Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2010

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

Search the Archive

Re: How to disable Integrate[] ?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg109483] Re: How to disable Integrate[] ?
  • From: "Christoph Lhotka" <christoph.lhotka at univie.ac.at>
  • Date: Thu, 29 Apr 2010 02:53:27 -0400 (EDT)

Hello,

if it is a matter of Simplifiy use

Simplifiy[...., ExcludedForms->{Integrate[__,_]}]

if you want prevent Mathematica trying to evaluate an integral I usually
change the head to something, which Mathematica will not try to evaluate:

IntegrateH[expr,vars]

Once you found a simpler form of expr, or something else, you can again
use something like

... /. IntegrateH->Integrate

to tell Mathematica for trying it again.

Christoph



On Mi, 28.04.2010, 08:00, slawek wrote:
> The input line is:
>
> In[1]:= somethingComplicated *
> Integrate[somethingEvenMoreComplicated,{variable,a,b}] //. rules
>
> Simplify takes about 5 minutes. And, surprise surprise, the result is
> still
> an Integrate[somethingElse,{anothervariable,p,q}]
>
> It is not so bad, the integral is obviously too compound for Mathematica
> (and for me), nevertheless the the reason to use Simplify or FullSimplify
> is
> not to calculate Integrate[], but rather to transform
> somethingEvenMoreComplicated into somethingElse.
>
> Is any easy way to force Mathematica to give up simplifing Integrate? And
> obviously to transform all other parts of an expression, including these
> parts which are integrated?
>
> HoldForm nearly do this job, but "freeze" all parts of the equation. It is
> possible to "hold" only Integrate function?
>
> (I tried replace Integrate by dummyIntegrate, i.e. an undefined function.
> But it does not work quite well.)
>
> slawek
>
>
>
>
>



  • Prev by Date: Re: Why Return[] does not work?
  • Next by Date: Re: InputField Rounding Problem
  • Previous by thread: How to disable Integrate[] ?
  • Next by thread: Re: How to disable Integrate[] ?