Discrepancy with easy ODE.
4 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Bobby Fischer
il 14 Gen 2021
Commentato: Bobby Fischer
il 14 Gen 2021
Hello, don't know why the discrepancy.
function fcno
y0=linspace(0,2,20);
t0=linspace(0,3,100);
figure(1)
close(1)
figure(1)
options=odeset('RelTol',1e-5);
subplot(1,3,1)
hold on
for k=1:20
[t,y]=ode45(@fun,t0,y0(k),options);
plot(t,y,'b')
end
title('ode')
subplot(1,3,2)
hold on
t=t0;
for k=1:20
f2=y0(k)*exp(t)./(1+(exp(t)-1)*y0(k));
plot(t,f2,'r')
end
title('solution')
%%
lon=101;
t=linspace(0,3,lon);
h=3/(lon-1);
y0=linspace(0,2,20);
subplot(1,3,3)
hold on
for m=1:20
y=zeros(1,lon);
y(1)=y0(m);
for k=1:100
y(k+1)=y(k)+h*y(k)*(1-y(k));
end
plot(t,y,'g')
end
plot([0 3],[0 0],'m--','linewidth',3)
plot([0 3],[1 1],'m--','linewidth',3)
title('my ode')
%%
function [t,yp]=fun(t,y)
yp=y*(1-y);
end
end
2 Commenti
Mischa Kim
il 14 Gen 2021
Hi Bobby, can you please provide more information of what you are trying to accomplish and the (unexpected) results you receive?
Risposta accettata
J. Alex Lee
il 14 Gen 2021
You have a syntax error on what your odefun is returning. To fix:
function [yp]=fun(t,y)
yp=y*(1-y);
end
Più risposte (0)
Vedere anche
Categorie
Scopri di più su Historical Contests in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!