search for: stochastic

Displaying 20 results from an estimated 324 matches for "stochastic".

2009 Oct 15
4
Generating a stochastic matrix with a specified second dominant eigenvalue
Hi, Given a positive integer N, and a real number \lambda such that 0 < \lambda < 1, I would like to generate an N by N stochastic matrix (a matrix with all the rows summing to 1), such that it has the second largest eigenvalue equal to \lambda (Note: the dominant eigenvalue of a stochastic matrix is 1). I don't care what the other eigenvalues are. The second eigenvalue is important in that it governs the rate at wh...
2008 Jan 14
1
stochastic growth rate (package biopop)
...t;. In a deterministic model {i.e., transition matrix is defined as A <- matrix(c(0.70, 0.70,0.35,0.50), nrow=2,byrow=TRUE}, population growth rate can be estimated from the dominant eigenvalue {command "eigen.analysis"}. However, I cannot figure out the way to compute the asymptotic stochastic population growth rate using ?popbio?. I would like to perform a stochastic model in which my demographic rates are sampled from beta distribution with known mean and SD. For example, rather than 0.50 (4th term of my matrix), I want to sample this parameter from a beta function at each time-step {e...
2009 Apr 26
1
Stochastic Gradient Ascent for logistic regression
Hi. guys, I am trying to write my own Stochastic Gradient Ascent for logistic regression in R. But it seems that I am having convergence problem. Am I doing anything wrong, or just the data is off? Here is my code in R - lbw <- read.table("http://www.biostat.jhsph.edu/~ririzarr/Teaching/754/lbw.dat" , header=TRUE) attach(lbw)...
2010 Feb 12
1
popbio and stochastic lambda calculation
Hello R users, I am trying to calculate the stochastic lambda for a published matrix population model using the popbio package. Unfortunately, I have been unable to match the published results. Can anyone tell me whether this is due to slightly different methods being used, or have I gone wrong somewhere in my code? Could the answer be as simple a...
2000 Aug 22
0
Using RNG from MS [forwarded message from Xiaoqiang Li]
...rror message and the C codes are shown below. Could you give me some suggestions? Thanks a lot for your help. ************************************************************************* *************** error message ********************************** Linking... Creating library Release/stochastic.lib and object Release/stochastic.exp stochastic.obj : error LNK2001: unresolved external symbol _PutRNGstate stochastic.obj : error LNK2001: unresolved external symbol _unif_rand stochastic.obj : error LNK2001: unresolved external symbol _Rf_rnorm stochastic.obj : error LNK2001: unresolved externa...
2013 Apr 25
1
Stochastic Frontier: Finding the optimal scale/scale efficiency by "frontier" package
Hi, I am trying to find out the scale efficiency and optimal scale of banks by stochastic frontier analysis given the panel data of bank. I am free to choose any model of stochastic frontier analysis. The only approach I know to work with R is to estimate a translog production function by sfa or other related function in frontier package, and then use the Ray 1998 formula to find th...
2008 Feb 07
2
where do I find stochastic volatilities models in R or Matlab?
Hi all, Does anybody have the source code of stochastic volatility models in R or Matlab, for example, the Bayesian based or the simulation based SV estimations as described by Prof Eric Zivot in the following discussion? https://stat.ethz.ch/pipermail/r-sig-finance/2005q4/000501.html -------------- I am wondering what is the current status of estima...
2008 May 29
1
package for stochastic frontier models?
I need to estimate maximum tree crown radius and am looking for a package to prepare stochastic frontier models in R. I have not found any package references on Nabble R help, google, or R help. Any tips on a package for this? With regards, Aaron Trowbridge Researcher BV Research Centre Smithers B.C. -- View this message in context: http://www.nabble.com/package-for-stochastic-fronti...
2011 Feb 10
0
stochastic growth models
Hello, It's not easy to express clearly what I have in mind by stochastic growth models. I've been working with a couple of titles -Stochastic Models in Biology, for one, but both date back a decade or more. I'll try to illustrate the model a little more. A reasonably comparable situation is Bolker's analysis of how many flowers are created on a given plant...
2011 Apr 10
1
look for the package of latent class stochastic frontier
Dear all, I want to finished my paper by latent class Stochastic Frontier Analysis , but i can not find the package, is there anyone that may help me Thanks a lot. [[alternative HTML version deleted]]
2009 Aug 30
1
Stochastic (transition) matrices: how to determine distributions and variance?
