Solution of ODE in different time intervals

I want to solve ODE as a function over three different intervals [0,1],[1,1.2] and [1.2,3].

My function to solve my ODE is "solveODE" as following:

    function [x, tinter, xinter] = solveODE(xdot, T, t0, ...
                                    x0, u)
            [tinter,xinter] = ode45(xdot, ...
                [t0, t0+T], x0,u);
            x = xinter(size(xinter,1),:);

     end

where: "xdot" is my ODE function here k1 is constant has different valuesaccording to each of three intervals.

ODE function to be solved is as following:

function xprime = xdot(t, x, u, T)
    xprime =[x(2);...
        -k1*x(2)+k4*u(1)];
end

[Jan]

What is your question? Which problems do you observe? How do you call solveODE?

[maro]

y file is complicated but I will make it simpler. if I have this simple ODE function:

    function xdot=m(x,t)
     xdot=k1*x(1);
    end

Where k1 is a constant changing according to the time intervals (say for [0,1] k1=1, for [1,3] k1=2, for [3,10] k1=3).

I want to solve that ODE with ode45 command as a function over the different three intervals for example:

      function [x, tinter, xinter]=solveODE(xdot,T,t0,x0)
      [tinter,xinter] = ode45(system,[t0, t0+T], x0, options, u);
              x = xinter(size(xinter,1),:);
      end

where t0 change every iteration.