Displaying 20 results from an estimated 3000 matches similar to: "Subsetting a matrix"
2010 Jul 19
1
packet loss on ixgbe using vlans and ipv6
Hi,
I have a Dell T710 with 4 X 10G ethernet interfaces (2 X Dual port Intel
82599 cards). It is running FreeBSD RELENG_8 last updated on July 13.
What I see is packet loss (0 - 40%) on IPv6 packets in vlans, when the
machine is not the originator of the packets.
Let me try to describe a little more. If a neigbouring machine ping6 it,
there will be packet loss. If it act as a router for ipv6,
2010 Jun 12
2
Logic with regexps
Greetings,
The following question has come up in an off-list discussion.
Is it possible to construct a regular expression 'rex' out of
two given regular expressions 'rex1' and 'rex2', such that a
character string X matches 'rex' if and only if X matches 'rex1'
AND X does not match 'rex2'?
The desired end result can be achieved by logically combining
2013 Apr 16
2
efficiently diff two data frames
Dear all,
What is the quickest and most efficient way to diff two data frames,
so as to obtain a vector of indices (or logical) for rows/columns that
differ in the two data frames? For example,
> Xe <- head(mtcars)
> Xf <- head(mtcars)
> Xf[2:4,3:5] <- 55
> all.equal(Xe, Xf)
[1] "Component 3: Mean relative difference: 0.6863118"
[2] "Component 4: Mean relative
2009 Sep 19
1
Re-order columns
Dear R'sians,
Would really appreciate if you could suggest a more efficient way to order
the columns of a dataset. The column names of the dataset contain indices
separated by a period. Following are examples of my code and the dataset.
oC <- function(tg=x2) {
lth <- length(grep("T",names(tg)))
thix <-
2013 May 15
1
still mbuf leak in 9.0 / 9.1?
Hi list,
since we activated 10gbe on ixgbe cards + jumbo frames(9k) on 9.0 and now on 9.1 we recognize that after a random period of time, sometimes a week, sometimes only a day, the
system doesn't send any packets out. The phenomenon is that you can't login via ssh, nfs and istgt is not operative. Yet you can login on the console and execute commands.
A clean shutdown isn't possible
2005 Oct 10
1
using innov in arima.sim
Hello,
I have used the arima.sim function to generate a lot of time series, but to day I got som results that I didn't quite understand. Generating two time series z0 and z1 as
eps <- rnorm(n, sd=0.03)
z0 <- arima.sim(list(ar=c(0.9)), n=n, innov=eps)
and
z1 <- arima.sim(list(ar=c(0.9)), n=n, sd=0.03),
I would expect z0 and z1 to be qualitatively similar. However, with n=10 the
2008 Dec 11
2
how to get the CDF of a density() estimation?
Hi,
I've estimated a simple kernel density of a univariate variable with
density(), but after I would like to find out the CDF at specific
values.
How can I do it?
thanks for your help, with it I am very close to finish my first
little bit more serious work in R,
Viktor
2003 Apr 24
5
Fast R implementation of Gini mean difference
I have written the following function to calculate the weighted mean
difference for univariate data (see
http://www.xycoon.com/gini_mean_difference.htm for a related
formula). Unsurprisingly, the function is slow (compared to sd or mad)
for long vectors. I wonder if there's a way to make the function
faster, short of creating an external C function. Thanks very much
for your advice.
gmd
2006 Sep 01
1
integration problem with gamma function
Dear R-list members,
I have a problem with translating a mathematica script into R. The whole
script is at the end of the email (with initial values for easy
reproduction) and can be pasted directly into R. The problematic part
(which is included below of course) is
<--- Original Mathematica --->
(* p_svbar *)
UiA = Ni (Dsi - 2Di A + A^2)/2;
UiiA = Nii (Dsii - 2Dii A + A^2)/2;
psvbar =
2003 May 20
4
Output to connections
In the document "R Data Import/Export", section "Output to connections",
there is the following portion of code:
## convert decimal point to comma in output, using a pipe (Unix)
zz <- pipe(paste("sed s/\\./,/ >", "outfile"), "w")
cat(format(round(rnorm(100), 4)), sep = "\n", file = zz)
close(zz)
## now look at the output
2003 Jul 15
0
Multivariate regression method
Hi Folks,
Thanks to several people's suggestions and clarifications,
I think I have implemented a function which computes the
conditional mean and covariance matrix of a subset of the
dimensions of an MV-normal variable, given the values on the
other dimensions (these conditioning value can be presented
as a matrix, to deal with several cases at once).
