question about FDTD

hi everyone

I am studying FDTD now.But I have some problems about it.For instance,the explanations of YEE grids in books.It says through alternational iterations of electric field and magnetic field in time axis,we can get electromagnetic results.However, I do not understand how to get initial values of electromagnetic which is used in alternational iterations.Please give me some hints or assists,Thanks!!!!!

Hi!
The initial values of em field is set to zero excpet at the source region(where the values are determined by the excitation).
And then, the alternational iterations begin.

Thank you Fuga!!Do you have any codes(matlab) or
informations which is about source excitation?Please give me some.Thanks!!!

you can refer to link:

http://www.mathworks.com/matlabcentr...oadCategory.do
search: fdtd

that link is are code software matlab.

see Dennis Sulivan book it has many codes

Here u can find some simple FDTD code for matlab.
h**p://www.elmagn.chalmers.se/courses/CEM/examples/

Enjoy!

Thank you Fuga!
Now I have another problem.I have tested a 1D example in matlab.However,I found that Gaussian Pulse distorted when EM transmitting. Especially, Gaussian Pulse width is narrow,relatively.Which error causes this phenomena?numerical calculation, narrow width of Gaussian Pulse or some others?Thanks!!!

I don't know exactly your problem.
what kind of medium does the gaussian pulse propagate in?
what's ur boundary condition?