FFT for one 1*N Green function in MATLAB

[Zahra G]

I have a 1×N Green function in energy domain. I want to use the FFT (fast Fourier transform) for this Green function in MATLAB. But this function is non-periodic. Could you help me about this? How can I change the energy interval to convert Green function as a periodic function?

 

[f95toli]

I am not sure I understand what you are trying to do. Could you use zero-padding?

 

[Zahra G]

I defined zero matrix with zeros command in the binging of the program and calculate the Green function in energy domain then I converted the Green function to periodic function using for loop. Is it true=?