Simplify and then discretize a set of equations with derivatives and integrals

*To*: mathgroup at smc.vnet.net*Subject*: [mg126709] Simplify and then discretize a set of equations with derivatives and integrals*From*: dr DanW <dmaxwarren at gmail.com>*Date*: Fri, 1 Jun 2012 05:19:03 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <jq25s3$6f6$1@smc.vnet.net>

If you write the capacitor equation in derivative instead of integral form, your equation set is in the form of a Differential-Algebraic Equation (DAE) which I believe NDSolve could solve directly, even if f() is not invertable. Wolfram just released SystemModeler (formerly MathModelica) which is a system for formulating this sort of equation from a representation of a physical system and solving it. In the process, it generates c code of the equation set. If this is a one-time thing, maybe you could download the trial version of SystemModeler and extract the c code from your system. If you are doing this on a regular basis for your project, it might be worth giving SystemModeler a look. Daniel