NDSolve Errors: icfail and ntdv

*To*: mathgroup at smc.vnet.net*Subject*: [mg77226] NDSolve Errors: icfail and ntdv*From*: ehicks <ehicks at uchicago.edu>*Date*: Wed, 6 Jun 2007 06:43:37 -0400 (EDT)

Hi, I am trying to solve a set of equations with NDSolve. The problem is no matter what I do, I keep getting errors of various kinds. I've used NDSolve successfully in the past, so I am starting to wonder if maybe this set of equations just doesn't have a solution. My set is diffeo-alegbraic, so at first I got the NDSolve::icfail error. I tried to circumvent that by taking the derivative of one of the equations. Then I got the NDSolve::ntdv error. So I tried SolveDelayed->True, which just got me right back to the icfail error. Does anyone have any ideas on ways to circumvent these errors? Thanks! -Elizabeth See the Mathematica File at: http://www.tarzia.selfip.com/~elizabeth/fullplumemodel1.nb The text of the errors is: NDSolve::icfail: Unable to find initial conditions which satisfy the residual function within specified tolerances. Try giving initial conditions for both values and derivatives of the functions. NDSolve::ntdv: Cannot solve to find an explicit formula for the derivatives. Consider using the option setting SolveDelayed->True.