Re: Symbolic complex conjugation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg89967] Re: Symbolic complex conjugation?*From*: dh <dh at metrohm.ch>*Date*: Wed, 25 Jun 2008 06:28:41 -0400 (EDT)*References*: <g3q7vb$aus$1@smc.vnet.net>

Hi, pattern matching can sometimes be a bit tricky. But it jusually helps to look at the expression using FullForm. You will see that in the first expression we have Complex[0,1] what is eqaul to I, but in the second expression we have Complex[0,-1] what equals -I. Therefore, you should replace -I->I. hope this helps, Daniel AES wrote: > I'm sorry, but I just don't understand why the following test case works > just fine: > > [In copying it, I've substituted "Isymbol" for the \[ImaginaryI] that > actually appears in the Out[] cells.] > > In[202]:= eqna={a+I b==0}; > solna=Solve[eqna,b]; > b=b/.solna[[1]]; > bStar=b/.{I->-I}; > {b, Star} > > Out[205]={ -Isymbol a, Isymbol a } > > but the actual calculation that prompted the test case doesn't: > > In[206]:= eqnp={((dwa/2)+I(w-wa))p-I (kappa/(2 w))dN e==0}; > solnp=Solve[eqnp,p]; > p=p/.solnp[[1]]; > pStar=p/.{I->-I} > > Out[208]= { (dN e kappa)/(w (-Isymbol dwa+2 w-2 wa)), > (dN e kappa)/(w (-Isymbol dwa+2 w-2 wa)) } > > And actually, I guess my real concern is not understanding "how it > happens" -- but more "how it can happen" that Mathematica can do > something this potentially damaging to some innocent user. > -- Daniel Huber Metrohm Ltd. Oberdorfstr. 68 CH-9100 Herisau Tel. +41 71 353 8585, Fax +41 71 353 8907 E-Mail:<mailto:dh at metrohm.com> Internet:<http://www.metrohm.com>