Re: [R] Question about Constraint Optimization

2008-06-27 Thread Hans W. Borchers

Have a look at the following R-help entry in March:

https://stat.ethz.ch/pipermail/r-help/2008-March/157249.html

with an example of how to use 'optim' with equality constraints. This will
also work with no gradient and 'method="SANN" '.

In my experience, solutions received with "SANN" were not too convincing. If
you look for 'evolutionary computing' approaches, Differential Evolution as
in 'DEoptim' -- though slower -- will give more accurate results in general. 

Hans Werner Borchers


HNie wrote:
> 
> Dear All,
> 
> I am having trouble in using R function "constrOptim" to do constraint 
> optimization. It seems that "constrOptim" calls function "optim" when it 
> does the optimization, and "optim" allows us to set "method" to be "SANN" 
> if we want to use simulated annealing. In "optim", the function allows us 
> to set gradient to be NULL when we treat "method" as "SANN". But in 
> "constrOptim", the function does not allow us to set gradient as "SANN" if 
> we set "method" to be "SANN". I am just curious about it.
> 
> I just wonder whether I am able to apply simulated annealing in to 
> constraint optimization function "constrOptim". Could someone help?
> 
> Thanks very much!
> 
> Sincerely,
> Hui 
> 
>   [[alternative HTML version deleted]]
> 
> __
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 


-

Hans W. Borchers
ABB Corporate Research Germany
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[R] Question about Constraint Optimization

2008-06-26 Thread HNie
Dear All,

I am having trouble in using R function "constrOptim" to do constraint 
optimization. It seems that "constrOptim" calls function "optim" when it 
does the optimization, and "optim" allows us to set "method" to be "SANN" 
if we want to use simulated annealing. In "optim", the function allows us 
to set gradient to be NULL when we treat "method" as "SANN". But in 
"constrOptim", the function does not allow us to set gradient as "SANN" if 
we set "method" to be "SANN". I am just curious about it.

I just wonder whether I am able to apply simulated annealing in to 
constraint optimization function "constrOptim". Could someone help?

Thanks very much!

Sincerely,
Hui 

[[alternative HTML version deleted]]

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.