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Robin condition is the boundary condition which combines the Dirichlet and Neumann condition at the same boundary.

For example:

At the boundary x = 0 to 2: I want to apply

u[x] = 0 for x = 0 to 1 and du/dx = 0 for x = 1 to 2.

I think one of the possible approach is reformulate the PDE discretization using the finite difference method, and manual apply the Robin boundary condition on the systems of ODE.

Could we trick that for DSolve, NDSolve?

user21
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Nam Nguyen
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    THere is a notebook here that has an example http://www.ekayasolutions.com/UCDMath/PDEApplications.php (using finite difference). – Nasser Feb 20 '14 at 13:21
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    btw, I just looked at your B.C. (before I just saw you mentioned Robin BC in title.) the B.C. you show is not Robin. In Robin, BOTH Dirichlet and Neumann exist on the same region. What you have above is really a mixed B.C. and not Robin. btw, wait a little bit for Version 10, hopefully it will have finite elements support finally and one can expect to solve these problems much easier with FEM new API – Nasser Feb 20 '14 at 14:03
  • Thank you Nasser. I also look at your demonstration. It's great. Are you sure that FEM will be implemented in v10? :) For this piece-wised boundary condition do you know how to trick Mathematica? – Nam Nguyen Feb 20 '14 at 14:09
  • IMTEK FEM is also great but few peoples use it. I dont understand why. – Nam Nguyen Feb 20 '14 at 14:12
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    I am just guessing really that FEM will be in V 10. Only someone in WRI would know for sure. But if you type ?"NDSolveFEM*" you'll see all the hooks there. See http://mathematica.stackexchange.com/questions/3292/what-is-ndsolvefem (its been there since V8, so one would expect it is ready by now :) – Nasser Feb 20 '14 at 14:12
  • IMTEK is great, but it hasn't been update for a long time, some of its functions are not compatible with current mma version now... – Silvia Feb 20 '14 at 16:00
  • @Nasser I didn't have high hopes based on that context, as you say it's been there for a long time. But take a look under Geometry here. It looks encouraging. Most of it is missing though. – Szabolcs Feb 20 '14 at 16:56
  • @Silvia , which fe tools are recommaned now (sure in MMA)? – ABCDEMMM Jan 28 '19 at 10:21
  • @ABCDEMMM Finite element method is built-in now. Check the documentations for details. – Silvia Feb 04 '19 at 07:37

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