The code is below, for anyone who would
2003 May 13
2
RMySQL crashes R
I have justed upgraded R v1.7.0 on Windows NT 4 and have installed the
latest RMySQL (version 0.5-1)and DBI (version 0.1-5) packages.
When I issue the following commands (tactfully adjusted) R just crashes and
disappears, any ideas?
require(RMySQL)
m <- dbDriver("MySQL")
con <- dbConnect(m, dbname="xxx", user="xxx", password="xxx",
2005 Sep 01
5
Multivariate Skew Normal distribution
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Caio Lucidius
> Naberezny Azevedo
> Sent: 01 September 2005 12:09
> To: Help mailing list - R
> Subject: [R] Multivariate Skew Normal distribution
>
>
> Hi all,
>
> Could anyone tell me if there is any package (or function)
2006 Feb 21
1
color quantization / binning a variable into levels
Hi all,
I'd like to quantize a variable to map it into a limited set of integers
for use with a colormap. "image" and filled.contour" do this mapping
inside somewhere, but I'd like to choose the colors for plotting a set of
polygons. Is there a pre-existing function that does something like this
well? i.e., is capable of using 'breaks'?
2005 Nov 08
1
Output glm
Hello,
How can I obtain the likelihood ratio of a Poisson regression model?
Regards.
_____________________________________________
dr. Marziliano Ciro
Facolta' di Economia
Universita' degli Studi di L'Aquila
p.zza del Santuario, 19
67040 Roio Poggio, L'Aquila
tel.: 0862 434836
fax: 0862 434803
2003 Jun 10
2
fitting data to exponential distribution with glm
I am learning glm function, but how do you fit data using exponential
distribution with glm?
In the help file, under "Family Objects for Models", no ready made option
seems available for the distribution as well as for other distributions
satisfying GLM requirements not listed there.
2006 Feb 15
1
distribution fitting
Dear list,
Does anyone know how to fit the power law distribution?
I have the empirical distribution and would like to check whether it fits
the power law (with the power estimated from the data).
Any hints are appreciated.
Tanks a lot!
Galina
[[alternative HTML version deleted]]
2006 Feb 15
1
using kernel density estimates to infer mode of distribution
Hello...
Is it possible to use "density" or another kernel density estimator to
identify the mode of a distribution? When I use 'density', the resulting
density plot of my data is much cleaner than the original noisy histogram,
and I can clearly see the signal that I am interested in. E.g., suppose my
data is actually drawn from two or more normal (or other)
2009 Jul 06
1
transform multi skew-t to uniform distribution
Hi R-users,
I have a data from multi skew t and would like to transform each of the data to uniform data. I tried using 'pmst' but only got one output:
> rr1 <- as.vector(r1);rr1
[1] 0.7207582 5.2250906 1.7422237 0.5677233 0.7473555 -0.6020626 -2.1947872 -1.1128313 -0.6587316 -1.1409261
> pmst(rr1, xi=rep(0,10), Omega=diag(10), alpha=rep(1,10), df=5)
[1] 3.676525e-09
2006 Jan 23
1
mutlivariate normal and t distributions
Dear R-help list members,
I have created a package 'mnormt' with facilities for the multivariate
normal and t distributions. The core part is simply an interface to
Fortran routines by Alan Genz for computing the integral of two
densities over rectangular regions, using an adaptive integration
method. Other R functions compute densities and generate random
numbers.
The starting