search for: logarithm

Hello, in scilab /Matlab there are functions that can create linear sequences (like R's seq()) as well as logarithmic sequences. Is there a logarithmic aequivalent of seq()? Or maybe this would be an idea for newer R-releases, maybe a type-option with "linear" and "logarithmic" as parameters....?! Ciao, Oliver

Hello I want to calculate natural logarithm of sum of combinations as follow: (R code) { com_sum=choose(2000000,482)*choose(1000000,118)+choose(2000000,483)*choose(1000000,117)+...+choose(2000000,i)*choose(1000000,600-i)+...+choose(2000000,600)*choose(1000000,0) #calculate the sum result=log(com_sum)...

Hi, In order to use the mle2-function, one has to define the likelihood function itself. As we know, the likelihood function is a sum of the logarithm of probability density functions (pdf). I have implemented myself the pdfs that I am using. My problem is, that the pdfs values are negative and I cann't take the logarithm of them in the log-likelihood function. So how can one take the logarithm of negative values of the pdfs? Thanks a lot...

Hi, I have some questions for the wireframe function of the lattice package. My dataset's "x-data" are sampled logarithmically and as such I would like to have a semilogarithmic 3D plot when plotting a time series. Does anyone know how to change the example in http://addictedtor.free.fr/graphiques/sources/source_40.R such that x or y would be logarithmically scaled? Also, I would like to change the color scale such...

Dear Researches, sorry for the easy and common question. I am trying to justify the idea of RandomForest don't require a transformations (e.g. logarithmic) of variables, comparing this non parametrics method with e.g. the linear regressions. In leteruature to study my phenomena i need to apply a logarithmic trasformation to describe my model, but i found RF don't required this approach. Some people could suggest me text or bibliography to study...

...logaritmic y-axis with the base of e. When I type "log="y"", the axis transforms into a logaritmic axis with the base of 10. Best regards, Elisabeth > Dear Elisabeth, > > I'm not sure if I have understood your question -- are you trying > to use a different logarithmic base? > > Kind regards, > > Xianwen > > On Sun, May 9, 2010 at 8:05 PM, Elisabeth Bjerke Rastad > <ebr024 at post.uit.no> wrote: >> Hello! >> &g...

Dear R-help, Here's a simple example of nonlinear curve fitting where nls seems to get the answer wrong on a very simple exponential fit (my R version 2.7.2). Look at this code below for a very basic curve fit using nls to fit to (a) a logarithmic and (b) an exponential curve. I did the fits using self-start functions and I compared the results with a more simple fit using a straight lm() command. The logarithmic fit works 100% correctly below. The problem is with the exponential fit: the nls command gives the wrong values and I have comp...

How can perform logarithmic binning in the scatterplot? I could only take the log of the variables and plot them, but I am sure that is not the way. I have a very huge data, and would want to plot those high density scatterplots and code then with different colors for the bins/density. -- View this message in context: http...

...ake a (more or less) 2-d histogram, and for the most part it's working fine with my data. However, I can't get the color key to do what I need. I can give it labels and custom cutoffs, but my cutoff lines (and hence my labels) aren't evenly spaced, instead they're more-or-less logarithmic, starting at [0,20,50,100...] and continuing on up to 5 million. Levelplot scales the ticks/labels linearly on the color key, leaving most my labels scrunched down atop each other at the bottom and only the last few (..."500K","1M","2M","5M") really vis...

...de: library(vioplot) x1 <- GSMrxDL x2 <- WIFI x3 <- UMT vioplot(x1, x2, x3, ylim=c(0, 10), names=c("GSMrxDL", "WIFI", "UMT"), col="gold") title("NIS Strahlung", xlab="Sender", ylab="V/m") Now I want to scale the y-axis logarithmically, i.e. 0.01; 0.1; 1; 10. How can I do this? Thank you very much Alex --

Hi, In continuation of the discussion of melange comments,about negative value returned in matcher due to logarithm of probabilities. *I**f we make K suitably large, we could clamp each log(K.Pi) to be >= 0, and this change will only affect really low probability terms (those with Pi < 1/K, so you can adjust K to suit):* *W' = sum(i=1,...,n, max(log(K.Pi), 0))* Did you mean for low probability the t...

