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

trying to "simplify" very large output

• To: mathgroup at smc.vnet.net
• Subject: [mg83058] trying to "simplify" very large output
• From: "Basjsmit" <basjsmit at wanadoo.nl>
• Date: Fri, 9 Nov 2007 05:11:43 -0500 (EST)

Dear Reader,

When I used Mathematica to solve a certain expression, the output was 
extremely large, somewhere around 10 000 characters. When I looked more 
closely at the output, I noticed certain frases kept repeating. I havent 
found anything in the help, but Im wondering if there is a function that can 
replace those frases with a variable and set that variable once. An example:

t-> -(y z-v x Cos[k]^2-v x Sin[k]^2)/(z^2-x^2 Cos[k]^2-x^2 Sin[k]^2)-1/2 
\[Sqrt]((4 (y z-v x Cos[k]^2-v x Sin[k]^2) ........

becomes:

A = y z-v x Cos[k]^2-v x Sin[k]^2
B = z^2-x^2 Cos[k]^2-x^2 Sin[k]^2
t-> -A / B -1/2 \[Sqrt]((4 A ........

Thanks in advance, Bas

PS: just curious, is there a name for the proces I described above? 

• Follow-Ups:
  • Re: trying to "simplify" very large output
    • From: Daniel Lichtblau <danl@wolfram.com>