Time dependent ODE's

1

Hi,

I want to solve a problem of time dependent PDEs (reaction equations) with no spatial distribution. Is this any way to do it with Fenics?

Thanks

2

If your "PDE"s only vary with time you’d probably be better served by one of the many ODE integration libraries. Scipy wraps many of these nicely, e.g. odeint.

3

I want to solve them with PDE’s simultaneously, not alone.

4

I would strongly suggest that you state your PDEs, as it is quite hard to give advice without having a minimal example of a strong form of such a problem.

6

I have a system of 5 PDEs and 25 ODEs so lets say we have a more simple problem such as:

U.dt + U.dx^2 = f & f.dt = f^2 + f/3

(I didnt know how to write this in latex form So .dt and .dx are the derivatives with respect to time and space respectively)

7 
$ \frac{a}{b} + c = d $

yields

\frac{a}{b} + c = d

which may help clarify your equations.

8

So lets start again

\frac{du}{dt} + \frac{du}{dx} = f & \frac{df}{dt} = f^2 + \frac{f}{3}

U and f are the uknowns