similar to: a quick Q about memory limit in R

Displaying 20 results from an estimated 2000 matches similar to: "a quick Q about memory limit in R"

2012 Apr 05
4
Appropriate method for sharing data across functions
In trying to streamline various optimization functions, I would like to have a scratch pad of working data that is shared across a number of functions. These can be called from different levels within some wrapper functions for maximum likelihood and other such computations. I'm sure there are other applications that could benefit from this. Below are two approaches. One uses the <<-
2003 Jul 18
3
question about formulating a nls optimization
Dear list, I'm migrating a project from Matlab to R, and I'm facing a relatively complicated problem for nls. My objective function is below: >> objFun <- function(yEx,xEx,tEx,gamma,theta,kappa){ yTh <- pdfDY(xEx,tEx,gamma,theta,kappa) sum(log(yEx/yTh)^2) } The equation is yTh=P(xEx,tEx) + noise. I collect my data in: >> data <-
2012 Oct 09
1
how to convert by lists in data.frames
Dear R-helpers, I’ve got a summary of results from a by() call that I am making with a list of more than two of factors not very different from the example in the by() help page require(stats) by(warpbreaks[, 1], warpbreaks[, -1], summary) The result of the command gives a list of the form wool: A tension: L Min. 1st Qu. Median Mean 3rd Qu. Max. 25.00 26.00
2002 Apr 03
3
non-stationary covariance
Hi ! Sorry for my ignorance. I have two questions: 1) which is in R the function to make a covariogram of spatial data ? 2) does anyone know if there exist the possibility in R of performing kriging with an arbitrary covariance function ? If I have well understood the Krig procedure offers only three possibilities (expcov, gauscov and sphercov) that are the common models for stationary and
2008 Aug 20
3
bug in lme4?
Dear all, I found a problem with 'lme4'. Basically, once you load the package 'aod' (Analysis of Overdispersed Data), the functions 'lmer' and 'glmer' don't work anymore: library(lme4) (fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy)) (gm1 <- glmer(cbind(incidence, size - incidence) ~ period + (1 | herd), family = binomial, data
2004 Oct 31
2
Obtaining fitted model information
Dear list, I am brand new to R and using Dalgaard's (2002) book Introductory Statistics with R (thus, some of my terminology may be incorrect). I am fitting regression models and I want to use Hurvich and Tsai's AICC statistic to examine my regression models. This penalty can be expressed as: 2*npar * (n/(n-npar-1)). While you can obtain AIC, BIC, and logLik, I want to impose the AICC
2003 May 22
1
(no subject)
Dear R-helpers! What it's means "Rank failure in Choleski decomposition" by using of function surf.gls {spatial}? Sincerely Yours Branimir K. Hackenberger
2010 Sep 15
1
optim with BFGS--what may lead to this, a strange thing happened
Dear R Users on a self-written function for calculating maximum likelihood probability (plz check function code at the bottom of this message), one value, wden, suddenly jump to zero. detail info as following: w[11]=2.14 lnw =2.37 2.90 3.76 ... regw =1.96 1.77 1.82 .... wden=0.182 0.178 0.179... w[11]=2.14 lnw=2.37 2.90 3.76 ... regw =1.96 1.77 1.82 .... wden=0.182
2008 Mar 27
1
A faster way to compute finite-difference gradient of a scalar function of a large number of variables
Hi All, I would like to compute the simple finite-difference approximation to the gradient of a scalar function of a large number of variables (on the order of 1000). Although a one-time computation using the following function grad() is fast and simple enough, the overhead for repeated evaluation of gradient in iterative schemes is quite significant. I was wondering whether there are
2010 Sep 07
5
question on "optim"
Hey, R users I do not know how to describe my question. I am a new user for R and write the following?code for a dynamic labor economics?model and use OPTIM to get optimizations and parameter values. the following code does not work due to the?equation: ?? wden[,i]<-dnorm((1-regw[,i])/w[5])/w[5] where w[5]?is one of the parameters (together with vector a, b and other elements in vector
2007 Sep 07
1
negative value for AIC and BIC
Hi all, I obtained negative values for AIC and BIC criteria for a particular model that I have developped... I don't remember to have negative values for these crietria for others applications, so I am a little suprised... Could anyone tell me if something is wrong or his conclusion concerning my model? Best regards, Olivier.
