Re: Re: Eliminating Annoying Minus Signs

*To*: mathgroup at smc.vnet.net*Subject*: [mg58780] Re: [mg58770] Re: [mg58756] Eliminating Annoying Minus Signs*From*: yehuda ben-shimol <bsyehuda at gmail.com>*Date*: Mon, 18 Jul 2005 03:21:18 -0400 (EDT)*References*: <20050717191307.ZPJB19733.lakermmtao05.cox.net@smtp.east.cox.net>*Reply-to*: yehuda ben-shimol <bsyehuda at gmail.com>*Sender*: owner-wri-mathgroup at wolfram.com

correct, thanks for the correction. yehuda On 7/17/05, Bob Hanlon <hanlonr at cox.net> wrote: > The attributes are documented, use ?? to see them: > > ??Numerator > > ??Denominator > > > Bob Hanlon > > > > > From: yehuda ben-shimol <bsyehuda at gmail.com> To: mathgroup at smc.vnet.net > > Date: 2005/07/17 Sun PM 01:03:15 EDT > > Subject: [mg58780] [mg58770] Re: [mg58756] Eliminating Annoying Minus Signs > > > > Hi David, > > Although not documented it seems that both Numerator and Denominator > > are listable so > > (-Numerator[#])/(-Denominator[#])&[test] > > or > > test//(-Numerator[#])/(-Denominator[#])& > > will do the same without mapping. > > yehuda > > > > On 7/17/05, David Park <djmp at earthlink.net> wrote: > > > Yehuda, > > > > > > Thanks. That seems pretty good. > > > > > > We could turn this into a routine that could be mapped onto terms more > > > generally in an expression. > > > > > > NDSignSwitch = (-Numerator[#])/(-Denominator[#]) &; > > > > > > test = {-((2*x)/(-1 + z)), -((2*y)/(-1 + z)), -1}; > > > > > > NDSignSwitch /@ test > > > {(2*x)/(1 - z), (2*y)/(1 - z), -1} > > > > > > David Park > > > djmp at earthlink.net > > > http://home.earthlink.net/~djmp/ > > > > > > > > > > > > From: yehuda ben-shimol [mailto:bsyehuda at gmail.com] To: mathgroup at smc.vnet.net > > > > > > Hi David, > > > How about > > > (- Numerator /@ test)/(- Denominator /@ test) > > > this is not error prone. > > > I'm almost certaint that there is more efficient way of doing this. > > > I'll try to find it later > > > regards > > > yehuda > > > > > > > > > > > >