search for: inadmissible

Displaying 11 results from an estimated 11 matches for "inadmissible".

2011 Sep 13
1
estimating Fstats in strucchange
Hi, I am new to R. It would be kind if I could get some help on this. I am using R to estimate Fstats but I am getting following error. a3 is annual GDP data from 1951 to 2010. > fs<- Fstats(ecm.model, from=1954, to = 1975,data=a3) Error in Fstats(ecm.model, from = 1954, to = 1975, data = a3) : inadmissable change points: 'from' is larger than 'to' In addition: Warning
2011 Oct 19
1
list of operations that preserve attributes
...nd gradients that use try() to check for computable functions. I'm also trying to do scaling as per optim() so that a number of methods that are available on CRAN and R-Forge can use parameter and function scaling. This got me into minor trouble when I scaled a gradient or Hessian and the "inadmissible" attribute I had created suddenly disappeared. When I discovered why -- that some operations don't preserve attributes -- I started to look for a list of which ops preserve attributes and which don't. The code snippet below shows that matrix multiplication (%*%) does not, while multipl...
2011 Nov 22
1
help to setting a multiple (linear) regression model with a 5% significance level (threshold) for the inclusion of the model variables.
Dear Researchers, someone know the right syntax to chose a 5% significance level (threshold) for the inclusion of the model variables in a multiple (linear) regression in backward way? I set the formula in this way, but I don't know to choose the 5% significance? lmodelV <- step(lm(formula=MyFormula[[1]],data=LR.train),direction="backward") thanks in advance gianni
2010 Apr 03
0
Restricting optimisation algorithm's parameter space
...rithm's parameter space so it does not search negative values when using GNLM? Are there other Libraries that Fit Non-linear models and allow for one to control the parameter space the search algorithm is restricted by? There are two issues here: 1) Rendering optimization codes resistant to inadmissible parameter vectors (sqrt of negatives etc.) 2) Providing constraints, particularly parameter bounds, on parameter inputs to optimization. There is quite a lot of activity going on right now with optimization in R. With Ravi Varadhan, Kate Mullen and Paul Gilbert, I've been putting some codes...
2008 Apr 17
3
Samba 3: bad read performance
??Hi all! We use Samba 3 server for some video stuff (editing, rendering, and so on) -- that's why performance is critical. We've tried a lot smb.conf options, but Samba can't satisfy our requirements. Our server configuration is as following: * Hard drive: RAID5 (8 x Seagate 7200.10), 3ware 9550SX-8LP controller * NICs (trunked): 2 x Broadcom NetXtreme BCM5704 * Processor: Opteron
2009 Dec 06
5
optim with constraints
Hi, dear R users I am a newbie in R and I wantto use the method of meximum likelihood to fit a Weibull distribution to my survival data. I use "optim" as follows: optim(c(1, 0.25),weibull.like,mydata=mydata,method="L-BFGS-B",hessian = TRUE) My question is: how do I setup the constraints so that the two parametrs of Weibull to be pisotive? Or should I use other function
2011 Jun 14
1
Using MLE Method to Estimate Regression Coefficients
Good Afternoon, I am relatively new to R and have been trying to figure out how to estimate regression coefficients using the MLE method. Some background: I am trying to examine scenarios in which certain estimators might be preferred to others, starting with MLE. I understand that MLE will (should) produce the same results as Ordinary Least Squares if the assumption of normality holds. That
2013 Oct 20
5
nlminb() - how do I constrain the parameter vector properly?
Greets, I'm trying to use nlminb() to estimate the parameters of a bivariate normal sample and during one of the iterations it passes a parameter vector to the likelihood function resulting in an invalid covariance matrix that causes dmvnorm() to throw an error. Thus, it seems I need to somehow communicate to nlminb() that the final three parameters in my parameter vector are used to
2009 Jan 27
2
optim() and ARIMA
dhabby wrote: Last week I run in to a lot a problems triyng to fit an ARIMA model to a time series. The problem is that the internal process of the arima function call function "optim" to estimate the model parameters, so far so good... but my data presents a problem with the default method "BFGS" of the optim function, the output error looks like this:
2007 Feb 07
2
some megatec-usb issues
...atter is powered off. My tests show that the driver gets "UPS No Ack" in about 17,5% of all requests. This is quite a huge value because every time the data gets stale I have some log records. The result is great log pollution. There would be several thousands of records per day. This is inadmissible for just a buggy hardware. Also the driver sometimes refuses to start if there are too many failed attempts during driver startup. My solution is to try to get descriptor again without delay in the same get_data call. You may think this way is not good because it will increase number of errors bec...
2001 Sep 14
5
Our Sympathies
The following is a message to be sent to the President of the United States of America. Although we may not be able to do a great deal from where we are, but for the people of America just knowing we care and feel their sadness will help. Please put your name on the following list and send it to all you know and who care. If you are the 100th name and every 100th there on could you please also