# how to interpolate the data over uniform time grid

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PetronasAMG on 26 Sep 2021
Commented: Mathieu NOE on 27 Sep 2021
Since numerical solution obtained from ode45 is a non uniform in time, I need to obtain the frequency power spectrim of the solution, but first, i need to interpolate the date over unifrom time grid. How would i able to do so? I am completely stuck after inputting vlause from ODE45! Please explain the steps!
function dxdt = frs(t,x)
dxdt = zeros(3,1);
dx1dt = -((4/5)*x(2)+x(1));
dx2dt = x(3) + ((4/9)*x(2));
dx3dt = (1/8)+((x(1)-2.5)*x(2));
end
tspan = [0:10:100];
xi = [1.0;4.0;2.0];
[t,x]= ode45(@frs,tspan,xi);
##### 2 CommentsShowHide 1 older comment
Mathieu NOE on 27 Sep 2021
you can also interpolate the output data of your ode solution over a new time vector (linear)
use interp1
maybe this will be faster than forcing ode to work on fixed , refined time vector

R2021b

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