Displaying 20 results from an estimated 6000 matches similar to: "manipulating elements of a matrix"
2004 May 27
2
manipulating elements of a vector
Dear R users;
I would like to convert a series of vectors to matrices in the following
way;
(2,1,1) to a matrix
1 0 0
1 0 0
0 1 0
0 0 1
The idea is that the column sum of the matrix should be equal to the
elements of the vector.
Thanks.
Vumani
2003 Jan 22
1
something wrong when using pspline in clogit?
Dear R users:
I am not entirely convinced that clogit gives me the correct result when I
use pspline() and maybe you could help correct me here.
When I add a constant to my covariate I expect only the intercept to change,
but not the coefficients. This is true (in clogit) when I assume a linear in
the logit model, but the same does not happen when I use pspline().
If I did something similar
2004 Mar 25
3
subsetting based on vector
Dear R users;
I am trying to write a small program which reads in a data set, and selects
observations from certain years before the analysis. I have a problem
including the selection criteria in the header of the program.
Here is the problem;
dataFIT<-function(MODEL, MARGINS, yearConsidered){
library(foreign
CovPaper<-read.spss("C:/Data/data.sav")
NewData <-
2005 Mar 23
4
sampling from a mixture distribution
Dear R users,
I would like to sample from a mixture distribution p1*f(x1)+p2*f(x2). I
usually sample variates from both distributions and weight them with their
respective probabilities, but someone told me that was wrong. What is the
correct way?
Vumani
2006 Mar 08
2
fitting a distribution using glm
it is easy to fit a distribution using fitdistr
poisdata <- rpois(n = 100, lambda = 2)
poismle <- fitdistr(poisdata, "Poisson")
poismle
but i would like to know whether its possible to get an identical result
using glm. I use
poistab <- data.frame(table(poisdata))
colnames(poistab) <- c("width","freq");
poistab[,"width"] <-
2005 Aug 04
2
drawing a network digraph
Dear R users,
I have a matrix with 2 columns with the variables: "daughter index", "mother
index". I would like to draw a network digraph using this data, where each
daughter is connected to a mother and between the connections inlcude a
circle with the information on the indices ("daughter index", "mother
index"): i.e. something similar to graphs
2003 Jun 16
1
Hmisc multiple imputation functions
Dear all;
I am trying to use HMISC imputation function to perform multiple imputations
on my data and I keep on getting errors for the code given in the help
files.
When using "aregImpute" the error is;
>f <- aregImpute(~y + x1 + x2 + x3, n.impute=100)
Loading required package: acepack
Iteration:1 Error in .Fortran("wclosepw", as.double(w), as.double(x),
2003 Jan 20
1
R analogue
Dear R users:
Is there any R analogue for the S+ function "na.gam.replace". I would like
to make an interaction of a categorical and smooth continuous covariate.
Thanks.
Vumani Dlamini
Central Statistical Office
Swaziland
2005 Nov 21
2
Multinomial Nested Logit package in R?
