Re: How to avoid repeated recalculation of the same

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From	Alex Krasnov <akrasnov@cory.eecs.berkeley.edu>
Newsgroups	comp.soft-sys.math.mathematica
Subject	Re: How to avoid repeated recalculation of the same
Date	Sat, 3 May 2014 07:41:54 +0000 (UTC)
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Mathematica makes memoization easy. You can store the result directly in 
the function definition using the idiom f[x_] := f[x] = (...). You can 
then examine the stored results using Information[f].

Alex


On Fri, 2 May 2014, pgeipi10@gmail.com wrote:

> Hi,
>
> I'm doing a calculaton that's purly symbolic (no graphing, numerical integration, etc.).
>
> Suppose I have a function f[x_]:=... that's very complex to build. In fact, f[x] ends up being a manageable expression (about 30 characters) but it takes Mathematica about 30 min to build that expression.
>
> Another function g[] uses the function f[x] and references it many times. I've discovered that g[] actually builds f[x] every time it's referenced which takes 30 minutes each time. Theoretically, Mathematica could build it once and then use the resulting expression every time it's referenced.
>
> So how do I accomplish that? That is, how do I make it build f[x] once and then use the resulting expression when it's needed?
>
> Thanks,
>
>
> Pavel
>

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Re: How to avoid repeated recalculation of the same Alex Krasnov <akrasnov@cory.eecs.berkeley.edu> - 2014-05-03 07:41 +0000

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