search for: minima

I am using numerical optimization to fit a 1 parameter model, in which the input parameter is bounded. I am currently using optimize(), however, the problem turns out to have local minima, and optimize does not always seem to find the global minimum. I could to write a wrapping function that tries multiple intervals or starting values, but I would prefer a package that has built-in methods to make it more robust against local minima. I checked the CRAN Task View for Optimization, h...

Dear R users, How to find all single minima within each next part of analyzed vector (table) Select all minima (mass_value=min & mass_value<2) (many) in vector(table), BUT first put mask on table in order to select within one window mask (5 elements) only one local minimum, and next to search within the next time window mask the s...

I have data in the form of (x,y) pairs and would like to find local minima and maxima (typically the zeros of the 2nd derivative) of the y values. I looked at numericDeriv, but I don't have an "expression" per se. I looked at optim, also, but it looks like it will find only one "global" max or min. I can code up my own piecewise derivatives,...

Hi there, I use the surf.gls() function to fit a variable measured over a surface. When I plot the predicted surface, there are local minima/maxima in almost every coordinate where data were measured, which seems aberrant. For instance: ?? x <- c(343,293,343,243,293,343,443,543,593,243,293,343,393,443,493,543,593,143,193,243,293,343,393,443, 493,543,593,193,243,293,343,543,593,643,93,193,243,293,343,393,443,493,543,43,93,143,193,2...

...I managed to apprximate a function. f <- approxfun(2:nrow(CB), CB[2:nrow(CB),2]) But how do I defferentiate f()? g<-deriv(f(2:nrow(CB)),"x") Did not work out for me, or at least, I dont know how to get those "x", with g(x)=0. My ultimate goal, is to find all the local minima of CB[,2]. (min() gives only the global minimum) Any suggestions how to do it? Thanks for your help in advance. Michael -- [[alternative HTML version deleted]]

Hello, I am trying to use optim() on a function involving a summation. My function basically is a thinned poisson likelihood. I have two parameters and in most cases optim() does a fine job of getting the minima. I am simulating my data based on pre specified parameters, so I know what I should be getting. However when my true parameters fall in a particular range, optim() gives incorrect results. I have generated a grid of parameter values and calculated my likelihood through those to see that the...

...aying a chart. like : send_data(g.to_blob, :filename => "any.png", :type => ''image/png'', :disposition=> ''inline'') I actually do a <img src="http://myhost:3000/stats/make_graph" /> Is there any way more clean to do that ? At minima don''t hardcode the beginning of the url (host:port) I''ve tried a bit ''render'' w/o success. Thanks

...eate.signalSeries(aa, pos=list(from=0.0, by=0.033)) aa.cwt <- wavCWT(aats) x11 (width=10,height=12) plot (aats,main=paste(insig," Cycle: ",j,sep="")) aa.maxtree <- wavCWTTree (aa.cwt, type="maxima") aa.mintree <- wavCWTTree (aa.cwt, type="minima") aa.maxpeak <- wavCWTPeaks (aa.maxtree) aa.minpeak <- wavCWTPeaks (aa.mintree) Error in `row.names<-.data.frame`(`*tmp*`, value = c("1", "0")) : invalid 'row.names' length bb <- -aa #EXCHANGE MAXIMA WITH MINIMA bbts <- create.signalSeri...

...wn strategy based on the Akaike's and Schwarz's information criteria in the datails to the ADF.test function. What does a "top-down strategy" mean? Probably the respective criterion is minimized and the mode vector contains the lag orders at which the criterion attains it local minima? When the calculation is over, the ADF.test function gives info about "Lag orders". What are these lag orders? Are they the local minima of the criterion? I will be very thankful if you clarify this to me. I browsed a lot, but I could not find a clear answer. Thank you for your at...

