similar to: "optim" and "nlminb"

Displaying 20 results from an estimated 1000 matches similar to: ""optim" and "nlminb""

2012 Apr 28
2
"Modified Diebold-Mariano Test" with forecast package
Hi I tried to calculate modified Diebold-Mariano Test in R . I have already find a "forecast" package to calculate the Diebold-Mariano Test. Please let me know how to obtain " Modified Diebold-Mariano Test" ? Regards, Serdar -- View this message in context: http://r.789695.n4.nabble.com/Modified-Diebold-Mariano-Test-with-forecast-package-tp4594648p4594648.html Sent from
2004 Aug 03
1
nlminb vs optim
Dear R-help group, I have to maximize a likelihood with 40 parameters and I want to compare the MLE given by "nlminb" (Splus2000, on Windows) with those given by "optim" (R, on Unix). 1) On Splus, The algorithm "nlminb" seems to converge (the parameters stabilize) , it stops after several iterations ( around 400) with the message :"FUNCTION EVALUATION LIMIT
2005 Mar 14
2
How NuFone.Net's customer service works.
Hello All, I have been using asterisk for some time, and I would like for all to take a look at what NuFone does when they get something called out about their website. I ordered a 800 number from them on 3/4/05, they did not make me aware of the time that they took in provisioning and how terrible their support was. I called them on Tuesday 3/8/05 asked for a phone call because the
2007 Oct 18
1
new FLAC support
as devices that support FLAC come out from time to time, I update the front page on the FLAC site, but it occurred to me that people might miss some of these. the ideal way would be to set up an rss news feed but until that's ready, here are a few from the last month or so: Linn Klimax DS networked digital music player http://www.linn.co.uk/klimax_ds Pioneer SC-LX90 amplifier
2012 Jul 04
2
About nlminb function
Hello I want to use the nlminb function but I have the objective function like characters. I can summarize the problem using the first example in the nlminb documentation. x <- rnbinom(100, mu = 10, size = 10) hdev <- function(par) -sum(dnbinom(x, mu = par[1], size = par[2], log = TRUE)) nlminb(c(9, 12), objective=hdev) With the last instructions we obtain appropriate results. If I have
2009 May 03
3
Optim function in the loop
Hi all, I wrote the following lines of codes try to do some iterations to find the global optimal values, but the function does not execute properly. Every time codes stop after one iteration right after executing the optim() function. Does anyone could have me to take a look? Thanks. if (count>0){ k=k+0.05; mu0=c(83+k,0,0) Sigma0= diag(0.4,3) initpar=c(.1+10*k,10*k,10*k,10*k) # initial
2012 Nov 04
1
Struggeling with nlminb...
Hallo together, I am trying to estimate parameters by means of QMLE using the nlminb optimizer for a tree-structured GARCH model. I face two problems. First, the optimizer returns error[8] false convergence if I estimate the functions below. I have estimated the model at first with nlm without any problems, but then I needed to add some constraints so i choose nlminb.
2008 Dec 03
1
nlminb: names of parameter vector not passed to objective function
Dear R developers, I tried to use nlminb instead of optim for a current problem (fitting parameters of a differential equation model). The PORT algorithm converged much better than any of optim's methods and the identified parameters are plausible. However, it took me a while before spotting the reason of a technical problem that nlminb, in contrast to optim, does not pass names of the
2008 Jul 25
0
nlminb--lower bound for parameters are dependent on each others
Hello I'm trying to solve two sets of equations (each set has four equations and all of them share common parameters) with nlminb procedure. I minimize one set and use their parameters as initial values of other set, repeating this until their parameters become very close to each other. I have several parameters (say,param1, param2) and their constraints are given as inequality and depend
2005 Mar 04
2
Bluetooth phone as SIP handset?
