similar to: About simulations

Displaying 20 results from an estimated 2000 matches similar to: "About simulations"

2005 Mar 01
6
Help : delete at random
Hello I would like to delete some values at random in a data frame. Does anyone know how I could do? With best regards Caroline
2006 Oct 11
1
About fitdistr
Dear all, I would like to estimate the parameters of a mixture of two beta binomial distributions. I saw the function fitdistr from the MASS library could be a solution but I have some difficulties. Does anyone know how to specify to fitdistr another function as these which are predefined? Or is there any other solution to estimate the parameters? Thank you in advance Caroline
2007 Apr 27
1
Issues with Sweave and inclusion of graphics from nlme
Dear all, I'm using the nlme package. I would like to introduce the plot of my groupedData object in my latex report using Sweave but it doesn't work. I have no error message in R (Sweave(my.file_Rnw)) and the plot is generated in R, but when I want to see the pdf (I'm using TexnicCenter) of my report, there is an error message and no pdf file is generated. It seems that the plot
2005 Apr 15
1
AR1 in gls function
Dear R-project users I would like to calculate a linear trend versus time taking into account a first order autoregressive process of a single time series (e.g. data$S80 in the following example) using th gls function. gls(S80 ~ tt,data=data,corAR1(value, form, fixed)) My question is what number to set in the position of value within corAR1? Should it be the acf at lag 1? I look forward for
2004 Sep 14
3
repeated measures and covariance structures
Hello- I'm trying to do some repeated measures ANOVAs. In the past, using SAS, I have used the framework outlined in Littell et al.'s "SAS System for Mixed Models", using the REPEATED statement in PROC MIXED to model variation across time within an experimental unit. SAS allows you to specify different within-unit covariance structures (e.g., compound symmetric, AR(1), etc.) to
2008 Mar 08
1
analysing mixed effects/poisson/correlated data
I am attempting to model data with the following variables: timepoint - n=48, monthly over 4 years hospital - n=3 opsn1 - no of outcomes total.patients skillmixpc - skill mix percentage nurse.hours.per.day Aims To determine if skillmix affects rate (i.e. no.of.outcomes/total.patients). To determine if nurse.hours.per.day affects rate. To determine if rates vary between
2018 Jun 07
3
FTS Solr errors using doveadm
Solr 7 returns JSON by default but fts_solr requires XML. Would be good to have wt=xml added to the query to force it to xml all the time, this would prevent errors if solr has not had xml set as default for index. Dovecot 2.2.36 Centos 6 *Doveadm Request:* doveadm search -u caroline at covermg.com TEXT smith doveadm(caroline at covermg.com): Error: fts_solr: Invalid XML input at 1:0: not
2009 May 28
3
String replacement in an expression
Dear R-experts, I need to replace in an expression the character "Cl" by "Cl+beta" But in the following case: form<-expression((Cl-(V *ka) ) +(V *Vm *exp(-(Clm/Vm) *t))) gsub("Cl","(Cl+beta)",as.character(form)) We obtain: [1] "((Cl+beta) - (V * ka)) + (V * Vm * exp(-((Cl+beta)m/Vm) * t))" the character "Clm" has been
2018 Apr 18
0
mgcv::gamm error when combining random smooths and correlation/autoregressive term
I am having difficulty fitting a mgcv::gamm model that includes both a random smooth term (i.e. 'fs' smooth) and autoregressive errors. Standard smooth terms with a factor interaction using the 'by=' option work fine. Both on my actual data and a toy example (below) I am getting the same error so am inclined to wonder if this is either a bug or a model that gamm is simply unable
2008 Jan 25
1
Trouble setting up correlation structure in lme
Hi, I'm trying to set up AR(1) as a correlation structure in modeling some data (attached file data.txt in text format) with lme, but have trouble getting it to work. Incent, Correctness, and Oppor are 3 categorical variables, Beta is a response variable, and Time is an equally-spaced variable with 6 time points (treated as a categorical variable as well). Basically I want to model the