Dear R-Help,
I'm hoping to find a Multinomial Nested Logit package in R. It would
be great to find something analogous to "PROC MDC" in SAS:
> The MDC (Multinomial Discrete Choice) procedure analyzes models
> where the
> choice set consists of multiple alternatives. This procedure
> supports conditional logit,
> mixed logit, heteroscedastic extreme value,
2007 Jun 20
2
"xtable" results doesn't correspond to data.frame
Dear useRs,
Am trying to use xtable on the following data.frame and I don't get what I
expect:
example.table <- data.frame(rbind(
c("Gender"," "," "," "),
cbind(rep(" ",2),c("Male","Female"),c(3.0,4.0),c(3/7,4/7))
))
colnames(example.table) <- c(" "," ","number of
2003 Aug 20
1
query on converting survey data from one structure to another
Dear R users,
I am trying to convert a dataset from one format to several rectangular
datasets. A consultant helped design the data entry program for our survey
using Delphi/Pascal and for each household the information is stored in a
file called "EA-HM-HH.TXT" where EA is the enumeration area number, HM is
the homestead number and HH is the household number. Within this file the
2003 Jan 17
2
Re: Universal legend in plot
Dear R-users:
I asked a question on how I can have a universal legend in a plot and
received the following result. I tried using "layout" but I can't seem to
work on the "empty" plot (where I have to have the legend). I tried "oma"
but I couldn't improve the quality of the plot, and that I didn't know how
to specify all the line types using the
2005 Jun 01
1
"\n" in legend using substitute and as.expression
Dear R users,
Is it possible to force a hard return in an expression. I tried including
one for a legend using an expression and it didn't work. Here is my code,
legend(12, 0.10, c("Fitted density",
as.expression(substitute(paste("Weibull (", alpha==shapeU," , ",
beta==scaleU,") Mean = ",meanU," days"),
list(shapeU =
2006 Jun 29
1
using "rbinom" in C code gives me erroneous results... random variable is not random (always zero)...
Dear Listers,
I am trying to use "rbinom" in my C code, but i always get zeros as output no matter the probability. Am not sure what I am doing wrong because the function has worked before. Attached in an example. Noticed that "rbinom" expects 'n' to be REAL.
Regards, Vumani
R 2.3.1 (2006-06-01)
Windows XP
Gcc
/* Called this file binom.c and then ran rcmd shlib on it
2003 Jan 17
0
Re: Universal legend in plot
Is your data such that it can be restructured into a form amenable to a
lattice plot, such as xyplot()? In that case, the legend (key in lattice)
can be placed pretty much anywhere.
Regards,
Andrew C. Ward
CAPE Centre
Department of Chemical Engineering
The University of Queensland
Brisbane Qld 4072 Australia
andreww at cheque.uq.edu.au
On Friday, January 17, 2003 10:22 PM, Vumani Dlamini
2006 Jul 05
1
i suspect that there a memory leak in "vmmin"?
Dear listers,
Am currently using MCMC approaches to estimate some parameters of my model.
One parameter has to be updated using a tuned gamma distribution. So at each
iteration I estimate the mean and variance of the density of the gamma
approximation using "vmmin" (i also supply the gradient argument). For
moderate replications the procedure works, but if I increase them R crashes.
2002 Jul 29
0
multinomial probit
Is there any library for fitting multinomial probit using either likelihood
or the "method of simulated moments" or both.
I presume it would be possible to write a family function in VGAM for the
multinomial probit, but was hoping that someone has done it already.
Thanking you as always.
Vumani Dlamini
CSO-Swaziland
2009 Apr 23
2
Two 3D cones in one graph
Dear R-users:
The following code produces two cones in two panels. What I would like
to have is to have them in one, and to meet in the origin. Does anyone
have any good ideas how to do this?
Thanks for your help
Jaakko
library(lattice)
A<-matrix(ncol=2, nrow=64)
for(i in 0:63)
{
A[i+1,1]<-sin(i/10)
A[i+1,2]<-cos(i/10)
}
2011 Feb 07
1
multiple imputation manually
Hi,
I want to impute the missing values in my data set multiple times, and then
combine the results (like multiple imputation, but manually) to get a mean
of the parameter(s) from the multiple imputations. Does anyone know how to
do this?
I have the following script:
y1 <- rnorm(20,0,3)
y2 <- rnorm(20,3,3)
y3 <- rnorm(20,3,3)
y4 <- rnorm(20,6,3)
y <- c(y1,y2,y3,y4)
x1 <-
2008 Aug 15
1
estimating the proportion without recurring ailment based on the nelson-aalen estimator
Dear useRs,
I'm trying to estimate the proportion of individuals with a without a certain recurring ailment at several times points. The data are of the survival type, with "start"-"stop" dates and whether the individual had the ailment in that interval.
Some cases are observed until database closure and some died or are lost to followup. The interest is not on death. I