similar to: any more direct-search optimization method in R

Displaying 20 results from an estimated 4000 matches similar to: "any more direct-search optimization method in R"

2005 May 22
3
constraints
Is there a package in R that handles general linear (in-)equality + box constrained optimization? If it is not there, could anyone advise me which way to go? And/or point me to packages that solve these problems partially? best, ingmar -- Ingmar Visser Department of Psychology, University of Amsterdam Roetersstraat 15, 1018 WB Amsterdam The Netherlands http://users.fmg.uva.nl/ivisser/ tel:
2007 Sep 07
1
'initial value not feasible' in constrOptim
Dear friends. I am using function constrOptim(c(0.5,0.3,0.5), fit.error, fit.error.grr, ui=-1*ui,ci=-1*ci) and I am confronted with error message "initial value not feasible" I plug in the initial value of (0.5,0.3,0.5) to function fit.error and fit.error.grr and have pretty reasonable result. I inequality "ui %*% theta - ci >= 0" as suggested in the R manual and it is
2005 Mar 23
4
non-derivative based optimization and standard errors.
Hi AlL, I ahve this problem that my objective function is discontinous in the paramaters and I need to use methods such as nelder-mead to get around this. My question is: How do i compute standard errors to a problem that does not have a gradient? Any literature on this is greatly appreciated. Jean,
2004 Aug 09
4
linear constraint optim with bounds/reparametrization
Hello All, I would like to optimize a (log-)likelihood function subject to a number of linear constraints between parameters. These constraints are equality constraints of the form A%*%theta=c, ie (1,1) %*% 0.8,0.2)^t = 1 meaning that these parameters should sum to one. Moreover, there are bounds on the individual parameters, in most cases that I am considering parameters are bound between zero
2005 Mar 22
5
Convert timeseries to transition matrix
Hi All, Does someone have an idea of how to cleverly convert a categorical timeseries into a transition matrix? Ie, I have something like: x<- c(1,1,2,1,1,2,2,2,1,2), And I want a matrix with counts and/or probabilities: > tr <- matrix(c(2,3,2,2),2,2) > tr [,1] [,2] [1,] 2 2 [2,] 3 2 Meaning that there are two transitions from 1 to 1, two from 1 to 2, three from 2 to 1
2006 Oct 13
3
Barplot legend position
Dear useRs, I'm trying to create a barplot like so: x=matrix(1:10,2,5) barplot(x,leg=c("left","right"),besid=T) The legend is placed in default position topright, however the data are plotted there too. I tried controlling the legend position by adding x="topleft" but this results in an error that x matches multiple formal arguments. Leaving out the legend
2009 Jun 03
1
Using constrOptim() function
I have a function myFunction(beta,x) where beta is a vector of coefficients and x is a data frame (think of it as a matrix). I want to optimize the function myFunction() by ONLY changing beta, i.e. x stays constant, with 4 constraints. I have the following code (with a separate source file for the function): rm(list=ls()) source('mySourceFile')
2008 Jan 18
1
constrOptim with method SANN
Hi Everyone, I'm trying to minimize a function using constrOptim with the simulated annealing method SANN. If I understand constrOptim well, it basically passes most of its arguments to optim while somehow enforcing the constraints. My problem is, that since SANN does not need gradients, when using optim with SANN, the gr argument of optim is used to specify a function to create the next
2004 May 12
4
bus error macosx/off-topic
Hi All, I'm building a package using C/C++ and Fortran code which usually runs fine. However I do get occasional bus errors around the time of exiting one of the C functions. Where do I need to be looking to solve this problem? Do bus errors stem from unmapped memory exceptions? How can I find out if that is what is happening while running R? Any hints greatly appreciated. Best, ingmar
2005 Apr 12
3
where is internal function of sample()?
Hi there, I am trying to write a c++ shared library for R. I need a function which has the same functionality as sample() in R, i.e., does permutation, sample with/without replacement. Does R have internal sample routine so that I can call it directly? I did not find it in R.h, Rinternal.h. Thanks
2008 Jun 26
1
Question about Constraint Optimization
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
2011 Feb 11
2
fitdistr question
Hello, I tried to fit a poisson distribution but looking at the function fitdistr() it does not optimize lambda but simply estimates the mean of the data and returns it as lambda. I'm a bit confused because I was expecting an optimization of this parameter to gain a good fit... If I would use mle() of stats4 package or mle2() of bbmle package, I would have to write the function by myself
2004 Mar 30
1
Console/command line output
Hi all, I am working on Macos x 10.3 (Panther) to build a package consisting of C/C++ code that is called from R. In the C/C++-sources I use several commands to print info to the console: std::cout << "info" << endl; and: Rprintf("info\n"); Both work fine when R is run on the command line but neither works when running Raqau (I did check the preference boxes
2008 Apr 07
2
tcltk issue remains
Dear R-help, I'm trying to load the fGarch package and keep running into problems with tcltk: After succesfully instaling fGarch (and dependencies) I get: >library(fGarch) Loading required package: fBasics Loading required package: fImport Loading required package: fSeries Loading required package: robustbase Loading required package: fCalendar Loading required package: MASS Loading
2009 Sep 11
1
constrOptim parameters
Dear R wizards: I am playing (and struggling) with the example in the constrOptim function. simple example. let's say I want to constrain my variables to be within -1 and 1. I believe I want a whole lot of constraints where ci is -1 and ui is either -1 or 1. That is, I have 2*N constraints. Should the following work? N=10 x= rep(1:N) ci= rep(-1, 2*N) ui= c(rep(1, N), rep(-1, N))
2009 Mar 12
2
Time-Ordered Clustering
Hello All, Does anyone know of a package that performs constraint-based clusters? Ideally the package could perform "Time-Ordered Clustering", a technique applied in a recent journal article by Runger, Nelson, Harnish (using MS Excel). Quote, "in our specific implementation of constrained clustering, the clustering algorithm remains agglomerative and hierarchical, but observations
2008 Mar 05
6
box-constrained
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2008 May 12
1
hessian in constrained optimization (constrOptim)
Dear helpers, I am using the function "constrOptim" to estimate a model with ML with an inequality constraint using the option method='Nelder-Mead'. When I specify the option: hessian = TRUE I obtain the response: Error in f(theta, ...) : unused argument(s) (hessian = TRUE) I guess the function "constrOptim" does not allow this argument which, on the other hand, is
2009 Jul 02
2
constrained optimisation in R.
i want to estimate parameters with maximum likelihood method with contraints (contant numbers). for example sum(Ai)=0 and sum(Bi)=0 i have done it without the constraints but i realised that i have to use the contraints. Without constraints(just a part-not complete): skellamreg_LL=function(parameters,z,design) { n=length(z); mu=parameters[1]; H=parameters[2]; Apar=parameters[3:10];
2012 Feb 22
4
Week number from a date
Hi My data looks like this startDate="2008-06-01" dateRange =c( "2008-10-01","2008-12-01") Is there any method to find the week number from the startDate range ----- Thanks in Advance Arun -- View this message in context: http://r.789695.n4.nabble.com/Week-number-from-a-date-tp4410223p4410223.html Sent from the R help mailing list archive at Nabble.com.