ADI-FDTD in MATLAB

[ghasem]

Hi.
Is there anyone who is familiar with ADI-FDTD method and have matlab code for it?
I need help...

[ghasem]

please help me...

[Nasser M. Abbasi]

On 4/15/2013 3:11 AM, ghasem wrote:
> please help me...
>

If you go to

http://12000.org/my_notes/my_matlab_functions/index.htm

and search for the string "ADI " on the page

You'll find one problem solved using ADI scheme, the needed
Matlab code is there. it is a 2D problem.

%Solves the 2D diffusion PDE problem
%u_t = D * (u_xx+u_yy) on unit square (0,1)x(0,1) assuming
%Neumann boundary conditions. Uses cell centered grid points
%and used ADI scheme.

--Nasser

[ghasem]

> If you go to
>
> http://12000.org/my_notes/my_matlab_functions/index.htm
>
> and search for the string "ADI " on the page
>
> You'll find one problem solved using ADI scheme, the needed
> Matlab code is there. it is a 2D problem.
>
> %Solves the 2D diffusion PDE problem
> %u_t = D * (u_xx+u_yy) on unit square (0,1)x(0,1) assuming
> %Neumann boundary conditions. Uses cell centered grid points
> %and used ADI scheme.
>
> --Nasser

=======
thank you very much for your attention.but this is 2D.I need a 3D example.
I'm able to simulate 2D grids...
in 3d,I have Divergence problem.and I don't know why this occurs...
my guess is due to Ax=b solving in 3D.
can you direct me?
ghasem...

[Nasser M. Abbasi]

On 4/15/2013 9:11 AM, ghasem wrote:

> thank you very much for your attention.but this is 2D.I need a 3D example.
> I'm able to simulate 2D grids...
> in 3d,I have Divergence problem.and I don't know why this occurs...
> my guess is due to Ax=b solving in 3D.
> can you direct me?
> ghasem...
>

Again, there is no difference between 2D and 3D as far as Ax=b
is concerned.

In 3D, your A matrix will have a different structure, this is
clear. It will also depend on the boundary conditions you have
what the structure is.

You must be not setting up the A matrix correctly in the 3D case.
If you getting wrong solution, then your setup is wrong.

How can one help you on this? You are the only one who can
look at the A matrix?

Why not do a small problem first, to make sure it is correct. Since
with small problem, (say 3 by 3 by 3) you can verified the A
matrix structure by hand.

It will also help you, if you get into the habit of writing a
design document before coding. Most people start coding first,
which is the wrong thing to do.

--Nasser

[ghasem]

> How can one help you on this? You are the only one who can
> look at the A matrix?
>
> Why not do a small problem first, to make sure it is correct. Since
> with small problem, (say 3 by 3 by 3) you can verified the A
> matrix structure by hand.
>
> It will also help you, if you get into the habit of writing a
> design document before coding. Most people start coding first,
> which is the wrong thing to do.
>
> --Nasser

===================
sorry,you are right.
I'm sure that my matrix is correct.AI tested it.
Mr.Abbasi,are you familiar with PML boundary conditions in FDTD?

[Nasser M. Abbasi]

On 4/15/2013 10:41 AM, ghasem wrote:

>are you familiar with PML boundary conditions in FDTD?
>

I am not. We did not study this at school. It was
hard enough just to get dirichlet and Neumann boundary
conditions right.

good luck,
--Nasser

[ghasem]

> I am not. We did not study this at school. It was
> hard enough just to get dirichlet and Neumann boundary
> conditions right.
>
> good luck,
> --Nasser

> ===========================

thank you very much for your attention.

ghasem

[budweiserss]

"ghasem" wrote in message <kkg4am$bb$1...@newscl01ah.mathworks.com>...

> Hi.
> Is there anyone who is familiar with ADI-FDTD method and have matlab code for it?
> I need help...

?????????????????????????????ADI-FDTD???????????ADI-FDTD???????????????
excuse me , i need 3D ADI-FDTD code,thanks a lot!