Re: Re: Bug Report - Two numerical values for a same variable
- To: mathgroup at smc.vnet.net
- Subject: [mg54322] Re: Re: Bug Report - Two numerical values for a same variable
- From: "Steve Luttrell" <steve_usenet at _removemefirst_luttrell.org.uk>
- Date: Thu, 17 Feb 2005 10:30:42 -0500 (EST)
- References: <00ed01c512b0$2f242850$6400a8c0@Main> <firstname.lastname@example.org> <200502150438.XAA29728@smc.vnet.net> <email@example.com>
- Sender: owner-wri-mathgroup at wolfram.com
I am also uneasy about Complex and Rational being atomic. The only reason I
can think of is that computational efficiency might prefer these to be
You can do the following to extract the parts of a Rational:
Analogously, Re and Im can be used to extract the "parts" of a Complex.
"Murray Eisenberg" <murray at math.umass.edu> wrote in message
news:cv0953$jbg$1 at smc.vnet.net...
> The manipulations below are precisely what's so confusing about Rational
> objects (and Complex objects) being atoms. If
> 1/2 /. Rational[x_, 2] -> Rational[x, 7]
> works, then why not the following?
> Part[Rational[1, 2], 2]
> I can "believe" that integers and reals (and maybe strings) are atoms;
> but believing that rationals and complex numbers are atoms is a hard
> thing to swallow!
> This has always bothered me -- and hence given me trouble trying to, um,
> rationalize this to students when I've taught Mathematica.
> Scott Hemphill wrote:
>> DrBob <drbob at bigfoot.com> writes:
>>>That explains it, but only in the sense that "things fall down" is a
>>>theory of gravity. Why should Rationals be atomic, for goodness sake? And
>>>how did I use Mathematica all this time without hearing about it?
>> In:= FullForm[1/2]
>> Out//FullForm= Rational[1, 2]
>> In:= 1/2 /. Rational[x_,2] -> Rational[x,7]
>> Out= -
> Murray Eisenberg murray at math.umass.edu
> Mathematics & Statistics Dept.
> Lederle Graduate Research Tower phone 413 549-1020 (H)
> University of Massachusetts 413 545-2859 (W)
> 710 North Pleasant Street fax 413 545-1801
> Amherst, MA 01003-9305
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