Re: A way around the limitations of Re[] and Im[]

*To*: mathgroup at smc.vnet.net*Subject*: [mg51125] Re: A way around the limitations of Re[] and Im[]*From*: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>*Date*: Tue, 5 Oct 2004 04:37:15 -0400 (EDT)*Organization*: Uni Leipzig*References*: <cjr8lg$opp$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi, a Real is the head of floating point numbers and it is not a good idea to attatch a function definition to it. And look what ComplexExpand[Re[a + I*b]] does. Regards Jens "Carlos Felippa" <carlos at colorado.edu> schrieb im Newsbeitrag news:cjr8lg$opp$1 at smc.vnet.net... > As you know, Re[expr] and Im[expr] are left unevaluated when expr is > not numeric. I had good luck in simple cases with the following > substitution trick: > > Real[c_]:=c/.I->0; Imag[c_]:=(c-Real[c])/.I->1; > > Do you see any problem with these definitions? >