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 > > > > >