Displaying 15 results from an estimated 15 matches for "discretisation".
2008 Jan 22
1
ODE's in R
...d up in using R for this job, in the first
place!)
More precisely, does anybody know any technical issue that could make
the work insecure in the sense of propagation of errors? Is there any
track of evidence that R is, in this kind of task, less reliable than
e.g. MatLab? We use just a simple discretisation written in a for loop
and a variable (i.e. user-fed) time step.
Maybe, I'm too neurotic about this, but I guess I just want some comfort
after seeing a few particularly nasty orbits.
Best,
Markku Karhunen
National Public Health Institute,
Finland
2010 Mar 11
1
Dicrete Laplace distribution
Hello,
<http://tolstoy.newcastle.edu.au/R/help/04/07/0312.html#0313qlink1> Could
anybody tell me how to generate discrete Laplacian distribution?
I need to sample uma discretised Laplacian density like this:
J( g -> g´) ~ exp (-lambda | g´ - g |) g in {0,…, gmax}
Thanks,
Nicolette
[[alternative HTML version deleted]]
2002 Mar 26
3
ks.test - continuous vs discrete
I frequently want to test for differences between animal size frequency
distributions. The obvious test (I think) to use is the Kolmogorov-Smirnov
two sample test (provided in R as the function ks.test in package ctest).
The KS test is for continuous variables and this obviously includes length,
weight etc. However, limitations in measuring (e.g length to the nearest
cm/mm, weight to the nearest
2010 Nov 14
5
kalman filter
Hello,
I would like use Kalman filter for estimating parameters of a stochastic
model. I have developed the state space model but I don’t know the correct
way use Kalman filter for parameter estimation. Has anybody experience in
work with Kalman filter in R.
I don’t know the correct function. Maybe it is
- KalmanLike; but what is the correct Input?
- tsmooth?
-
2001 Apr 23
3
missing ctest and methodological question
Hi,
I couldn't figure out how to use the functions from the
ctest library. I'm using the r-base package that comes with
debian potato. library("ctest") told me that no such package
existed. I checked the CRAN, but no such package was
availiable, instead I was told that it would be part of the
standard installation. But functions from ctest like
shapiro-wilk don't work. The
2009 Apr 04
1
Problem with sample()
Hi,
I'm having a problem using sample() within a function.
Basically I get an error reading:
Error in sample(v, 1, prob = h) : non-positive probability
Can anyone advise me as to the possible origin of this error?
Here is my code
#Discretised Gillespie algorithm function (From SMfSB, D.J. Wilkinson)
gillespied=function (N, T=100, dt=1, ...)
{
tt=0
n=T%/%dt
x=N$M
2000 May 04
0
About Omega in pda()
...riminant analysis with the fda() function, but I don''t know all the details of splines theory.
I try on the example of the phonems from the article "Penalised Discriminant Analysis" of Hastie, Buja and Tibshirani 1994 : 5 groups and 256 variables.
The 256 variables are from the discretisation of log-periodogram. Consequently, we want the scores to be smoothed by the frequency.
in continuus writing, J(beta)= integral of the square second derivative of beta upon the frequencies
and J(beta)=(beta)^T*OMEGA*beta
No function for producing one dimensional penalty object is providing with ge...
2004 Nov 24
12
scatterplot of 100000 points and pdf file format
Hi,
I want to draw a scatter plot with 1M and more points and save it as pdf.
This makes the pdf file large.
So i tried to save the file first as png and than convert it to pdf.
This looks OK if printed but if viewed e.g. with acrobat as document
figure the quality is bad.
Anyone knows a way to reduce the size but keep the quality?
/E
--
Dipl. bio-chem. Witold Eryk Wolski
MPI-Moleculare
2009 Feb 25
0
ggplot2 0.8.2
ggplot2 ------------------------------------------------------------
ggplot2 is a plotting system for R, based on the grammar of graphics,
which tries to take the good parts of base and lattice graphics and
avoid bad parts. It takes care of many of the fiddly details
that make plotting a hassle (like drawing legends) as well as
providing a powerful model of graphics that makes it easy to produce
2009 Feb 25
0
ggplot2 0.8.2
ggplot2 ------------------------------------------------------------
ggplot2 is a plotting system for R, based on the grammar of graphics,
which tries to take the good parts of base and lattice graphics and
avoid bad parts. It takes care of many of the fiddly details
that make plotting a hassle (like drawing legends) as well as
providing a powerful model of graphics that makes it easy to produce
2013 Jan 22
2
Approximating discrete distribution by continuous distribution
Dear all,
I have a discrete distribution showing how age is distributed across a
population using a certain set of bands:
Age <- matrix(c(74045062, 71978405, 122718362, 40489415), ncol=1,
dimnames=list(c("<18", "18-34", "35-64", "65+"),c()))
Age_dist <- Age/sum(Age)
For example I know that 23.94% of all people are between 0-18 years, 23.28%
2008 Feb 26
4
"Raw" histogram plots
Hello
I need to plot a histogram, but insted of using bars, I'd like to plot
the data points. I've been doing it like this so far:
h <- hist(x, plot = F)
plot(y = x$counts / sum(x$counts),
x = x$breaks[2:length(x$breaks)],
type = "p", log = "xy")
Sometimes I want to have a look at the "raw" data (avoiding any kind of
binning). When x
2002 Feb 22
2
errors in integrate function?
I have been trying the integrate function in R, a function which would be
very useful for a current project of mine. But I am encountering errors
integrating the one function I have tried. The function to be integrated is
a product of a gamma demsity and a normal density:
gamma.by.normal_function(y,x,shape,scale,stdev)
return( dgamma(y,shape=shape,scale=scale)*
2009 Apr 08
3
MLE for bimodal distribution
Hello everyone,
I'm trying to use mle from package stats4 to fit a bi/multi-modal
distribution to some data, but I have some problems with it.
Here's what I'm doing (for a bimodal distribution):
# Build some fake binormally distributed data, the procedure fails also with
real data, so the problem isn't here
data = c(rnorm(1000, 3, 0.5), rnorm(500, 5, 0.3))
# Just to check
2010 Nov 24
0
4. Rexcel (Luis Felipe Parra)-how to run a code from excel
...iven by
>
>
>
> x[t]=A[t]*x[t-1]+B[t]*epsilon[t]
>
> y[t]=C[t]*x[t]+eta[t]
>
>
>
> A, y, B and C are Matrices. Y[t] is the data input vector with 800
> elements
> (every t has one element)
>
>
>
> My Model is described by the following
> (discretisation<http://www.dict.cc/englisch-deutsch/discretisation.html>)
> stochastic differential equation
>
>
>
> Lambda[t]=lambda[t-1]+kappa*lambda[t]*delta_t+epsilon_l
>
> R[t]=R[t-1]+mu*delta_t+epsilon_r
>
> epsilon_l=sigma_l*sqroot(delta_t)
>
> epsilon_r=sigma_r*...