Even better you can set your firefly softphone to auto answer so that you don't even need to be near the pc to answer. Cheers, Dean -----Original Message----- From: asterisk-users-bounces@lists.digium.com [mailto:asterisk-users-bounces@lists.digium.com] On Behalf Of Linn Boyd Sent: Friday, March 04, 2005 2:12 PM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: Re:
2019 Feb 01
0
nlminb with constraints failing on some platforms
>>>>> Kasper Kristensen via R-devel >>>>> on Mon, 28 Jan 2019 08:56:39 +0000 writes: > I've noticed unstable behavior of nlminb on some Linux > systems. The problem can be reproduced by compiling > R-3.5.2 using gcc-8.2 and running the following snippet: > f <- function(x) sum( log(diff(x)^2+.01) + (x[1]-1)^2 ) > opt
2012 Sep 26
2
non-differentiable evaluation points in nlminb(), follow-up of PR#15052
This is a follow-up question for PR#15052 <http://bugs.r-project.org/bugzilla3/show_bug.cgi?id=15052> There is another thing I would like to discuss wrt how nlminb() should proceed with NAs. The question is: What would be a successful way to deal with an evaluation point of the objective function where the gradient and the hessian are not well defined? If the gradient and the hessian both
2010 Dec 07
1
Using nlminb for maximum likelihood estimation
I'm trying to estimate the parameters for GARCH(1,1) process. Here's my code: loglikelihood <-function(theta) { h=((r[1]-theta[1])^2) p=0 for (t in 2:length(r)) { h=c(h,theta[2]+theta[3]*((r[t-1]-theta[1])^2)+theta[4]*h[t-1]) p=c(p,dnorm(r[t],theta[1],sqrt(h[t]),log=TRUE)) } -sum(p) } Then I use nlminb to minimize the function loglikelihood: nlminb(
2010 Mar 24
1
vcov.nlminb
Hello all, I am trying to get the variance-covariance (VCOV) matrix of the parameter estimates produced from the nlminb minimizing function, using vcov.nlminb, but it seems to have been expunged from the MASS library. The hessian from nlminb is also producing NaNs, although the estimates seems to be right, so I can't VCOV that way either. I also tried using the vcov function after minimizing
2019 Jan 31
0
nlminb with constraints failing on some platforms
This is not about the failure on some platforms, which is an important issue. However, what is below may provide a temporary workaround until the source of the problem is uncovered. FWIW, the problem seems fairly straightforward for most optimizers at my disposal in the R-forge (developmental) version of the optimx package at https://r-forge.r-project.org/projects/optimizer/ I used the code ##
2019 Feb 01
0
nlminb with constraints failing on some platforms
No error on Windows 10, R.3.5.2 patched, Rblas compiled with OpenBLAS 0.20, Rlapack is base. > f <- function(x) sum( log(diff(x)^2+.01) + (x[1]-1)^2 ) > opt <- nlminb(rep(0, 10), f, lower=-1, upper=3) > str(opt) List of 6 $ par : num [1:10] 1 1 1 1 1 ... $ objective : num -41.4 $ convergence: int 0 $ iterations : int 66 $ evaluations: Named int [1:2] 96 830 ..-
2011 Apr 13
0
ddply and nlminb
Hello I'm new to R (one week) so please excuse any obvious mistakes in my code or posting. I am attempting to fit a non linear function defining the relationship between dependent variable A and the variables PAR and T grouped by the condition Di. The following steps are taken in the Rcode below: 1) load the data (not shown) 2) define the function to be fit 3) define the starting values
2011 Aug 16
2
Calibrating the risk free interest rate using nlminb
Dear R-users I am trying to find a value for the risk free rate minimizing the difference between a BS call value with impl. volatilities minus the market price of a call (assuming this is just the average bid ask price) Here is my data: http://r.789695.n4.nabble.com/file/n3747509/S%26P_500_calls%2C_jan-jun_2010.csv S%26P_500_calls%2C_jan-jun_2010.csv S0 <- 1136.03 q <- 0.02145608 S0
2011 Jan 21
3
nlminb doesn't converge and produce a warning
Hi Everybody, My problem is that nlminb doesn't converge, in minimising a logLikelihood function, with 31*6 parameters(2 weibull parameters+29 regressors repeated 6 times). I use nlminb like this : res1<-nlminb(vect, V, lower=c(rep(0.01, 12), rep(0.01, 3), rep(-Inf, n-15)), upper=c(rep(Inf, 12), rep(0.99, 3), rep(Inf, n-15)), control = list(maxit=1000) ) and that's the result :
2006 Jul 23
1
How to pass eval.max from lme() to nlminb?
Dear R community, I'm fitting a complex mixed-effects model that requires numerous iterations and function evaluations. I note that nlminb accepts a list of control parameters, including eval.max. Is there a way to change the default eval.max value for nlminb when it is being called from lme? Thanks for any thoughts, Andrew -- Andrew Robinson Department of Mathematics and Statistics