similar to: Fitting Weibull Model with Levenberg-Marquardt regression method

Hi everybody, I'm trying to create a script that picks a txt file with 2 columns of coordinates (depth and variable1) and automatically tries to fit several polynomial with the function nls(). After that, it creates a list of observed, predict, residuals and other, and then it calculates AIC, RMSD, MAD and R^2. At the end of the script I create a series of vectors with MAD for all

Hi, I have a problem with R CMD BATCH, because I created a .bat file to run a script: C:\R\R-2.9.2\bin\R CMD BATCH C:\Scrip_test.R It work perfectly but after 3 lines of script there is a line with a nls() function that cannot be fitted and this end in an error message. I'm not bother by the error message, I just want that the script continue. If I use the R windows GUI the script show the

Hi, It seems to me that the most suitable method in R for curve-fitting is the use of nls, which uses a Gauss-Newton (GN) algorithm, while the use of the Levenberg-Marquardt (LM) algorithm does not seem to be very stressed in R. According to this [1] by Ripley, 'Levenberg-Marquardt is hardly competitive these days' which could imply the low emphasize on LM in R. The position of LM is, to

Hi All, Is the Levenberg-Marquardt algorithm available in R. This method combines the steepest descent algorithm and Newton's method. Thanks in Advance, Dermot MacSweeney. ************************************************************** Dermot MacSweeney NMRC, Email: dsweeney at nmrc.ucc.ie Lee Maltings, Tel: +353 21 904178 Prospect Row, Fax: +353 21 270271 Cork, WWW:

Hello, i have a problem with the function nls(). This are my data in "k": V1 V2 [1,] 0 0.367 [2,] 85 0.296 [3,] 122 0.260 [4,] 192 0.244 [5,] 275 0.175 [6,] 421 0.140 [7,] 603 0.093 [8,] 831 0.068 [9,] 1140 0.043 With the nls()-function i want to fit following formula whereas a,b, and c are variables: y~1/(a*x^2+b*x+c) With the standardalgorithm

Hello, I want to fit some non linear models with the Levenberg-Marquardt algorithm. It doesn''t seem to exist any function to do this in R ( well, maybe one does, but I''m a new user, and the only documentation I have is "An introduction to R"). I''d like to know if this function exists, maybe throught an additionnal package. I''d also like to know if if

Dear all, I would like to use the Levenberg-Marquardt algorithm for non-linear least-squares regression using function nls.lm. Can anybody help me to find a a way to compute confidence intervals on the fitted parameters as it is possible for nls (using confint.nls, which does not work for nls.lm)? Thank you for your help Michael

Hi guys, I have a data-set that fits well into a Weibull model y = a-b*exp(-c*x^d). I want to estimate the parameters of the coefficients a, b, c and d, given x and y. Can you guys help me? Just as an example, I fit the data y <- c(1,2,3,4,10,20) and x <- c(1,7,14,25,29,30) According to this model above, and using the software CurveExpert, and I got the estimates of a (2.95),b (2.90),c

We operate a samba('18p10) server accessed by WIN3.11, 9x & NT4 clients, security=share. Uptil now, the NT clients have been pre service pack 3 & therefore sent cleartext passwords. Post-SP3 we need to enable encrypted passwords for the NT clients whilst preserving cleartext for the rest. For various (political) reasons, we cant' get the clients to use the registry hack to

Hi, I am now running Samba services to a network of 200 or so PC's accessing a central UNIX filserver and overall it is a success. There are just a few niggles however. I'll email my smb.conf later if this is required but I guess this may be a common newbie problem. Users all have a home directory mapped to their Z drive. This is okay, but if they try to rename a file (right click

> Date: Fri, 14 Aug 1998 09:25:41 +0100 (British Summer Time) > From: Anthony Farrow <a.n.farrow@cranfield.ac.uk> > To: samba@samba.anu.edu.au > Subject: Files not copying across Samba > Message-ID: <SIMEON.9808140941.C@ccanf2.cranfield.ac.uk> > > > > I am having a problem with a single user on our Samba system. We are > running Samba on a DEC UNIX

Hello, I would like to start running a script from Python with the Rscript command. I tested several ways of invoking R from Python and I finally I succeeded. The problem is that the script starts but R does not recognize the installed packages. I tried simplifying the matter and I created a script.bat with the classic commands: Rscript c:\test.R If I run it by double clicking on it it works

In efforts to improve optimization tools for R, one of my interests has been getting automatic differentiation capabilities so that analytic rather than numerical derivatives can be used. They would be helpful in several other areas besides optimization, My timings show factors of the order of 1000s in time improvements by avoiding numerical derivatives in some cases. There has been some work in

Hi! I'm translating some code from Matlab to R and I found a problem. I need to translate Matlab's function 'lsqnonlin' (http://www-ccs.ucsd.edu/matlab/toolbox/optim/lsqnonlin.html) into R, and at the beginning I thought it would be the same as R's 'optim'. But then I looked at the definition of 'lsqnonlin' and I don't quite see how to make

I appologise as this is probably an FAQ but I have read the FAQ's and have been unsuccessfull in finding a solution. I have a Solaris 2.5 server running the latest version of samba (can't remember the version no. but was only downloaded on Friday). I have set up a homes share and would like to connect my NT workstations to it. I have been able to connect by specifying the username and

In the course of revising a paper I have had occasion to attempt to maximize a rather complicated log likelihood using the function nlm(). This is at the demand of a referee who claims that this will work better than my proposed use of a home- grown implementation of the Levenberg-Marquardt algorithm. I have run into serious hiccups in attempting to apply nlm(). If I provide gradient and

Dear Mr Graves, Thank you very much for your response. Nobody else from this mailing list ventured to reply to me for the two weeks since I posted my question. "nlminb" and "optim" are just optimization procedures. What I need is not just optimization, but a nonlinear CURVE FITTING procedure. If there is some way to perform nonlinear curve fitting with the

Hello! I am running R-2.3.1-i386-1 on Slackware Linux 10.2. I am a former matlab user, moving to R. In matlab, via the cftool, I performed nonlinear curve fitting using the method "nonlinear least squares" with the "Trust-Region" algorithm and not using robust fitting. Is it possible to perform the same analysis in R? I read quite a lot of R documentation, but I could not find

Dear All, In the past I have often used minpack (http://bit.ly/zXVls3) relying on the Levenberg-Marquardt algorithm to perform non-linear fittings. However, I have always dealt with a function of a single variable. Is there any difference if the function depends on two variables? To fix the ideas, please consider the function f(R,N)=(a/(log(2*N))+b)*R+c*N^d, where a,b,c,d are fit parameters. For

The package minpack.lm allows nonlinear regression problems to be addressed with a modification of the Levenberg-Marquardt algorithm based on the implementation of 'lmder' and 'lmdif' in MINPACK. Version 1.0-8 of the package is now available on CRAN. Changes in version 1.0-8 include: o possibility to obtain standard error estimates on the parameters via new methods for