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 Author Comment/Response Stan 06/30/12 12:02pm In Response To 'Re: Re: Maximizing solutions of NDSolve'---------That is strange. I'm using Mathematica at university and it's a version 7. I can't get hold of it until Monday. However I downloaded a trial version of version 8 on my laptop and it indeed found the correct maximum in this example. Nevertheless when I try to calculate what I actually need even v8 gives the wrong result: a[t_] := (1 + 3 t/8)^(2/3) q[q0_, t_] := q0 a[t]^-3 \[Omega][\[Kappa]02_, q0_, t_] := 2 q[q0, t]^(1/2) Sqrt[\[Kappa]02/(2 a[t]^(1/2) q[q0, t]^(1/2)) + Sin[t]^2] s[(\[Kappa]02_)?NumericQ, (q0_)? NumericQ] := NDSolve[{y''[ x] + (4 q[q0, x]) (\[Kappa]02/(2 Sqrt[a[x] q[q0, x]]) + Sin[x]^2) y[x] == 0, y'[0] == 0, y[0] == 0.5}, y, {x, 0, 200}, MaxSteps -> 500000, Method -> {Automatic}, MaxStepFraction -> 1/100] n[\[Kappa]02_, q0_, t_] := \[Omega][\[Kappa]02, q0, t]/ 2 (Abs[y'[t] /. s[\[Kappa]02, q0]]^2/\[Omega][\[Kappa]02, q0, t]^2 + Abs[y[t] /. s[\[Kappa]02, q0]]^2) - 1/2 mueff[\[Kappa]02_, q0_, t_] := 1/(2 t) Log[2 n[\[Kappa]02, q0, t]] ptdata = Table[{\[Kappa]02, First[Re[mueff[\[Kappa]02, (32 Pi)^2, 30.5 Pi]]]}, {\[Kappa]02, 0, 1.5, 0.001}]; int = Interpolation[ptdata] Maximize[{int[x], 0 < x < 1.5}, x] gives {0.121158, {x -> 0.101868}} when the actual global maximum is around x=0.2: In[161]:= int[0.2] Out[161]= 0.126081 URL: ,

 Subject (listing for 'Maximizing solutions of NDSolve') Author Date Posted Maximizing solutions of NDSolve Stan 06/27/12 10:31am Re: Maximizing solutions of NDSolve Stan 06/29/12 08:05am Re: Re: Maximizing solutions of NDSolve Michael 06/29/12 12:31pm Re: Re: Re: Maximizing solutions of NDSolve Stan 06/30/12 12:02pm Re: Re: Re: Re: Maximizing solutions of NDSolve Michael 07/02/12 01:01am Re: Maximizing solutions of NDSolve Stan 07/09/12 07:24am Re: Re: Maximizing solutions of NDSolve Michael 07/10/12 2:30pm Re: Maximizing solutions of NDSolve Forum Modera... 07/14/12 1:27pm
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