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Re: FullSimplify in functions

• To: mathgroup at smc.vnet.net
• Subject: [mg82601] Re: FullSimplify in functions
• From: Szabolcs Horvát <szhorvat at gmail.com>
• Date: Fri, 26 Oct 2007 05:14:41 -0400 (EDT)
• References: <ffpq3s$lbu$1@smc.vnet.net>

Michael Mandelberg wrote:
> What is the best/proper way to incorporate FullSimplify[ ] into a
> function definition in such a way that the FullSimplify[ ] executes
> only once instead of each time the function is called, i.e. it is
> "compiled", though I'm not sure this is the same thing as the
> Mathematica Compile[ ] function.
> 

OK, I think I misunderstood what you meant.  If the expression 
FullSimplify[] will be applied to does not depend on the argument of the 
function, then simply use Set[] instead of SetDelayed[].

In[1]:= f[x_] = Simplify[Sin[x]^2 + 2 Cos[x]^2]
Out[1]= 1/2 (3 + Cos[2 x])

In[2]:= ?f
Global`f
f[x_]=1/2 (3+Cos[2 x])

In[3]:= g[x_] := Simplify[Sin[x]^2 + 2 Cos[x]^2]

In[4]:= ?g
Global`g
g[x_]:=Simplify[Sin[x]^2+2 Cos[x]^2]

Is this what you meant?

Szabolcs

P.S. Still, compilation is something *completely* different from 
evaluating an expression before assigning it to something.  Read the doc 
page tutorial/CompilingMathematicaExpressions to understand it.