2011 Aug 08
1
mixed model fitting between R and SAS
Hi al, I have a dataset (see attached), which basically involves 4 treatments for a chemotherapy drug. Samples were taken from 2 biopsy locations, and biopsy were taken at 2 time points. So each subject has 4 data points (from 2 biopsy locations and 2 time points). The objective is to study treatment difference.? I used lme to fit a mixed model that uses "biopsy.site nested within pid"
2008 Jul 09
4
Strptime/ date time classes
Dear all, I've come across a problem using strptime, can anyone explain what's going on? I'm using version 2.7.0 on Windows XP. Thank you Caroline First read in a data file using read.table alldata = read.table(file, header=F, skip=4, colClasses = c("character","numeric")) dim(alldata) [1] 223960 2 # inefficient, safe way of sorting out missing or dodgy
2008 Nov 19
2
simulation of autoregressive process
Dear R users, I would like to simulate, for 20000 replications, an autoregressive process: y(t)=0.8*y(t-1)+e(t) where e(t) is i.i.d.(0,sigma*sigma), Thank you in advance ____________________________________________________ Écoutez gratuitement le nouveau single de Noir Désir et découvrez d'autres titres en affinité avec vos goûts musicaux
2017 Jun 22
1
MODISTools Help
1. You should always cc the list unless there is a clear reason not to. 2. You still have failed to follow the posting guide: You say you have difficulty troubleshooting your code, but you have shown us no code. You got an error message that seems explicit, but with neither code nor data, I do not know whether anyone can make sense of it. In any case, I certainly cannot. Cheers, Bert Bert
2006 May 15
1
what's wrong with my "gls"? it does not allocate memory... even for the simplest AR1 model...
> myfit1 <- gls(col1 ~ col2+col3+col4+col5+col6-1, data=data2, corr=corAR1( 0.3202), method='ML') Error: cannot allocate vector of size 199712 Kb if I get rid of the "corr=corAR1(0.3202)" option, it works okay... can anybody help me? thanks a lot! [[alternative HTML version deleted]]
2001 Mar 28
4
fitting growth curves
Dear R-list members, Cynthia M. Jones wrote a paper (Fitting growth curves to retrospective size-at-age data, Fisheries Research 46(2000):123-129; abstract at http://www.elsevier.nl/gej-ng/10/19/44/70/24/37/abstract.html)where the SAS procedure MIXED, Macro NLINMIX (Littell et. al., 1996)was used to estimate the von Bertalanffy growth function parameters assuming that data from the same fish are
2017 Jun 23
1
MODISTools Help
On 6/22/2017 7:05 PM, Caroline wrote: > ##MODISTools example > library(MODISTools) > library(lubridate) > setwd('~/Documents/Modis data') > > #####MODISTools with buffalo data > > ###Read in data rename for easier coding > tbdata <- read.csv('~/Desktop/All TB data for EVI, NDVI.csv') Since this dataset is only on your desktop it cannot help us
2017 Jun 23
0
MODISTools Help
##MODISTools example library(MODISTools) library(lubridate) setwd('~/Documents/Modis data') #####MODISTools with buffalo data ###Read in data rename for easier coding tbdata <- read.csv('~/Desktop/All TB data for EVI, NDVI.csv') firstobs <- subset(tbdata, capture.ID == 'B1-1108') firstobs <- firstobs[,c(1,2,2,3,4)] colnames(firstobs) <- c('id',
2002 Sep 18
1
memory allocation
Dear all; I experienced a memory allocation error while running gnls: > wBlplfe.wc <- update(wBlplfe.w, corr=corAR1()) Error: cannot allocate vector of size 37950 Kb In addition: Warning message: Reached total allocation of 256Mb: see help(memory.size) Increased memory limit to 512, 640 M, the allocation error persisted: > memory.limit(512) NULL > wBlplfe.wc <-
2009 Sep 12
3
how to find maximum for multivariable data
Dear all, I have a data set as follows: ID cycle.number cycle.result 1 2525 1 38 2 2525 2 38 3 2525 3 25 4 2525 4 25 5 2525 5 25 6 2525