6A9'), grid on
xlim([0, 120])
title('x4')
nexttile
plot(t, X(:,5), 'color', '#3D9BE1'), grid on
xlim([0, 120])
title('x5')
%title(tL2, 'Zoomed-in')
xlabel(tL2, 'Time')
ylabel(tL2, 'Population')
%% Dynamics of Population Growth
function [dx_dt]= TestFunction(~,x)
% Parameters
s = 0.038;
alpha = 0.02;
gamma = 0.10;
r = 0.03;
dH = 0.0083;
dX = 0.0125;
rho = 0.07;
K = 500;
beta = 0.0005;
theta = 0.03;
eta = 0.015;
muH = 0.015;
muI = 0.08;
lambdaP = 0.05;
lambdaL = 0.043;
UP = 0.20;
deltaP = 0.033;
UL = 0.50;
deltaL = 0.05;
kappa = 0.005;
dx_dt(1) = (s) - ((alpha * x(3) * x(1)) / (1 + gamma * x(1))) - (dH * x(1)) + (r * x(2));
dx_dt(2) = ((alpha * x(3) * x(1)) / (1 + gamma * x(1))) - ((r+dX) * x(2));
dx_dt(3) = ((rho * x(3)) * (1 - (x(3) + x(4)) / K)) - (beta * x(3) * x(5)) - (lambdaP * x(6) * x(3)) - (lambdaL * x(7) * x(3)) - (muH * x(3));
dx_dt(4) = (beta * x(3) * x(5)) - (lambdaP * x(6) * x(4)) - (lambdaL * x(7) * x(4)) - (muI * x(4)) - (kappa * x(5) * x(4));
dx_dt(5) = (theta * x(4)) - (eta * x(5));
dx_dt(6) = (UP) - (deltaP * x(6));
dx_dt(7) = (UL) - (deltaL * x(7));
dx_dt = dx_dt';
end
I want for 120 days x-axis 120 should come
Torsten
Torsten 2025 年 9 月 29 日
編集済み: Torsten 2025 年 9 月 29 日
Then adapt the "xlim" commands in the code (see above).

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