How to pass initial conditions to IDA methods via NDSolve?
- To: mathgroup at smc.vnet.net
- Subject: [mg121819] How to pass initial conditions to IDA methods via NDSolve?
- From: GRW <georgwalther at gmail.com>
- Date: Tue, 4 Oct 2011 01:30:10 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
New to Mathematica so this might be gibberish. I'm trying to integrate numerically a PDE system. NDSolve complains saying this: "NDSolve::icfail: Unable to find initial conditions that satisfy the residual function within specified tolerances. Try giving initial conditions for both values and derivatives of the functions." Now I've figured out how to get numerical estimates for some of the derivatives in my PDE system (using FindRoot there). However, if I add these conditions to my preexisting list of initial conditions and boundary conditions, Mathematica complains that there are too many boundary and/or initial conditions: "NDSolve::ivone: Boundary values may only be specified for one independent variable. Initial values may only be specified at one value of the other independent variable" It seems as if IDA was selected automatically as "Method" option of NDSolve and IDA does not seem to allow for initial conditions passed to it. I've tried using Method option "Shooting" (because this one seems to allow for initial conditions passed), however NDSolve isn't too fond of that one either: "NDSolve::nodae: The method NDSolve`Shooting is not currently implemented to solve differential-algebraic equations. Use Method -> Automatic instead." Any advice greatly appreciated!