Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Re: Union - simple question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg49097] Re: [mg49086] Re: Union - simple question
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Thu, 1 Jul 2004 05:25:44 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

On 30 Jun 2004, at 18:34, Maxim wrote:

> Another point is that SameTest->Automatic is something rather obscure,
> it is not the same as SameTest->SameQ or SameTest->Equal:
>
> In[2]:=
> Union[{1`20, 1`30}]
> Union[{1`20, 1`30}, SameTest -> SameQ]
>
> Out[2]=
> {1.0000000000000000000, 1.00000000000000000000000000000}
>
> Out[3]=
> {1.0000000000000000000}
>
> Definitely there are grounds for confusion.
>
> Maxim Rytin
> m.r at inbox.ru
>
As far as I know, the option value Automatic is never exactly equal to 
any other built-in option value, and why should it be? For example, the 
default value Automatic for the option ComplexityFunction in Simplify 
often but not always coincides with LeafCount. Here is an example from 
a past MathGroup posting:


Simplify[-4*(16 + 4*L^2*(-1 + 3*u^2))]


-4*(4*(3*u^2 - 1)*L^2 + 16)


Simplify[-4*(16 + 4*L^2*(-1 + 3*u^2)),
   ComplexityFunction -> LeafCount]


L^2*(16 - 48*u^2) - 64



Andrzej Kozlowski
Chiba, Japan
http://www.mimuw.edu.pl/~akoz/


  • Prev by Date: RE: function IF with several equality conditions
  • Next by Date: Re: function IF with several equality conditions
  • Previous by thread: Re: function IF with several equality conditions
  • Next by thread: Re: Appropriate codec for playing Mathematica generated .wav files