       RE: Using a Result from NMinimize

• To: mathgroup at smc.vnet.net
• Subject: [mg49384] RE: [mg49367] Using a Result from NMinimize
• From: "David Park" <djmp at earthlink.net>
• Date: Sat, 17 Jul 2004 06:38:49 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Greg,

Let's say that you have saved the output of NMinimize in answer.

answer = {0.0817747, {rp -> 0.0920851}};

Now all you have to do is use Part to extract the part of the answer that
you want. For example, to extract and use the replacement rule(s)...

0.0920851

Or to extract and save the replacement rule...

{rp -> 0.0920851}

You can now substitute in any expression. For example...

rp^2 + Cos[rp];
% /. rpsol
1.00424

You could Set rp directly with

rp = Part[answer, 2, 1, 2]

and then any expressions will be automatically evaluated.

rp^2 + Cos[rp]
1.00424

But then rp is no longer available as a manipulable symbolic variable. If
you try to revaluate NMinimize, rp will now have a value and it won't work.
So many people prefer to stay with the substitution rule and avoid using
Set.

David Park

From: Gregory Lypny [mailto:gregory.lypny at videotron.ca]
To: mathgroup at smc.vnet.net

Hello Everyone,

When I use NMinimize, it gives the result as the minimum value of the
function and the value of the argument that gets us there, for example,

{0.0817747, {rp -> 0.0920851}}.

How can I access the second element, that is, the value of the
argument, so that I can use in other computations.  In other words, I
want get at 0.0920851 and strip away the rp ->.

Regards,

Greg

```

• Prev by Date: RE : How to extract a solution from Mathematica's answer to "Solve"
• Next by Date: Re: DeleteCases : several at once, conditions
• Previous by thread: Re: Using a Result from NMinimize
• Next by thread: Re: Using a Result from NMinimize