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Re: Simplifying complicated expressions

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  • Subject: [mg110452] Re: Simplifying complicated expressions
  • From: Harrie Kraai <hakraai at>
  • Date: Sat, 19 Jun 2010 07:47:08 -0400 (EDT)
  • References: <hudci1$d68$>

I asked a similar question about a year ago,

and got this as the best answer:

leading me to Experimental`OptimizeExpression

But, also look at
perhaps Mathematica is doing something behind the scenes already.


S. B. Gray wrote:
> Suppose I  have a long complex expression in which terms like
> (x^2+y^3-x^2y^2+Sqrt[z3+y2]) (for a simple example) appear many times 
> along with various powers and the reciprocals of it, etc. To make the 
> expression comprehensible and to make the computation faster, I would 
> like to substitute say "f1xyz" for it everywhere it appears. The normal 
> /. and -> substitutions and patterns are not adequate for this. Of 
> course at evaluation time I want to compute f1xyz only once and not have 
> the final formula revert to the original variables. How do I prevent that?
> Also a welcome addition to Mathematica would be the ability to find these 
> repeated expressions automatically and put them in, because doing it 
> manually is very error-prone and slow.
> Tips will be appreciated!
> Steve Gray

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