InterpolatingFunction in NDSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg21640] InterpolatingFunction in NDSolve*From*: eborzova at my-deja.com*Date*: Tue, 18 Jan 2000 02:35:23 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi everybody. My question could be simple, but I just can't figure it out. I need to use InterpolatingFunction inside yet another function (Derivs) that is rhs for NDSolve (please refer to the code below). The problem is that if my rhs "Derivs" has some sort of conditional logic (e.g. "If"), then it stops working (see a comment with Return[sss[x]]). Any help/hints/feedback are greatly appreciated! Thanks. Elena. Clear[sss]; Clear[solution]; Clear[sol2]; solution = NDSolve[{Derivative[1][y][x]==-10*y [x], y[0] == 1}, y,{x, 0, 0.5}] sss = (y[x] /. solution[[1]])[[0]]; (* interpolating function seems to be ok: can Plot it *) Plot[sss[t], {t, 0, 0.5}]; Derivs[y_, x_] := Block[{}, (* uncomment below to make it work *) (* Return[sss[x]]; *) If[x < 0.25, Return[sss[x]], Return[-sss [x]]]; Print["Ooops!!!!"]; Abort[]; ]; sol2 = NDSolve[{Derivative[1][y][x] == Derivs[y, x], y[0] == 0}, y,{x, 0, 0.5}] Plot[Evaluate[y[x] /. sol2], {x, 0, 0.5}]; Sent via Deja.com http://www.deja.com/ Before you buy.