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)...
rp /. Part[answer, 2]
0.0920851
Or to extract and save the replacement rule...
rpsol = Part[answer, 2]
{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
djmp at earthlink.net
http://home.earthlink.net/~djmp/
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