Re: vector integration

• To: mathgroup at smc.vnet.net
• Subject: [mg35073] Re: [mg35052] vector integration
• From: Andrzej Kozlowski <andrzej at platon.c.u-tokyo.ac.jp>
• Date: Mon, 24 Jun 2002 03:20:56 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Integrate and NIntegrate do actually work with vector valued functions,
e.g:

f[x_] := {x^2, x^3}

In[2]:=
NIntegrate[Evaluate[f[x]],{x,0,1}]

Out[2]=
{0.333333,0.25}

It is not clear from your description why this does not work in your
case. Perhaps you should post your actual example or at least a
mini-version that has the same essential features.

Andrzej Kozlowski

Toyama International University
JAPAN
http://platon.c.u-tokyo.ac.jp/andrzej/

On Friday, June 21, 2002, at 12:54  PM, Michael Bechmann wrote:

> hello everybody,
> i am facing a problem in the numerical integration of a vector-valued
> function using Mathematica.
> as the result of some operation on the variable x  defined by  f[x_]=...
> i get a list of numbers {f1,f2,f3,...,fn} each of which depends on the
> variable x.
> the bad point is that the fi can not be evaluated one by one. for some
> chosen value of x i can only calculate the whole list of the fis.
> now i need to integrate each of the fis over x. of course i could
> intgrate each list element separately using NIntegrate:
>
> Fi=NIntegrate[f[x][[i]],{x,x1,x2}]
>
> but since the evaluation of the list f[x] is very time consuming i would
> like to somehow integrate the whole list at once which is not possible
> with NIntegrate.
>
> did anybody encounter this problem, too? does anybody know a useful
> package  or any solution?
>
> thanks.
>
>
> --
> Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
>
>
>
>

```

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