how to specify initial conditions on a given subdomain, for a pde

Hi there, I am trying to solve a parabolic pde with a particular geometry. I don't know how to specify the initial condition on a particular subdomain. For the moment I am using the GUI pdetool, but I'm also interested in command-line solutions.

Thanks to everybody !

Alessio

[pradeep]

Hey I also have the same problem as you had (i.e. I want to specify initial condition for a particular subdomain and not to the whole geometry).So please tell me if you got the answer to our problem. Thanks in advance :)

Answer 1

[Bill Greene]

Alessio,

The PDE Toolbox allows you to specify initial conditions as a MATLAB expression or by defining a user-written MATLAB function. The MATLAB expression can be a function of the spatial variables x and y. If, instead, you write a MATLAB function, it takes two parameters, x and y.

In either case, the expression (or function) would return a value for the initial condition based which subdomain the x,y location is in.

If using the pdetool GUI, the expression or function name is entered in the Initial solution box of the Solve parameters dialog box. If using the parabolic() or hyperbolic() functions directly, the expression or function name is passed as a string variable, u0 for both parabolic and hyperbolic and ut0 for hyperbolic.

Bill Greene