2003 Nov 21
1
: BIC for gls models
Hi all, I would like to know how the BIC criterion is calculated for models estimated using gls( ) function. I read in Pinheiro & Bates (2000) p84 that BIC = -2logL + npar*log(N) (for the ML method), or BIC = -2logLR + npar*log(N-p) (for the REML method) but when I use any of these formulae I don't obtain the result given by R. Thanks in advance for any help. Eve CORDA Office national
2010 Nov 15
1
comparing levels of aggregation with negative binomial models
Dear R community, I would like to compare the degree of aggregation (or dispersion) of bacteria isolated from plant material. My data are discrete counts from leaf washes. While I do have xy coordinates for each plant, it is aggregation in the sense of the concentration of bacteria in high density patches that I am interested in. My attempt to analyze this was to fit negative binomial
2017 Apr 25
4
R-3.4.0 and recommended packages
Am Dienstag, 25. April 2017, 08:50:34 schrieb Dirk Eddelbuettel: > On 25 April 2017 at 14:58, G?ran Brostr?m wrote: > | hello, > | > | I just installed R-3.4.0 from scratch: > | > | $ sudo apt install r-base > | > | but when I try > | > | > library(survival, lib.loc = "/usr/lib/R/library") > | > fit <- coxph(Surv(exit, event) ~ x, data =
2018 Apr 17
1
Minor glitch in optim()
Having worked with optim() and related programs for years, it surprised me that I haven't noticed this before, but optim() is inconsistent in how it deals with bounds constraints specified at infinity. Here's an example: # optim-glitch-Ex.R x0<-c(1,2,3,4) fnt <- function(x, fscale=10){ yy <- length(x):1 val <- sum((yy*x)^2)*fscale } grt <- function(x, fscale=10){ nn
2008 Nov 29
1
Subset by string name?
Hi all, I thought this should be very simple, but I'm not sure where the problem is. I have a .txt data file that contains X and Y coordinates of trees and their family names: "X" "Y" "Mark" 0 28 "Sapotaceae" 1 30 "Meliaceae" 1 40 "Meliaceae" 1 60 "Mimosaceae" 1 76 "Olacaceae" 1.5 73 "Myristicaceae" 2
2004 Jul 16
1
Does AIC() applied to a nls() object use the correct number of estimated parameters?
I'm wondering whether AIC scores extracted from nls() objects using AIC() are based on the correct number of estimated parameters. Using the example under nls() documentation: > data( DNase ) > DNase1 <- DNase[ DNase$Run == 1, ] > ## using a selfStart model > fm1DNase1 <- nls( density ~ SSlogis( log(conc), Asym, xmid, scal ), DNase1 ) Using AIC() function: >
2012 Mar 18
1
Converting expression to a function
Previously, I've posted queries about this, and thanks to postings and messages in response have recently had some success, to the extent that there is now a package called nlmrt on the R-forge project https://r-forge.r-project.org/R/?group_id=395 for solving nonlinear least squares problems that include small or zero residual problems via a Marquardt method using a call that mirrors the nls()
2009 Oct 25
1
Datasets for "The Statistical Sleuth"
Hi everyone, I wonder if there already exists any R packages containing all the data sets for the book "The Statistical Sleuth" (http://www.proaxis.com/~panorama/home.htm; also available at StatLib http://lib.stat.cmu.edu/datasets/sleuth). I'm writing an R package with a friend for one of our stat courses where SAS is the main tool being used. As the time is limited and half of the
2006 Nov 01
1
How to find further informations on specific options?
Dear friends, When i read the R-help , i often find the following case: e.g.:surf.gls(np, covmod, x, y, z, nx = 1000, ...) #Package Spatial: Arguments: covmod: function to evaluate covariance or correlation function * ...: parameters for 'covmod'* How should i find the further information on "*...: parameters for 'covmod'*" ? I use the ?covmod, but