Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

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

Search the Archive

Re: TransformationFunctions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg102288] Re: TransformationFunctions
  • From: O <kakabomba at gmail.com>
  • Date: Tue, 4 Aug 2009 04:27:57 -0400 (EDT)
  • References: <h46p31$e4g$1@smc.vnet.net> <200907230754.DAA26659@smc.vnet.net>

it works. i think it is good idea to report here what was wrong. I
used function with delayed assignment, and should use function with
delayed assignment and delayed rule. For now i can't fully understand
what is difference, but maybe this information will helpful for
somebody else.

In[1]:= WrongTransformation[l___ ** (a_ + b_) ** r___] := l ** a ** r
+ l ** b ** r
In[2]:= Simplify[a ** (b + c) ** d - a ** b ** d,
TransformationFunctions -> {Automatic, WrongTransformation}]
Out[2]:= -a ** b ** d + a ** (b + c) ** d


In[3]:= ProperTransformation[expr_] := expr /. l___ ** (a_ + b_) **
r___ :> l ** a ** r + l ** b ** r
In[4]:= Simplify[a ** (b + c) ** d - a ** b ** d,
TransformationFunctions -> {Automatic, ProperTransformation}]
Out[4]:= a ** c ** d

thanks


  • Prev by Date: No more memory available.
  • Next by Date: Making your own Definitions using Operators without built in meanings
  • Previous by thread: Re: TransformationFunctions
  • Next by thread: Windonws keyboard shortcut to change between open windows in