Displaying 20 results from an estimated 9000 matches similar to: "Help with constrained optimization"
2009 Jul 01
2
Difficulty in calculating MLE through NLM
Hi R-friends,
Attached is the SAS XPORT file that I have imported into R using following code
library(foreign)
mydata<-read.xport("C:\\ctf.xpt")
print(mydata)
I am trying to maximize logL in order to find Maximum Likelihood Estimate (MLE) of 5 parameters (alpha1, beta1, alpha2, beta2, p) using NLM function in R as follows.
# Defining Log likelihood - In the function it is noted as
2012 Oct 23
1
Minimizing Computational Time
Dear R-users,
May I seek some suggestions from you. I have a long programme written in R
with several 'for' loops inside. I just want to get them out by any elegant
way (if there is!) to reduce the computational time of the main programme.
For instance, is there any smart way for the following programme that will
lessen time?
2013 Mar 11
2
vertical lines in R plot
Dear All,
May I seek your suggestion on a simple issue. I want to draw vertical lines
at some positions in the following R plot. To be more specific, I wish to
draw vertical lines at d=c(5.0,5.5,6) and they should go till
p=c(0.12,0.60,0.20) . I haven't found any way out, though made several
attempts. Please run the following commands first if you are interested in!
2012 Mar 19
1
Linear regression
Hello there,
I am new to using regression in R. I wanted to solve a simple regression
problem where I have 2 equations and 2 unknowns.
So lets say -
y1 = alpha1*A + beta1*B
y2 = alpha2*A + beta2*B
y1 <- runif(100000, 0,1)
y2 <- runif(100000,0,1)
alpha1 <- 0.6
alpha2 <- 0.75
beta1 <- 1-alpha1
beta2 <- 1-apha2
I now want this equation to estimate the values of A and B. Both A
2008 Jan 04
2
R2WinBUGS sending variables as factors
Hello R and BUGS users,
I am writing a heirarchical model in R to send to BUGS via R2WinBUGS and
I am finding it difficult to get the model to run. I seem to be having
two problems.
1) I can't seem to send variables classed as factors (Month), is there a
way do this?
2) Checking the Log in WinBUGS I can see that the model is Syntactically
correct, but Bugs is not able to recognise the the
2006 Jul 22
1
ifelse command
Dear:
I try to revise the maximum likelihood function below using something constrains. But it seems something wrong with it. Becasue R would not allow me to edit the function like this. It is very appreciate if you can help.
function (parameters,y,x1,x2)
{
p<-parameters[1]
alpha1<-parameters[2]
beta1<-parameters[3)]
delta1<-parameters[4]
alpha2<-parameters[5]
2006 Jul 22
1
Why the contrain does not work for selecting a particular range of data?
Dear:
Continuing the issue of 'ifelse'! I selecting the data whose 'x2'=1 for maximizing likelihood. I used two way to do this but the results are different.
1.Way one I use the data for x2=1 and run the program. It works for me. Tthe program is described as below:
function (parameters,y1,x11)
{
p<-parameters[1]
alpha1<-parameters[2]
beta1<-parameters[3]
2009 Oct 23
3
v2.0.alpha2 released
http://dovecot.org/releases/2.0/alpha/dovecot-2.0.alpha2.tar.gz
http://dovecot.org/releases/2.0/alpha/dovecot-2.0.alpha2.tar.gz.sig
Changes since alpha1:
- All debug messages are now logged to debug log (debug_log_path
setting, defaults to info_log_path). Patch by Pascal Volk.
- Added support for SORT=DISPLAY IMAP extension.
- Added doveadm who command for listing currently logged in users.
2007 Aug 07
1
v1.1.alpha2 released
http://dovecot.org/releases/1.1/alpha/dovecot-1.1.alpha2.tar.gz
http://dovecot.org/releases/1.1/alpha/dovecot-1.1.alpha2.tar.gz.sig
Hopefully the next release can be v1.1.beta1. I'm not aware of any major
problems and I think I'm pretty much done with new features (except for
dbox).
