MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Operations on InterpolatingFunction



Hi Porscha,

obviously there are only rules to integrate InterpolatingFunctions but 

none for functions of InterpolatingFunctions.

You could add such rules, but it is easier to write the "function of a 

InterpolatingFunction" as an InterpolatingFunction.

E.g. your case:

ifun2 = FunctionInterpolation[ifun[x]^2, {x, 0, Pi}]

Now you can integrate ifun2:

Integrate[ifun2[t], t]

hope this helps, Daniel





Porscha Louise McRobbie wrote:

> Hi,

> 

> Solving a simple differential equation:

> ifun = First[

>    u /. NDSolve[{u''[t] + u[t] == 0, u[0] == 0, u'[0] == 1},

>      u, {t, 0, \[Pi]}]]

> 

> returns the InterpolationFunction object, as expected. I can integrate  

> this function (and obtain another InterpolatingFunction to be plotted,  

> etc.) by:

> 

> Integrate[ifun[t], t]

> 

> 1. Why doesn't the following produce an InterpolatingFunction in the same way?

> 

> Integrate[ifun[t]^2, t]

> 

> 2. How can I normalize the solutions found using NDSolve?  

> Norm[ifunt[t]] doesn't work...

> 

> Thanks for any help.

> 

> 

> 

> 

> 

> 




  • Prev by Date: Re: What should be a simple task....
  • Next by Date: Re: Extracting contour values from ContourPlot
  • Previous by thread: Operations on InterpolatingFunction
  • Next by thread: Re: Operations on InterpolatingFunction