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Hi, I'm having a problem converting a Matlab program into R. The R code works almost all the time, but about 4% of the time R's optim function gets stuck on a local minimum whereas matlab's fminsearch function does not (or at least fminsearch finds a better minimum than optim). My understanding is that both functions default to Nelder-Mead optimization, but what's different about

Dear R-users, I am trying to port to R something that I wrote in Matlab to perform model parameter optimization using the Nelder-Mead simplex method (fminsearch). I read the help on ?optim (which seems to be the way to go) as well as a bunch of posts on the topic, but I would like to make sure about something before I spend to much time trying to reproduce something that is not possible. The

Hi there, I have a piece of Matlab code I use to optimise a trding strategy. If there are any Matlab/R specialists out there, I would appreciate your help in doing the exact same optimisation in R. I suspect I would use nlm() in R but am not sure where to define my constraints. I have attached my Matlab code below for reference. Many thanks. Constraints function [c,ceq]=TriskellConstraints(X)

is there a good notes for loops(if else and while) in r. I have a code written in Matlab and I tried to rewrite it in R but it does not give me the write result . for example in matlab the result is (1 2 3 4) In r it is give my only 2 One more question if I have variable,lets say x and I use it in a loop and I update x each time in the loop . How can I get a vector for all X's. Thank you

hi, I have question. I worte r function that suppsoe ti return x and y to me. when I use that function in the middle of a code ( i use source) it give me the value of x,y but when i write x,ro y it says (not found). so my question is that I want when i load this function to return the varibles x and y beuse the rest of my code depends on thse variables. Thank you HI

*Hi all, I''m not quiet sure the most reasonable way to dealing with bonding on xenserver. My configuration is as follow. It was ok if i do nothing, but When I tried to ''service network restart'', the bond is break. Then, /proc/net/bonding/pbond: Slave Interface: eth0 eth1 was down bonding MII status: down My questions are: how to deal with this situation? how to avoid

Hi! I've just begun writing a program that searches for the minimum of a function with golden section search. In order to do this in a nice way I need a function that takes a function name and an argument and returns the function value for that argument, i .e just like Matlab's 'feval'. Is there any? Thanks before hand! Best regards, Fredrik Thuring, Codan Insurance A/S

Hi everyone, i?m a new user of R and i?m trying to translate an linear optimization problem from Matlab into r. The matlab code is as follow: options = optimset('Diagnostics','on'); [x fval exitflag] = linprog(f,A,b,Aeq,beq,lb,ub,[],options); exitflag fval x=round(x); Where: f = Linear objective function vector (vector of 45,rows) A = Matrix for linear inequality

As the issue concerns both the -user (configuration) and -devel (OOPS), I''m sending this message to both lists. Some time ago I complained about two problems: - VLANs are not working on machines with 100 Mbit cards - I get a kernel Oops (sometimes panic) when I try to use bonding and VLANs with Xen The root of the issue is the same in both cases: VLAN interfaces must *not* be

As the issue concerns both the -user (configuration) and -devel (OOPS), I''m sending this message to both lists. Some time ago I complained about two problems: - VLANs are not working on machines with 100 Mbit cards - I get a kernel Oops (sometimes panic) when I try to use bonding and VLANs with Xen The root of the issue is the same in both cases: VLAN interfaces must *not* be

Deal all: i want to do the probit with sample selection estimation, the following is my code: probit with sample selection can be done by stata :heckprob The heckprobll is the likelihood function shown in W.H. Greene 5th p714 ¡´ The question is the convergence is very slow compare with Stata using likellihood only. ¡´ Second i did the similar way in matlab using fminsearch , the estimated

Dear R users, I am pleased to announce the release of three new R packages: optimbase, optimsimplex, and neldermead. - optimbase provides a set of commands to manage an abstract optimization method. The goal is to provide a building block for a large class of specialized optimization methods. This package manages: the number of variables, the minimum and maximum bounds, the number of non linear

Dear R users, I am pleased to announce the release of three new R packages: optimbase, optimsimplex, and neldermead. - optimbase provides a set of commands to manage an abstract optimization method. The goal is to provide a building block for a large class of specialized optimization methods. This package manages: the number of variables, the minimum and maximum bounds, the number of non linear

Hello, I have a problem finding a root of a function, which I define like this: tuki <- function(u, x, a, lambda){ if((lambda%%1>0) & u<0) {u<-(u+0i)} f <- Re(x-(a*(u)^lambda-(1-(u))^lambda)/lambda) f } What I want to do is to find the root, but without specifying the interval within which to search for it. I can do it easily in MATLAB with fsolve() or fzero() functions. I

Hi, I have written an R translation of C.T. Kelley's Matlab version of the Nelder-Mead algorithm. This algorithm is discussed in detail in his book "Iterative methods for optimization" (SIAM 1999, Chapter 8). I have tested this relatively extensively on a number of smooth and non-smooth problems. It performs well, in general, and it almost always outperforms optim's