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