[R] NLM OUTPUT

[Peter Ehlers]

Bob,

I very strongly suggest that you do two things:

1. look at help("str"); then get in the habit of using
    the str() function frequently.

2. peruse "An Introduction to R, especially Chapter 6
    which would have solved your problem.

Regards,
  -Peter Ehlers

robertagnew at discover.com wrote:
> Thanks, Steve.  I believe that's all I needed.  I couldn't find that 
> r$estimate syntax anywhere in the manual.  I'm new to R, having used SAS 
> exclusively in the past.  I was able to run the optimizing functions nlm 
> and optim successfully, but I couldn't figure out how to access the 
> estimates.  I tried another function constroptim rather unsuccessfully; it 
> ran but did very little so I took a different approach.
> 
> Bob
> 
> Robert Agnew | Discover
> Director Acquisition Analytics
> Marketing – Analysis & Pricing
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> 
> 
> 
> Steve Lianoglou <mailinglist.honeypot at gmail.com> 
> 11/05/2009 04:56 PM
> 
> To
> "<robertagnew at discover.com>" <robertagnew at discover.com>
> cc
> r-help at r-project.org
> Subject
> Re: [R] NLM OUTPUT
> 
> 
> 
> 
> 
> 
> Hi Bob,
> 
> On Nov 5, 2009, at 3:04 PM, <robertagnew at discover.com> 
> <robertagnew at discover.com 
>  > wrote:
> 
>> I am missing something fundamental.  I ran the function nlm, but I 
>> don't
>> understand how to extract the optimal solution as a numeric vector. 
>> The
>> function produces it as one element of a list.  I don't see anything 
>> in
>> the R documentation about converting such a list element to the 
>> vector it
>> displays.
> 
> Are you just asking how to pull out the appropriate parts of the 
> returned value from the nlm function call?
> 
> Taking code from the Example section of ?nlm, run this:
> 
> R> f <- function(x, a) sum((x-a)^2)
> R> r <- nlm(f, c(10,10), a=c(3,5))
> 
> Now look at "r"
> R> r
> $minimum
> [1] 3.371781e-25
> 
> $estimate
> [1] 3 5
> 
> $gradient
> [1]  6.750156e-13 -9.450218e-13
> 
> $code
> [1] 1
> 
> $iterations
> [1] 2
> 
> To get the minimum, or estimate you just access it like:
> R> r$minimum
> [1] 3.371781e-25
> 
> R> r$estimate
> [1] 3 5
> 
> Is this what you're asking?
> 
> -steve
> 
> ps:
> r[['minimum']] and r[['estimate']] would also work, as would r[[1]] 
> and r[[2]]
> 
> --
> Steve Lianoglou
> Graduate Student: Computational Systems Biology
>    |  Memorial Sloan-Kettering Cancer Center
>    |  Weill Medical College of Cornell University
> Contact Info: http://cbio.mskcc.org/~lianos/contact
> 
> 
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