ODE45 change y at event

Can i influence the 'y' during an ode45 at a certain event?

I want to let the ODE45 stop at a certain event, manipulate the result at that timepoint and let it run further using the manipulated result as initial condition.A basic example is this:

spawnday=250;

function [value,isterminal,direction] = half_y_at_event(t, y, spawnday)
  value = [t-spawnday];  
  isterminal = [1]; 
  direction  = [];   
end

options=odeset('Events', @half_y_at_event, 'AbsTol', 1e-8, 'RelTol', 1e-8);

[t1, y1, te, ye, ie] = ode45(@dget_y, [0 500], [y_0], options, [pars]);
ye=ye/2;
[t2, y2] = ode45(@dget_y, [0 500], [ye], options, [pars]);

Is there a possibility to combine both ODE45 into one?

Mergin the matrices later is not an option.

[darova]

Using ode45 two times?

[t1, y1, te, ye, ie] = ode45(@dget_y, [0 500], [y_0], options, [pars]);
ye = ye/2;
[t2, y2] = ode45(@dget_y, [0 500]+t1(end), ye(:,end));

[bstechel]

Using 2 ODE45 Is not convenient here since the event will occur multiple times over the total timespan of the ODE45 i'm interested in.

Answer 1

[Steven Lord]

You can use the ballode example as a model. That has an events function that stops the solver each time the bouncing ball touches the ground. It then changes the initial condition (based on the solution the solver gave when the event occurred) and starts the solver again with the new initial condition.

edit ballode

[bstechel]

Ballode also loops the ode multiple times and merges the matrices. I guess there's no way around it.

[Corentin Dewez-Raszka]

Hey, sorry to disturb, but I have the ame problem you did, where can I get the code for ballode ?

EDIT : nevermind, found it, thx guys

[bstechel]

type: edit ballode