[FLR-list] FLSR sigma2

[Iago Mosqueira]

Off-topic now, but...

Well, it is a big question still

http://www.newstatesman.com/2013/07/mysteries-bicycle


Iago

On 08/08/2013 03:14 PM, Clara Ulrich wrote:
> Ah ah, yes, that might be the reason! We still haven't found the mystery of these round wheels!
> 
> -----Original Message-----
> From: flr-list-bounces at r-forge.wu-wien.ac.at [mailto:flr-list-bounces at r-forge.wu-wien.ac.at] On Behalf Of Laurie
> Sent: 08 August 2013 14:24
> To: flr-list at r-forge.wu-wien.ac.at
> Subject: Re: [FLR-list] FLSR sigma2
> 
> Probably why for the last two years a Britain has won the Tour De France!
> Laurie
> 
> On 08/08/13 13:59, Clara Ulrich wrote:
>> Ok thanks for quick answer!
>>
>> And I don't know why but I still find it easier to remember how to 
>> bike - probably because bike's design and functioning hasn't changed 
>> that much from when I was a child, much less new fancy features 
>> popping up;-) Clara
>>
>> -----Original Message-----
>> From: flr-list-bounces at r-forge.wu-wien.ac.at 
>> [mailto:flr-list-bounces at r-forge.wu-wien.ac.at] On Behalf Of Iago 
>> MOSQUEIRA (JRC)
>> Sent: 08 August 2013 13:36
>> To: flr-list at r-forge.wu-wien.ac.at
>> Subject: Re: [FLR-list] FLSR sigma2
>>
>> On 08/08/2013 12:19 PM, Clara Ulrich wrote:
>>> Hi all,
>>>
>>> I feel that my FLR brain is smelting away, I just do not use it enough anymore to keep a sharp up-to-date knowledge ;-( And indeed, trying to re-run some 2 years old from R2.8.1 I get some bugs of course.
>>>
>>> Is there nothing like a sigma2 in the FLSR parameters anymore? Is this stored something else?
>>>
>>> Thanks
>>> Clara
>> Hi,
>>
>> But FLRing is like cycling, never to be forgotten...
>>
>> The formulation of the likelihood that has been used for the last 2-3 
>> years does not have sigma2 as an estimated parameter, but is instead 
>> calculated, as it was just a nuisance parameter that made life more 
>> dificult forn the optimizer
>>
>>> getMethod('loglAR1', c('FLQuant', 'FLQuant'))
>>
>> Method Definition:
>>
>> function (obs, hat, ...)
>> {
>>      .local <- function (obs, hat, rho = 0)
>>      {
>>          n <- dim(obs)[2]
>>          rsdl <- (obs[, -1] - rho * obs[, -n] - hat[, -1] + rho *
>>              hat[, -n])
>>          s2 <- sum(rsdl^2, na.rm = T)
>>          s1 <- s2
>>          if (!all(is.na(rsdl[, 1])))
>>              s1 <- s1 + (1 - rho^2) * (obs[, 1] - hat[, 1])^2
>>          sigma2 <- sigma(obs, hat)^2
>>          n <- length(obs[!is.na(obs)])
>>          sigma2.a <- (1 - rho^2) * sigma2
>>          res <- (log(1/(2 * pi)) - n * log(sigma2.a) + log(1 -
>>              rho^2) - s1/(2 * sigma2.a))/2
>>          if (!is.finite(res))
>>              res <- -1e+100
>>          return(res)
>>      }
>>      .local(obs, hat, ...)
>> }
>> <environment: namespace:FLCore>
>>
>> which class sigma()
>>
>>> getMethod('sigma', c('FLArray'))
>> Method Definition:
>>
>> function (object, ...)
>> {
>>      .local <- function (object, hat = rep(0, length(object)))
>>      {
>>          if (all(is.na(hat)))
>>              return(Inf)
>>          SS <- sum((object - hat)^2, na.rm = TRUE)
>>          return((SS/length(hat[!is.na(hat)]))^0.5)
>>      }
>>      .local(object, ...)
>> }
>> <environment: namespace:FLCore>
>>
>> Signatures:
>>          object
>> target  "FLArray"
>> defined "FLArray"
>>
>> which calculates it from SS.
>>
>>
>> Iago
>>
>>
>>
>> --
>> Dr Iago Mosqueira
>>
>> European Commission - Joint Research Center Institute for the 
>> Protection and Security of the Citizen (IPSC) Maritime Affairs Unit 
>> FISHREG - Scientific Support to Fisheries TP 051, Via Enrico Fermi 
>> 2749
>> I-21027 Ispra (VA), Italy
>>
>> Office : +39 0332 785413
>> Fax: +39 0332 789658
>>
>> iago.mosqueira at jrc.ec.europa.eu
>>
>> http://fishreg.jrc.ec.europa.eu/home
>>
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