Displaying 20 results from an estimated 7000 matches similar to: "random number generator"
2000 Jan 24
2
help in fortran code
I would like to get the fortran code for the functions locpol and dpill
in the kernsmooth library , the purpose is to incorporate other
selection criterion for the bandwidth in which a varying bandwidths are
replaced instead of the constant bandwidth. I will send you back the
improved version as soon as I get the fortran code for the upper mention
functions. ((LOCPOLY and DPILL )))
2018 Jul 07
3
Completar un for, que falla al faltarle algún dato.
Buenas noches;
Además del proyecto que comenté antes y con el que sigo discutiendo,
también me estoy peleando con otro... con el que también tropiezo.
Necesito reordenar los datos presentados en dos columnas a filas y
columnas.
Los datos ideales serían algo así:
Ques <- c(rep("Q1",3),rep("Q2",3),rep("Q3",3))
Info <- rep(c("aca", "ahi",
2011 Aug 02
1
How to 'mute' a function (like confint())
Dear R-helpers,
I am using confint() within a function, and I want to turn off the message
it prints:
x <- rnorm(100)
y <- x^1.1+rnorm(100)
nlsfit <- nls(y ~ g0*x^g1, start=list(g0=1,g1=1))
> confint(nlsfit)
Waiting for profiling to be done...
2.5% 97.5%
g0 0.4484198 1.143761
g1 1.0380479 2.370057
I cannot find any way to turn off 'Waiting for. .."
I tried
2011 Feb 16
3
Loooooong logon-times using samba 3.5.6 and Windows 7
Dear samba-users
We are experiencing some rather long logon times using SAMBA 3.5.6 on Debian Squeeze + Windows 7 and while trying to find out why we raised the loglevel to 5 resulting in a rather large logfile. But this did give us a hint as to why we experience so long logon times. It seems that samba is going through the whole user-database with all usernames and machine-accounts.
Eventually
2003 Nov 25
5
Parameter estimation in nls
I am trying to fit a rank-frequency distribution with 3 unknowns (a, b
and k) to a set of data.
This is my data set:
y <- c(37047647,27083970,23944887,22536157,20133224,
20088720,18774883,18415648,17103717,13580739,12350767,
8682289,7496355,7248810,7022120,6396495,6262477,6005496,
5065887,4594147,2853307,2745322,454572,448397,275136,268771)
and this is the fit I'm trying to do:
nlsfit
2012 Jul 11
2
nls problem: singular gradient
Why fails nls with "singular gradient" here?
I post a minimal example on the bottom and would be very
happy if someone could help me.
Kind regards,
###########
# define some constants
smallc <- 0.0001
t <- seq(0,1,0.001)
t0 <- 0.5
tau1 <- 0.02
# generate yy(t)
yy <- 1/2 * ( 1- tanh((t - t0)/smallc) * exp(-t / tau1) ) + rnorm(length(t))*0.01
# show the curve
2011 Jun 16
1
Need help with config file
Thank you for your time...we made some changes to our config file and the
server doesn't want to start with the command icecast -c
/path/to/icecast.xml giving the error:
'Could not create listener socket on port 8000 Server startup failed.
Exiting'
can you look at the config file bellow and let us know of any changes that
might help. we need to be able to have 10,000 clients
2013 Sep 27
3
Compare species presence and absence between sites
Dear List,
I want to compare the presence and absence of bird species based on the
sites in a matrix.
The matrix has 5 rows for Island A, B, C, D, and E.
It has 100 columns for bird species D001-D100.
In each cell of the matrix,
the presence-absence of bird species will be recorded as 1 or 0.
(For example, if species D001 is found on Island D,
the matrix cell of species D001 and Island D
2004 Feb 02
3
mvrnorm problem
I am trying to simulate draws from a multivariate normal using mvrnorm, and
am getting the following error message:
Error in mu + eS$vectors %*% diag(sqrt(pmax(ev, 0)), p) %*% t(X) :
non-conformable arrays
I do not understand why I am getting this message, since the vector of means
I am giving to the function is 13 by 1 and the variance matrix I am giving
to the function is 13
2008 Jun 26
2
constructing arbitrary (positive definite) covariance matrix
Dear list,
I am trying to use the 'mvrnorm' function from the MASS package for
simulating multivariate Gaussian data with given covariance matrix.
