ODE code is not working

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Mr.DDWW
Mr.DDWW 2022-4-28
回答： Star Strider 2022-4-28
I tried to run the code but it is not working. here is the code
here is the code
clc;clf;clear all;close all;
syms X(t) Y(t) Z(t) YF alpha beta gamma1 gamma2 T theta
% The given data
YF=0.0667;
alpha= 0.29;
beta= 0.68;
gamma1=450;
gamma2=11.25;
theta=0.10895;
Ode1 = diff(X) == -X/theta + (1+alpha)*gamma1*(1-X)*Y^2 + beta*gamma1*(1-X)*Z^2;
Ode2 = diff(Y) == (YF-Y)/theta+(1-alpha)*gamma1*(1-X)*Y^2-gamma2*Y;
Ode3 = diff(Z) == -Z/theta+beta*gamma1*(1-X)*Z^2+2*alpha*gamma1*(1-X)*Y^2-(gamma2*Z)/beta;
Odes = [Ode1;Ode2; Ode3];
[VF, Subs] = OdeToVectorField ([Ode1, Ode2,Ode3]);
M = matlabFunction (VF, 'Vars',{'T','Y'});
% The given condtions
[t,y]=ode45(M, [0 5],[0.0667 0 0]);
figure
plot(t,y(:,1:2))
gride on
title('X and Y')
legend (string(subs))
[t,y]=ode45(M, [100 120],[0.0667 0 0]);
figure
plot(t,y(:,1:2))
gride on
title('X and Y')
legend (string(subs))
[t,y]=ode45(M, [100 120],[0.0667 0 0]);
figure
plot(t,y(:,1),t,y(:,2))
gride on
title('X vs Y')
legend (string(subs))

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回答（1 个）

Star Strider
Star Strider 2022-4-28
Ran in:
Problem:
[VF, Subs] = OdeToVectorField ([Ode1, Ode2,Ode3]);
↑
Try this —
syms X(t) Y(t) Z(t) YF alpha beta gamma1 gamma2 T theta
% The given data
YF=0.0667;
alpha= 0.29;
beta= 0.68;
gamma1=450;
gamma2=11.25;
theta=0.10895;
Ode1 = diff(X) == -X/theta + (1+alpha)*gamma1*(1-X)*Y^2 + beta*gamma1*(1-X)*Z^2;
Ode2 = diff(Y) == (YF-Y)/theta+(1-alpha)*gamma1*(1-X)*Y^2-gamma2*Y;
Ode3 = diff(Z) == -Z/theta+beta*gamma1*(1-X)*Z^2+2*alpha*gamma1*(1-X)*Y^2-(gamma2*Z)/beta;
Odes = [Ode1;Ode2; Ode3];
[VF, Subs] = odeToVectorField ([Ode1, Ode2,Ode3]); % <— Corrected Misspelling
M = matlabFunction (VF, 'Vars',{'T','Y'});
% The given condtions
[t,y]=ode45(M, [0 5],[0.0667 0 0]);
figure
plot(t,y(:,1:2))
grid on
title('X and Y')
legend (string(Subs))
Warning: Ignoring extra legend entries.
[t,y]=ode45(M, [100 120],[0.0667 0 0]);
figure
plot(t,y(:,1:2))
grid on
title('X and Y')
legend (string(Subs))
Warning: Ignoring extra legend entries.
[t,y]=ode45(M, [100 120],[0.0667 0 0]);
figure
plot(t,y(:,1),t,y(:,2))
grid on
title('X vs Y')
legend (string(Subs))
Warning: Ignoring extra legend entries.
MATLAB is case-sensitive.
.

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