Finding root of a function
 

Dear All,

I have just implemented root-finding operations of a function f(x) = 0. If someone is interested, have a look at the SVN - it currently lives in the ODE library.

Enjoy,

Hrv

Hihttp://www.cfd-online.com/Op
 

Hihttp://www.cfd-online.com/OpenFOAM_D...part/happy.gif

I am about to be solving 4 sets of non-linear equations on each face on certain boundary-patches. As far as I can see, the function implemented by Hrv is for 1 equation!?!
Is there anywhere in OF implemented some kind of solver for N non-linear set of equations?
If not, could you please suggest to me a suitable open-source implementation, preferable in C++.

Best regards,

Niels

P.S. Thank you for an utterly fantastic workshop.

Dear all,

Has anyone been able to use the BisectionRoot, or RiddersRoot or the NewtonSecant methods in the "findRoot" folder on the svn?

Say I want to solve for x in

0 = -3 + 4(Exp(2x)-Exp(3x))

I have the findRoot folder in src/ODE and added the path to my /make for the solver.

How, then do I implement any of the findRoot methods to get x?

Best regards,
Sandra

I fixed my issue on this link : http://www.cfd-online.com/Forums/ope...ng-method.html

Hi guys;

I guess my post is best fitted to this thread.

I am trying to solve 2 non-linear equations simultaneously using Newton-secant method.

As Niels had asked the "findRoot" is tested over one equation. How can I couple and use two equations in order to find the solution roots? Any example case already implemented in Foam-extend?

Additionally is it possible to write the number of iterations taken in order to reach the tolerance?

Thanks,
Saideep