Re: solve question/simplify question

• To: mathgroup at smc.vnet.net
• Subject: [mg55572] Re: solve question/simplify question
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Wed, 30 Mar 2005 03:21:05 -0500 (EST)
• Organization: Uni Leipzig
• References: <d2341s\$lgg\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

solving a linear system of equations of dimension
n is
a n^2 process and for nonlinear systems it depends
on the
system. So a larger system will need more time.

To impove the memory usage you may substitute
common terms
in your expression. But this depend on the
detailed form of
the expression .

Regards
Jens

"Paul Schneider" <paulibaer at uboot.com> schrieb im
Newsbeitrag news:d2341s\$lgg\$1 at smc.vnet.net...
> Hi,
>
> I have a list called equns of linear equations
> which are independent of
> each other. The according variables are in a
> list called params. I solve
> the equations into a list called sol using
>
> sol = Solve[equns, params];
>
> Can I expect the solution procedure to be faster
> or in favor of memory
> usage if I iterate through the elements of the
> lists and solve for each
> equation separately? Same question goes for
> Simplify.
>
> I don't want to try and find out myself because
> I have noticed big
> differences in running times with Mathematica
> and I am not sure how to
> test for improved speed. The equations are
> enormous and I don't know in
> advance how they look like, so I can't use the
> linear algebra routines.
>
> My second question goes to memory management.
> Even though I have lots of
> memory it gets maxed out pretty quickly when I
> use Simplify, or
> FullSimplify on the solutions of those huge
> equations. So I tried to get
> rid of expressinos that are not needed anymore
> by
>
> Clear[var]
> or
> var = .
>
> as is proposed in the help files. I also tried
> Share[ ]. But it doesn't
> seem to do anything. How can I improve this
> situation.
>
> Thank you,
>
> Paul
>

```

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