Re: Why IntervalBisection can't operate on InterpolatingFunction

*To*: mathgroup at smc.vnet.net*Subject*: [mg53766] Re: Why IntervalBisection can't operate on InterpolatingFunction*From*: "Astanoff" <astanoff at yahoo.fr>*Date*: Thu, 27 Jan 2005 05:40:58 -0500 (EST)*References*: <ct4gg2$aqi$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

An example of what I would do if I were you : In[1]:= sol=NDSolve[y''[x] == -y[x] && y[0] == 0 && y'[0] == 1.,y[x],{x,0,30}] Out[1]= {{y[x] -> InterpolatingFunction[{{0.,30.}},<>][x]}} In[2]:= t=Table[FindRoot[(y[x]/.sol[[1]]) == 0,{x,u}],{u,0,30,0.1}]; In[3]:= Union[t,SameTest -> (Abs[(x/.#2)-(x/.#1)] < 10^-5&)] Out[3]= {{x -> -0.007339502277553871}, {x -> -3.623051082982261*^-21}, {x -> 3.1415927483622084}, {x -> 6.283185408412805}, {x -> 9.4247780931598}, {x -> 12.566370764359306}, {x -> 15.707963453833294}, {x -> 18.849556119270865}, {x -> 21.991148799043714}, {x -> 25.132741498078957}, {x -> 28.274334175842473}, {x -> 31.43186632880639}, {x -> 33.01000282339253}} v.a.