MATLAB: How to plot intermediate variables of a function used by ode45 solver

ode45 intermediate varaibles plot

Sir, I am calling ode45 for integrating a diff equation say x'=(1/(H))*(2x)
Main Program:
x0=0.1; final_time=1; [t,x]=ode45(@myfunc,[0,final_time],x0);% ODE Call plot(t(:,1),x(:,1))% plotting the state variable main ends
Function Program:
function dv=myfunc(t,x) H=1.0; Te=2*x(1);% intermediate calculations/variables for my differential equations %The Differential Equation dv=[(1/(H))*(Te)];
But i want to plot the intermediate variables say Te in this case.But ode returns t,x alone.How to plot the intermediate variables that was used in the integration process.

Best Answer

You can prepare your function such, that it replies the wanted value according to a special trigger method and accepts vectors as input also:
function dv = myfunc(t, x, flag)
H  = 1.0;
Te = 2 * x(:, 1)
dv = Te ./ H;      % Btw, No addition square brackets
if nargin == 3
  dv = Te;
end
Now run the integration at first:
[t,x] = ode45(@myfunc,[0,final_time],x0);
and obtain the internal variable afterwards:
Te = myFunc(t, x, 'flag');
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