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

Re: silly questions?

• To: mathgroup at smc.vnet.net
• Subject: [mg59139] Re: silly questions?
• From: Detlef Müller <demueller at mathematik.uni-kassel.de>
• Date: Sat, 30 Jul 2005 01:25:11 -0400 (EDT)
• References: <200507270526.BAA20063@smc.vnet.net> <dc9vhu$cnk$1@smc.vnet.net> <dcccdb$3cn$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

David Bailey wrote:
>...
>>The cancelled form is much more "complicated", at least as measured  
>>by LeafCount (and Mathematica's default complexity function).
>>
>>So if you want your answer it is better to make ask Mathematica to  
>>make the expression more "complex":
>>
>>
>>Simplify[(x^5 - 32)/(x - 2), ComplexityFunction ->
>>    (1/LeafCount[#1] & )]
>>
>>
>>x^4 + 2*x^3 + 4*x^2 + 8*x + 16
>>
>>But it is of course much more sensible to just use Cancel.
>>
>>Andrzej Kozlowski
>>
>>
>>
> Maybe we need two new Mathematica operations - Complicate and 
> FullComplicate - the trouble is, I guess they would always hang trying 
> to return an infinitely large answer!
> 
> More seriously, a function that presented a range of possible 
> alternatives (together with a command that could achieve the each result 
> directly) might be quite useful.
> 

Prettify may be a better Name ...

For example to eliminate squareroots and in the denominator,
to make denominators real, to achieve as much common
sub-expressions as possible and so on.

Probably it boils down to have a list of penaltys for
subexpressions to expand the ComplexityFunction (and consuming
lots of time).

greetings
   Detlef

• References:
  • silly questions?
    • From: Kent Holing <KHO@statoil.com>