Re: distance function
- To: mathgroup at smc.vnet.net
- Subject: [mg68728] Re: [mg68686] distance function
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Thu, 17 Aug 2006 04:18:35 -0400 (EDT)
- Organization: Mathematics & Statistics, Univ. of Mass./Amherst
- References: <200608160736.DAA06170@smc.vnet.net>
- Reply-to: murray at math.umass.edu
- Sender: owner-wri-mathgroup at wolfram.com
If you don't mind an "extravagant" solution -- one that is conceptually
simple and short but is probably inefficient due to redundant
calculations -- then this works, I believe:
d[{p_, q_}] := Norm[p - q]
allDistances[pts_] := Union[Flatten[Outer[d, pts, pts]]]
dimmechan at yahoo.com wrote:
> In the book of Gaylord et al. (1996) there is one exercise which asks
> (see page 113)
>
> "Given a list of points in the plane, write a function that finds the
> set of all distances
> between the points."
>
> Although there is one solution, that solution makes use of the Table
> and Length commands.
>
> Is it a way to define the same function using Higher-Order functions
> like Outer, MapThread etc?
>
> Thanks in advance for any help.
>
>
--
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
- References:
- distance function
- From: dimmechan@yahoo.com
- distance function