This should be simple but I am struggling. I like to easily switch in xyplot between a linear or logarithmic y-axis by setting a logical flag logY to False or True. This switch changes the scales argument of xyplot. I found out that the original two-dimentional data (Conc vs Time in my case) are converted to log10(Conc) if log=TRUE in scales, but it appears that functions like panel.curve need to provid...

...around with the Ajax.PeriodicalUpdater. In looking at the API, I''m liking the decay option -- not necessarily for my current purpose, but just to keep in mind -- and I have a question: can the decay be a function which returns an integer? Basically, why I''m looking for is a logarithmic decay (where the system updates a lot right after a change but then slows down the frequency of updates but not to be slower than the horizontal asymptote of the logarithm used). Using a function to produce a logarithmic series of integers wouldn''t be a problem, but can that functi...

Hi there, I guess this must be a standard issue, but I'm starting to go crazy with it. I simply want a plot with the x axis being logarithmic, having labels 1, 10, 100..., and ten unlabelled ticks between each of them - just as they introduce logarithmic axis at school. I've played around a bit with log="x", xlog=T (where exactly is the difference here?), xaxp, and xaxt (unfortunately xaxt="l" isn't impl...

...pr","fpr") plot( perf1, type="l",col=1 ) auc1 <- performance(pred1,"auc") auc1 <- auc1@y.values[[2]] " 2. I have to compare two models that have very close ROCs. I'd like to have a more distinguishable plot of the ROCs. So is it possible to have a logarithm FP axis which might probably separate them well? Or zoom in the part close to the leftup corner of ROC plot? Or any other ways to make the ROCs more separate? Thanks and regards! --Tim [[alternative HTML version deleted]]

Hi! I'm using a large panel data, and now I have faced some difficulties with my analysis. The predictors are not normally distributed and there are quite many outliers (some of them are influential though). I have tried to change the logarythm, but i'm not sure, how to do that. I want also draw a plot picture in which logarythms of predictors x and y are changed. How could I do that?

Hi everyone, I am new in R, just used it for 2 weeks and I have a basic question. I have data, for example table$attrib that I would like to plot its cumulative distribution in logarithmic scale. How do I do that? After browsing internet, I tested this command: > plot.ecdf(1:100, log ="y", table$attrib) I got a plot, but I am not really sure what 1:100 and log="y"did to produce the plot. Any help is appreciated. Thank you, Zuki

> My question is not about statistics but more obviously about an R command. > I would like to plot an histogram with a logarithmic scale. I have > searched through R documentation and have read about the "log" option. > What matters is that it does not work with the hist() function. I'm > working with R version 1.2.3 . Maybe the problem has been solved in R 1.3 > . > Thanks for your help, > Re...

Dear R-helpers! Using logarithmic axes sometimes results in an odd labelling. In some cases, only half of the axes do have labels. Hmmmm. I've played around with par(lab=c(5,5,7)) but that didn't help. An example: ---- begin example ---- x <- c(0.12, 0.3, 0.53, 1.1, 1.8, 2.6, 4.5) y <- c(0.012, 0.021, 0....

...orm(1000), freq=FALSE, seq(-4, 4, .5), ylim=c(0.001, 0.5), log="y") Which gives the expected histogram but also warnings for my log="y" command (""log" is not a graphical parameter in: axis(side, at, labels, tick, line, pos, outer, font, lty, lwd, ") and no logarithmic y-axis. Any ideas how to achieve that, I couldn't find anything? Best regards David *************************************************************** Dr. David Bolius Agroscope Reckenholz-T?nikon ART Gruppe Lufthygiene/Klima Reckenholzstrasse 191, CH-8046 Z?rich Tel. ++41 (0)44 / 377 75...