NDSolve:StoppingTest in Algebraic Differential Equations

*To*: mathgroup at smc.vnet.net*Subject*: [mg67071] NDSolve:StoppingTest in Algebraic Differential Equations*From*: "ben" <benjamin.friedrich at gmail.com>*Date*: Thu, 8 Jun 2006 04:54:46 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, I discovered a strange behaviour of StoppingTest: * for an ordinary differential equation everything is fine NDSolve[{y'[t] == 1, y[0] == 0}, {y}, {t, 0, 2}, StoppingTest -> {y[t] > 1}] * but even for simple algebraic differential equations, NDSolve[{y'[t] == 1, x[t] == y[t], y[0] == 0}, {x, y}, {t, 0, 2}, StoppingTest -> {y[t] > 1}] I get an error message "Unable to create a NumericalFunction for the expression Hold[{y[t] > 1}] in the method "EventLocator". Any suggestions? Cheers, Ben

**Follow-Ups**:**Re: NDSolve:StoppingTest in Algebraic Differential Equations***From:*bsyehuda@gmail.com