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
>
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