Displaying 8 results from an estimated 8 matches similar to: "Can't invert matrix"
2009 Oct 07
1
Buglet in qbeta?
Hi,
I sometimes play around with extreme parameters for distributions and
found that qbeta is not always monotone as the following example shows.
I don't know whether this is serious enough to submit a bug report (as
this example is near to the limitations of floating point arithmetic).
Josef
> x <- qbeta((0:100)/100,0.01,5)
> x
[1] 0.000000e+00 1.253990e-201 1.589622e-171
2011 Feb 10
2
R 2.12.1 Windows 32bit and 64bit - are numerical differences expected?
Should one expect minor numerical differences between 64bit and 32bit R on
Windows? Hunting around the lists I've not been able to find a definitive
answer yet. Seems plausible using different precision arithmetic, but waned
to confirm from those who might know for sure.
BACKGROUND
A colleague was trying to replicate some modelling results (from a soon to
be published book) using rpart, ada,
2012 Oct 07
1
variances of random effects in coxme
Dear R users,
I'm using the function coxme of the package coxme in order to build Cox
models with complex random effects. Unfortunately, I sometimes get
surprising estimations of the variances of the random effects.
I ran models with different fixed covariates but always with the same 3
random effects defined by the argument
varlist=coxmeMlist(list(mat1,mat2,mat3), rescale = F, pdcheck = F,
2009 Jun 30
1
possible agrep bug; R 2.9.1, Mac OS X 10.5 (PR#13789)
Same behavior was noted on R 2.9.0 OS X and WIndows.
> t(sapply(seq(0.01, .99, length=20), function(x) c(x, length(agrep("Staatssekretar im Bundeskanzleramt","Bundeskanzler",max.distance=x)))))
[1,] 0.01000000 0
[2,] 0.06157895 0
[3,] 0.11315789 0
[4,] 0.16473684 0
[5,] 0.21631579 0
[6,] 0.26789474 0
[7,] 0.31947368 0
[8,] 0.37105263 0
[9,]
2008 May 12
3
help with rpart
Hi,
I am using rpart as a part of my masters' project. I am trying to print out
the resulting model using plot() function along with text() function. I am
having difficulties with labels being cut-off. In text() function, I am
using use.n=T option to get the number of people in each nodes but the on
the lower and left part of the plot, the numbers get cut off. Thanks!
Linus
[[alternative
2011 Jan 26
1
Inconsistencies in the rpart.object help file?
Hello all,
I'm was going through the help for
?rpart.object
And noticed some inconsistencies, Some might be a mistake in the help file
and some might be my misunderstanding.
The help in the section:
value -> frame (first paragraph), states that:
> yval, the fitted value of the response at each node, *and splits, a two
> column matrix of left and right split labels for each node. *
2010 Apr 02
0
(no subject)
> I'm using rpart function for creating regression trees.
> now how to measure the fitness of regression tree???
>
> thanks n Regards,
> Vibha
I read R-help as a digest so often come late to a discussion. Let me
start by being the first to directly answer the question:
> fit <- rpart(time ~ age +ph.ecog,lung)
> summary(fit)
Call:
rpart(formula = time ~ age +
2009 Sep 24
1
Maximum likelihood estimation of parameters make no biological sense
R-help,
I'm trying to estimate some parameters using the Maximum Likehood method.
The model describes fish growth using a sigmoidal-type of curve:
fn_w <- function(params) {
Winf <- params[1]
k <- params[2]
t0 <- params[3]
b <- params[4]
sigma <- params[5]
what <- Winf * (1-exp(- k *(tt - t0)))^b