Can we solve ODEs as a nested function while using pdepe?

Hi,

I would like to know how to solve ODEs as a nested function or some other way in my pdepe scripts? So lets say this below:

function [c,f,s] = pdex1pde(x,t,u,DuDx)
c = pi^2;
f = DuDx;
s = 0;
end

How do I add a nested function to alter the source s? I know I can do it within the function above as well but I would like to make a more complex function elsewhere and introduce it at s as a sum or subtraction.

Hope I am making some sense.

[Torsten]

Call a function within pdex1pde:

s = fun_s(...)

[Hashim]

So, I guess you mean to say do something like:

function [c,f,s] = pdex1pde(x,t,u,DuDx)
    c = pi^2;
    f = DuDx;
    s = p; 
    function p = fun_s(t, y)
        p=y(1)*y(2);
        [t,y]=ode15s(fun_s, tspan, y0);
    end
end

But isn't something like this possible?

function [c,f,s] = pdex1pde(x,t,u,DuDx)
    p = fun_s(t, y)
    c = pi^2;
    f = DuDx;
    s = p;
end

function p = fun_s(t, y)
    p=y(1)*y(2);
    [t,y]=ode15s(fun_s, tspan, y0);
end

[Torsten]

Please state the equations you are trying to solve.

As it seems, you want to solve an ODE in each grid point of the PDE and assign the solution of this ODE to "s".

But what inputs of the PDE are needed to solve the ODE ?

[Hashim]

Inputs required to solve the ODE are given within the parent function. And yes I just want a separate function to solve the ODE at the grid point. Then add or subtract that solution from s.

The system of equations is given here. Now I have been able to solve these what I am thinking is if I want to add/subtract another source term I want to be able to do it as a separate nested function within the script.

[Torsten]

From pdex1pde, call a function in which you provide the necessary data to solve the ODE, solve the ODE and return the result to pdex1pde. What's the problem ? And where is the ODE in the set of equations you gave the link to ?

Answer 1

[Rishita]

sol = pdepe(m,pdefun,icfun,bcfun,xmesh,tspan)

sol = pdepe(m,pdefun,icfun,bcfun,xmesh,tspan,options)

[sol,tsol,sole,te,ie] = pdepe(m,pdefun,icfun,bcfun,xmesh,tspan,options)

Went through this https://in.mathworks.com/matlabcentral/answers/1760335-can-we-solve-odes-as-a-nested-function-while-using-pdepe?s_tid=srchtitle

[Hashim]

I don't get how this is related. I know how to use pdepe by this point.