Re: Calculations with Interpolating Functions
- To: mathgroup at smc.vnet.net
- Subject: [mg88532] Re: Calculations with Interpolating Functions
- From: dh <dh at metrohm.ch>
- Date: Wed, 7 May 2008 07:10:48 -0400 (EDT)
- References: <fvpcqn$mhn$1@smc.vnet.net>
Hi Joao,
you can always re-interpolate a function of an interpolating function.
Therefore, write your function Sin[...] as an interpolationg function.
Here is an example:
t=FunctionInterpolation[x^2,{x,0,2}];
ts=FunctionInterpolation[Sin[t[x]],{x,0,2}];
Integrate[ts[x],{x,0,2}]
hope this helps, Daniel
João Paulo Casquilho wrote:
> Hi
>
>
>
> I obtain an Interpolating function as a solution of a differential equation
> with the command NDSolve, lets call it =93solution=94, which gives x(t). Next I
> want to use this solution for further calculations. With the commands
> =93result=Evaluate[x(t)/. First[solution]]=94 or =93result= x(t)/.solution,
> {t,0,tmax}=94 I do the plot x(t) without any problems. Now, with version 5.2 I
> manage to integrate x(t) or linear functions of it. But when I try to
> integrate non linear functions of x(t), like x(t)^2 or Sin[x(t)] (which is
> what I want), Mathematica is unable to give a numerical result, all I get
> is an integral saying that there is an InterpolatingFunction in the
> integrand. With Mathematica 6 the linear integration does not work either.
>
> Any help would be appreciated.
>
>
>
> Best Regards
>
>
>
> Joao Paulo
>
>
>