(apologies for the cross-posting, and for this being a more general stats question rather than a specific-to-R one. I assure you I will be doing the actual analysis in R :) I am trying to determine the distribution and variance for a classic stochastic (transition) matrix problem such that: let x(t) be an initial state vector consisting of counts of classes A, B and C: x(t) = [A(t),B(t),C(t)] T is the stochastic (transition) matrix for these classes consisting of the transition probabilities between each combination of A,B and C: pAA p...
2008 Nov 08
0
New package "frontier" for Stochastic Frontier Analysis (SFA)
Hi! A few weeks ago, I have uploaded a new R package "frontier" for Stochastic Frontier Analysis (SFA) [1] to CRAN [2]. It includes the FORTRAN code of Tim Coelli's [3] software "Frontier 4.1" [4]. Hence, the R package "frontier" should have the same capabilities as "Frontier 4.1", i.e. Maximum Likelihood Estimation of Stochastic Frontier...
2006 Nov 16
2
Stochastic SEIR model
Dear colleagues, I?m a new R-help user. I?ve read the advertisements about the good manners and I hope to propose a good question. I?m using R to build an epidemiological SEIR model based on ODEs. The odesolve package is very useful to solve deterministic ODE systems but I?d like to perform a stochastic simulation based on Markov chain Montecarlo methods. I don?t know which packages could be used to do it (I tried with "sde" but without results). Have you some suggestions about useful methods and/or function in R for reaching my aim. Thanks in advance. Max MASSIMO FENATI (DVM) --...
2008 Feb 24
0
where can I find source code for particle filters applied to stochastic volatilities?
Hi all, Could anybody point me to some overview/survey papers about using particle filters and sequential monte carlo methods to estimate stochastic volatilities? I couldn't find any such articles giving a big-picture view of the literature. How do these estimation methods compare to EMM and other Bayesian methods for estimating stochastic volatilities? Also, I am looking for some sample/source code that shows how to program particle filt...
2008 Nov 08
0
New package "frontier" for Stochastic Frontier Analysis (SFA)
Hi! A few weeks ago, I have uploaded a new R package "frontier" for Stochastic Frontier Analysis (SFA) [1] to CRAN [2]. It includes the FORTRAN code of Tim Coelli's [3] software "Frontier 4.1" [4]. Hence, the R package "frontier" should have the same capabilities as "Frontier 4.1", i.e. Maximum Likelihood Estimation of Stochastic Frontier...
2010 Feb 21
1
Tutorials and scripts of Stochastic Frontier Analysis and Linear Programming.
Dear all, I want to program my own models about Stochastic Frontier Analysis and Linear programming (Data Envelopment Analysis). In this context, is there anyone that may help me with some simple tutorials and scripts about these issues? Thanks a lot. -- Marcus Vinicius Pereira de Souza, Prof. [[alternative HTML version deleted]]
2008 May 25
1
n Realizations of a Stochastic Process assigned to dynamically generated variable names?
I am interested in creating multiple (say 1000) time series, from a given stochastic process, of length 250. I want to refer to each realization with its own variable name, of the format say, tsn, where n is the n'th simulation. i.e. ts1, ts2, ts3, ts4, .... , ts1000 The way I am thinking of doing this is placing the following code within another loop, and the 'tsn' as...
2003 Apr 15
1
Simulation of Stochastic processes
Hi: I was wondering whether I can find some help for computer simulation of stochastic processes (e.g. Brownian motion), for pedagogicl/instructional purposes. Any help would be appreciated. thanks, Ravi.
2007 Oct 23
1
multivariate Stochastic Volatility and GARCH
Dear everyone, i`m a german economics student, writing my masterĀ“s thesis about "Multivariate Volatility Models". After having read about theoretical aspects of Multivariate GARCH ans Stochastic Volatility Models, I would like to compare DCC-GARCH and DC-SV with help of an empirical application. I figuered out that one has to use MCMC-simulation-methods for that. Some days ago I started searching the internet for already written codes... without any succes. The only code I found is from Yu...
2013 Dec 11
0
Stochastic Dominance Analysis
Do anyone now R packages that run/test stochastic dominance with respect to a function (SDRF) and/or stochastic efficiency with respect to a function (SERF)? Peter Maclean Department of Economics UDSM [[alternative HTML version deleted]]