How can I plot ode 45 for different values of a constant after specific time?

I want to change the value of del after given time interval.

T = 1:1:3500;
del = 0;        % For T=1:1:3100
del = 1;        % For T=3100:1:3500
[t,y] = ode45(@f_1,T,C);

This is the only line of the function which contains del.

dy(4,1)=(y(1)*k(1))/V(4) - (y(4)*(k(1) + k(2) + k(3) + del*k_clear))/V(4) + (y(2)*k(2))/V(4) + (y(3)*k(3))/V(4);

I want to plot this graph

But was able to construct this.

[madhan ravi]

Share your ode function.Why not?

function dydt = myod(t,y)
.....

if  t <= 3100
    del = 0;
else
    del = 1;   
end
.... rest of the code
end

Answer 1

[Torsten]

function main
  T = 1:1:3100;
  del = 0.0;
  [t1,y1] = ode45(@(t,y)f_1(t,y,del),T,C);
  T = 3100:1:3500;
  del = 1.0;
  C = y1(end,:);
  [t2,y2] = ode45(@(t,y)f_1(t,y,del),T,C);
  t = [t1;t2];
  y = [y1;y2];
  plot(t,y)
end

function dy = f_1(t,y,del)
  ...
end

[Usman Saleem]

Thanx bro, got same result.