...um points (turning points) are of interest to me. Reading these dates and counts off from the plot is difficult as I am dealing with a large data. I have been looking at turnpoints function in pastecs library but have not been able to figure out the appropriate commands that one can use to find the minima/maxima (turning points) or pits/peaks in a series. My data is of the form shown below where y stands for year, m month, d day and finally count. Is there a way I could find these minima together with the dates they occurred? I would be indebted to those of you who will show me the way out of these...

> On Jul 30, 2015, at 12:20, Warren Young <wyml at etr-usa.com> wrote: > > Meanwhile over here in CentOS land, you still see SSH password guessers banging on every public IP that responds to port 22. Why? Because it still occasionally works. Increase the password strength minima, and this class of worm, too, will quickly die out. If the Windows fix was firewall on by default, why isn?t that the appropriate ?fix" for Linux distros? Why mess with the password strength or which daemons are running? Seems like it adds the necessary step of ?STOP: If you turn off this,...

...s, the problem I've been grappling with für quite some time now is the following: I have a 100 rows x 200 columns matrix. data.set <- matrix(rnorm(20000, 100, 200)) Now I would like to get a vector of length 100 which collects the values from the following procedure: Take the sum of the minima of the two values from each row of columns 1 and 101, and divide it by the sum of column 101. Do the same for column 2 and 102, 3 and 103 and so on. Thanks a lot for your help. Alrik ******************************************* Alrik Thiem Research Assistant WEC E17 Weinbergstrasse 11 Center for...

Hi, did the search and didn't find an answer. For months now most of my windows apps, running on a minima xmonad system move slowly down down down and always to the right side. I thought, maybe some .dlls needed. I thought, maybe it's that I don't use a full desktop environment and prefer a windows manager instead (xmonad) love to know what causes this. So, basically almost anything I open (r...

Dear All, I'm trying to maximize a likelihood with respect one parameter using "optimize" on simulated data (without error component). I've iterated the maximization procedure 1000 times and I should always obtain the same estimate of the parameter (equal to the simulated one) but, instead, i obtain different results (the likelihood function shouldn't be flat). Does

...questions: 1. Has (and if so how has) the criterion to be modified, if i estimate the transformations of the variables too? 2. How is the usage of the criterion if i use dummy variables (for categorical data) in the model? 3. does the criterion have only one minimum, or may i assume several local minima? Thank you in advance Thomas -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !...

Hi Jean Marc & List, So I have been fiddling with the denoiser (again). While poking around I noticed that nb_preprocess is basically a counter that is mod-ded with 100 (the default), which causes Smin[] to be re- seeded with the value in Stmp[] (min of the previous adaptation period). Smin[] is then used to update the noise probability, which is (probably) less likely when adaptation

The documentation says, "pmax and pmin take several vectors as arguments and return a single vector giving the parallel maxima (or minima) of the vectors." I discovered that, if you use a matrix or array instead of a vector, pmax returns a matrix or array, respectively. This makes pmax and pmin much more useful, and should not be left to people to discover on their own! For example: m1 <- array(1:24,c(2,3,4)) m2 <- arra...

...$ floor : num 0 0.106 0 231 231 0.011 0 0 0 100 ... $ ceiling : num 0.005 0.106 1 231 231 0.011 0.001 0.002 0.001 100 ... The logical 'preeq0' separates sampdate into two groups; 'ceneq1' indicates censored/uncensored values; 'floor' and 'ceiling' are the minima and maxima for censored values. The NADA package methods will be used, but I have not found information on whether this format or the wide (i.e., spreadsheet) format should be used. The NADA.pdf document doesn't tell me; at least, I haven't found the answer there. I can apply reshape2 t...

On Wed, February 4, 2015 17:55, Warren Young wrote: > > But of course the same people fighting this move to more secure > password minima are the same ones that turn off SELinux. > Ah. Sorry, NO. First, we are not talking about a more secure password minima. We are discussing an arbitrary change made to an installer program that adversely impacts usability and that only has a tenuous connection to security on a production syste...