Why am I getting error in event function for impulsive differential equations?
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function sol = paper_impulse
t0 = 0; t1 = 5;
impcount = 0; te=1; k=1; No = 1; ep=0.01; vec = []; x = []; i=0; impulse_strength = 1.2;
v=zeros(201);
while(i<5)
i = i+0.01;
x = [x, i];
end
disp(x)
x= round(x*100)/100;
while true
if (impcount ==0)
options = odeset('Events',@events,'AbsTol',1e-5,'RelTol',1e-5);
sol = ode45(@neural_network, [t0, t1], [3 5], options);
else
% Specify the new solution at impulse times...
options = odeset(options,'InitialY',[impulse_strength*sol.y(1,end) impulse_strength*sol.y(2,end)]);
sol = ode45(@neural_network, [t0, t1], sol, options);
end
t0 = sol.x(end);
fprintf('Restart at %5.2f.\n',t0);
vec = [vec,te];
ind = find(abs(x-te)<0.001);
v(ind) = v(ind) + impulse_strength;
fprintf('Restart at %5.2f.\n',ind);
k=k+1;
if(mod(k,No) == 0)
te = te+ No*(0.02-ep)+ep;
else
te = te+ ep;
end
impcount = impcount + 1;
if (t0 >= t1)
break;
end
end
plot(sol.x, sol.y(1,:));
hold on
plot(sol.x, sol.y(2,:));
%disp(size(vec));
%stem(vec, v);
%axis([1 5 0 impulse_strength*2]);
%xlabel('time');
%ylabel('impulse strength');
function dy = neural_network(t,y)
dy = zeros(2,1);
dy(1) = -1/2*y(1)-y(1).^3+y(1).*y(2).^2-((y(1).^2+y(2).^2).^1/4).*sign(y(1));
dy(2) = -1/2*y(2)-y(2).^3-y(2).*y(1).^2-((y(1).^2+y(2).^2).^1/4).*sign(y(2));
end
function [value,isterminal,direction] = events(t,y)
value = t-te;
isterminal = 1;
direction = 0;
end
end
The above code is for impulsive differential equation. I have used the event function to locate the moments at which the solution has jump kind of discontinuites. But code is compiling with errors. Please help to short out this problem.
2 comentarios
Torsten
el 13 de Jun. de 2022
From the code I see, "te" seems to be undefined when you first call ode45.
Respuestas (1)
Walter Roberson
el 13 de Jun. de 2022
https://www.mathworks.com/help/matlab/ref/ddeset.html
InitialY is only for Delay Differential Equations using ddeset()
2 comentarios
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