Hold and Simplify
- To: mathgroup at smc.vnet.net
- Subject: [mg77143] Hold and Simplify
- From: "news.inode.at" <paul.g.schneider at google.com>
- Date: Tue, 5 Jun 2007 06:25:56 -0400 (EDT)
Hi,
I would like to change Exponential functions of sums to products of
exponential functions. From reading postings from the year 2004 I tried
the following:
f[Exp[x_ + y_]] := Exp[x + y] /. Exp[a_ + b_] :> HoldForm[Exp[x]*Exp[y]];
Simplify[Exp[a + b], TransformationFunctions -> f]
Unfortunately this gave me
Exp[a+b]
I had more luck with
rule = {Exp[a_ + b_] -> f[Exp[a + b]]}
ReplaceRepeated[Exp[a + b], rule]
which gave me Exp[a]Exp[b]
Trying
ReplaceRepeated[Exp[a + b + c], rule]
gave me:
Exp[a]Exp[b+c]
Why doesn't the TransformationFunction trick work? Why does
ReplacedRepeated stop?
My ultimate goal would be the following: (I need to transfer large
formulae into C code and would like to avoid use of exponential function
as much as possible)
myreplacelist={Exp[var1]->expvar1, Exp[var2]->expvar2}
myformula=Exp[2 var1 - 3 var2 + a * Exp[var1]];
ultimate rule applied to my formula gives:
expvar1 * expvar1 / (expvar2 * expvar2 * expvar2) * Exp[a expvar1]
Thanks for your time!
best,
Paul
- Follow-Ups:
- Re: Hold and Simplify
- From: Andrzej Kozlowski <akoz@mimuw.edu.pl>
- Re: Hold and Simplify