The diagonal elements of my covariance matrix should be the same,
i.e., all variables have the same marginal variance. Also all
correlations between all pair of variables should be identical, but
could be any value in [-1,1]. The problem I am
2005 May 01
2
eigen() may fail for some symmetric matrices, affects mvrnorm()
Hi all,
Recently our statistics students noticed that their Gibbs samplers were
crashing due to some NaNs in some parameters. The NaNs came from
mvrnorm (Ripley & Venables' MASS package multivariate normal sampling
function) and with some more investigation it turned out that they were
generated by function eigen, the eigenvalue computing function. The
problem did not seem to happen
2011 Jan 22
1
faster mvrnorm alternative
Hello,
does anybody know another faster function for random multivariate normal
variable simulation? I'm using mvrnorm, but as profiling shows, my algorithm
spends approximately 50 % in executing mvrnorm function.
Maybe some of you knows much faster function for multivariate normal
simulation?
I would be very gratefull for advices.
--
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2007 Oct 06
1
Tricky vectorization problem
Hi all,
I'm using the code below within a loop that I run thousands of times
and even with the super-computing resources at my disposal this is
just too slow. The snippet below takes about 10s on my machines,
which is an order of magnitude or two slower than would be
preferable; in the end I'd like to set the number of monte carlo
experiments to 1e4 or even 1e5 to ensure stable
2011 Jul 06
1
Create simulated data's using mvrnorm
Hi All
This might be something very trivial but I seem to miss something in the
syntax or logic which makes me keep wandering around the problem without
arriving at a solution.
What I want to do is to simulate a sample data for performing cluster
analysis. I tried to use
x1= mvrnorm(10,rep(0.8,3),diag(3))
x2= mvrnorm(10,rep(0,3),diag(3))
x3= mvrnorm(10,rep(-0.5,3),diag(3))
x=rbind(x1,x2,x3)
2008 Jul 05
5
help about random generation of a Normal distribution of several variables
Hello.
Somebody knows how can I generate a set of n random vectors of a
normal distribution of several variables?
For example, I want to generate n=100 random vectors of two dimensions
for a normal with mean c(0,1) and variance matrix:
matrix(c(2,1,1,3),2,2).
Thanks in advance,
Arnau.
2011 Feb 24
3
problem in for loop
Hi all.
I was having some trouble with a for loop and I found the problem is the
following.
Does anyone have some idea why I got the following R result? Since mone
is equal to 3, why
mu1 only have 2 components?
library(MASS)
> p0 <- seq(0.1, 0.9,by=0.1)
> m <- 10
>
>
> p0 <- p0[7]
>
> ## data generation
>
> mzero <- p0*m
> mone <- m-mzero
>
2003 May 06
4
Questons about R capabilities
Hello,
1) I am interested in performing a limited-dependent variable linear regression. By this I mean a classical linear regression, but for the case where the values of the dependent variable cannot vary from -infinity to +infinity, but are truncated and so are between two finite limits L1 and L2. Does R1.7 have this capability? If so what is (are) the relevant command(s)?
2) I am also
2011 May 01
1
Urgent: conditional formula for nls
I have data vectors x and y both with 179 observations. I'm trying to
fit a nonlinear model with five parameters using nls. The formula is
only defined within a range of x-values, it should be zero otherwise,
thus my attempted use of ifelse:
> df<-data.frame(x,y)
>
2013 May 25
1
Generating random numbers satisfying specific regression equation
Hello everybody
Sorry if such a question has already been posted somewhere, but I wasn’t able to find an answer yet.
I’m trying to generate random numbers for illustration purposes.
The random numbers should satisfy a multiple regression equation, for example:
z = 0.3 + 0.05 * x + 1.5 * y + 3 * xy
I was playing around with mvrnorm (MASS), but since I’m still a newbie to R and not an educated
2005 Jan 06
2
Generating Data mvrnorm and loops
Dear List:
I am generating N datasets using the following
Sigma<-matrix(c(400,80,80,80,80,400,80,80,80,80,400,80,80,80,80,400),4,4
)
mu<-c(100,150,200,250)
N=100
for(i in 1:N)
{
assign(paste("Data.", i, sep=''),
as.data.frame(cbind(seq(1:1000),(mvrnorm(n=1000, mu, Sigma)))))
}
With these datasets, I need to work on some of the variables and then
run each dataset