The largest changes since alpha1:
* Removed THREAD indexing. It's a bit buggy and I think
2005 Dec 13
1
fSeries
I'm trying to use garchFit from fSeries, with Student or Skewed Student conditionnal distribution. Let's say that eps (vector) is my series of daily log-returns:
data(EuStockMarkets)
eps = diff(log(EuStockMarkets[,"CAC"]))
library(fSeries)
g = garchFit(series = eps, formula.var = ~garch(2,2), cond.dist = "dstd")
s = g at fit$series
All the coefficients are ok
2008 Jul 29
1
Howto Draw Bimodal Gamma Curve with User Supplied Parameters
Hi,
Suppose I have the following vector (data points):
> x
[1] 36.0 57.3 73.3 92.0 300.4 80.9 19.8 31.4 85.8 44.9 24.6 48.0
[13] 28.0 38.3 85.2 103.6 154.4 128.5 38.3 72.4 122.7 123.1 41.8 21.7
[25] 143.6 120.2 46.6 29.2 44.8 25.0 57.3 96.4 29.4 62.9 66.4 30.0
[37] 24.1 14.8 56.6 102.4 117.5 90.4 37.2 79.6 27.8 17.1 26.6 16.3
[49] 41.4 48.9 24.1
2005 Mar 02
1
Warning: number of items to replace is not a multiple of replacement length
I feel like a complete dolt, as I know this question has been asked by
others on a fairly regular basis, but I'm going in circles trying to get
the following to work:
id.prob<-function (tt)
{
library(mvtnorm)
#============================
Makeham<-function(tt)
{
a2=0.030386513
a3=0.006688287
b3=0.039047537
t<-tt-20
h.t<-a2+a3*exp(b3*t)
S.t<-exp(-a2*t+a3/b3*(1-exp(b3*t)))
2011 Aug 11
1
R crashes when communicating with JAGS
There is a thread on this topic already:
http://finzi.psych.upenn.edu/Rhelp10/2010-August/250934.html
I'm rather mystified by a similar problem and wondering whether I've
overlooked something obvious. I'm running with latest versions of R and
all packages, and latest version of JAGS running under Windows 7.
Here's the problem. I have some source code. It's given below -
2004 Jun 22
2
function not in load table
Hi,
I apologize for this often/old question. I found some hints but couldn't
solve the problem so far.
I have C functions (incl. the header files) as well as the R wrapper
functions which I want to use for faster calculations. These functions
are included in a R package.
The installation process seems to be ok (no errors). I also can load the
package without errors. But when I call the
2005 Sep 14
2
SSL/TLS stopped working in 1.0 alpha2
I have both 1.0 alpha1 and alpha2 installed on my test mail server.
SSL/TLS does not work on alpha2. I'm using the same config file for
both. No errrors in dovecot.log either. Is there a way to increase
debugging info without recompiling?
2007 Jul 26
2
error in using R2WinBUGS on Ubuntu 6.10 Linux
I am trying to run WinBUGS 1.4 from the Ubuntu 6.10 Linux distribution. I am using the R2WinBUGS packages with the source file listed below. WinBUGS appears to run properly, but I get the following message after WinBUGS starts in WINE. Does anyone know what may be causing this error and what the correction may be?
Thanks
ERROR MESSAGE:
fixme:ole:GetHGlobalFromILockBytes cbSize is 13824
2005 Mar 24
1
How to stop the minimization when the condition does not hold
Dear experts!
I have a minimization problem with non-linear constraint and Objective
function(theta)=lambda*(Constr)^2-f(x,theta). Theta is a vector of
parameters.
I'd like to stop the optimization after the value of the constraint is less
or equal some constant value, say d, and save the last computed value of the
function.
For this purpose, I thought to define the Objective function like
2009 Nov 24
1
Titles in plots overlap
Hi,
I use fCopulae package to draw different graphs of univariate and bivariate skew t. But the plots titles overlap. I tried using cex.main, font.main to adjust the size but they still overlaps. Here is my code:
par(mfrow = c(3, 1))
mu = 0
Omega = 1
alpha1 = 0
alpha2 = 1.5
alpha3 = 2
alpha4 = 0.5
Z1 = matrix(dmvst(x, 1, mu, Omega, alpha1, df = Inf), length(x))
Z2 = matrix(dmvst(x, 1, mu,
2004 May 06
5
Orthogonal Polynomial Regression Parameter Estimation
Dear all,
Can any one tell me how can i perform Orthogonal
Polynomial Regression parameter estimation in R?
--------------------------------------------
Here is an "Orthogonal Polynomial" Regression problem
collected from Draper, Smith(1981), page 269. Note
that only value of alpha0 (intercept term) and signs
of each estimate match with the result obtained from
coef(orth.fit). What
2011 May 04
1
hurdle, simulated power
Hi all--
We are planning an intervention study for adolescent alcohol use, and I
am planning to use simulations based on a hurdle model (using the
hurdle() function in package pscl) for sample size estimation.
The simulation code and power code are below -- note that at the moment
the "power" code is just returning the coefficients, as something isn't
working quite right.
The