search for: isella

Displaying 20 results from an estimated 32 matches for "isella".

2012 Oct 05
2
Test for Random Points on a Sphere
Dear All, I implemented an algorithm for (uniform) random rotations. In order to test it, I can apply it to a unit vector (0,0,1) in Cartesian coordinates. The result is supposed to be a set of random, uniformly distributed, points on a sphere (not the point of the algorithm, but a way to test it). This is what the points look like when I plot them, but other then eyeballing them, can anyone
2011 Dec 15
3
From Distance Matrix to 2D coordinates
Dear All, I am struggling with the following problem: I am given a NxN symmetric matrix P ( P[i,i]=0, i=1...N and P[i,j]>0 for i!=j) which stands for the relative distances of N points. I would like use it to get the coordinates of the N points in a 2D plane. Of course, the solution is not unique (given one solution, I can translate or rotate all the points by the same amount and generate
2010 Jul 19
1
Hurst Exponent Estimation
Dear All, I am a novice when it comes to time-series analysis and at the moment I am actually interested in calculating the Hurst exponent of a time series. This question has already been asked quite some time ago http://bit.ly/98dZsi and I trust some progress has been made ever since. I was able to find some functions in the packages
2013 Jan 28
1
RandomForest and Missing Values
Dear All, I would like to use a randomForest algorithm on a dataset. The set is not particularly large/difficult to handle, but it has some missing values (both factors and numerical values). According to what I found https://stat.ethz.ch/pipermail/r-help/2005-September/078880.html https://stat.ethz.ch/pipermail/r-help/2007-January/123117.html
2016 Apr 19
0
Problem with X11
I don't have my debian box available so can't confirm. But I would try $apt-get install libpng On Tue, Apr 19, 2016 at 11:23 AM, Lorenzo Isella <lorenzo.isella at gmail.com> wrote: > Dear All, > I have never had this problem before. I run debian testing on my box > and I have recently update my R environment. > Now, see what happens when I try the most trivial of all plots > > plot(seq(22)) >> > Error in (...
2016 Apr 19
3
Problem with X11
Dear All, I have never had this problem before. I run debian testing on my box and I have recently update my R environment. Now, see what happens when I try the most trivial of all plots > plot(seq(22)) Error in (function (display = "", width, height, pointsize, gamma, bg, : X11 module cannot be loaded In addition: Warning message: In (function (display = "", width,
2017 Nov 07
0
Fitdistrplus and Custom Probability Density
...ight require some fiddling e.g. d <- function(x) { exp(-x^2/2)/(sqrt(2*pi)) } # just an example for you to test with; use your own density d(x) in your case Then define myCumDist, myQuantile as above and compare with pnorm, qnorm. HTH, Eric On Tue, Nov 7, 2017 at 4:22 PM, Lorenzo Isella <lorenzo.isella at gmail.com> wrote: > Dear All, > Apologies for not providing a reproducible example, but if I could, then I > would be able to answer myself my question. > Essentially, I am trying to fit a very complicated custom probability > distribution to some data. >...
2017 Nov 07
2
Fitdistrplus and Custom Probability Density
Dear All, Apologies for not providing a reproducible example, but if I could, then I would be able to answer myself my question. Essentially, I am trying to fit a very complicated custom probability distribution to some data. Fitdistrplus does in principle everything which I need, but if require me to specify not only the density function d, but also the cumulative p and and inverse cumulative
2018 Apr 18
3
Reasons to Use R in a Public Administrations and Ideas for a Short Training
Dear All, Ages ago I posted to this mailing list asking for advice about to evangelize the use of R in an international public administration where the fact that R is free is not a decisive factor (actually its being "freeware" may even be seen negatively). After a long time, I think it is worthwhile asking the question again and see what suggestions other users have. Another question
2009 Apr 01
1
Latex symbols in R (\perp and \parallel)
Dear All, I am sure this is a one-liner, but I cannot find the R command to generate the LaTex symbols \perp and \parallel. Consider for instance the figure (one can use any kind of data for the plot) pdf("friction_linear_chain_perpendicular.pdf") par( mar = c(4.5,5, 2, 1) + 0.1) plot(data[ ,1], data[
2010 Jun 23
5
Plotrix Trick
Dear All, I am using the plotrix library to plot some matrices. I have a problem: some of my data are outliers, hence using a linear color scale does not work very well (you would see too many cells having a similar, indistinguishable color). See the code snipped at the end of the email. Plotting the logarithm of the data gets the job done, but my problem is that I would like to write in every
2007 Mar 01
2
function with Multiple Output
Dear R user, I have a simple question for you: I have created a global function that evoke other subsidiary functions. when I run the global function I want to store the outcomes of the of each subsidiary function into a variables. an examples my.fun=function(vector, index){ a=fun.a(vector, index) b=fun.b(vector, index) } if i use return() I can only retrive one single results.
2012 Feb 19
1
World Heat/Rainbow Map
Dear All, I would like to do the following: make a plot of the world and color a few selected states. Some states have an associated scalar (i.e a simple number) and I would like to paint them using a heat map and show legend for the color map in the plot. One or two states do not have any number associated to them and are simply colored/filled according to a distinctive pattern that I choose.
2013 Mar 24
1
Random Forest, Giving More Importance to Some Data
Dear All, I am using randomForest to predict the final selling price of some items. As it often happens, I have a lot of (noisy) historical data, but the question is not so much about data cleaning. The dataset for which I need to carry out some predictions are fairly recent sales or even some sales that will took place in the near future. As a consequence, historical data should be somehow
2017 Dec 21
1
Fitting Beta Distribution
Dear All, I need to fit a custom probability density (based on the symmetric beta distribution B(shape, shape), where the two parameters shape1 and shape2 are identical) to my data. The trouble is that I experience some problems also when dealing with the plain vanilla symmetric beta distribution. Please consider the code at the end of the email. In the code, dbeta1 is the density of the beta
2017 Dec 21
0
Fitting Beta Distribution
...tor is also a function of the parameters I want to optimise, hence I should write dbeta2 <- function(x, shape){ res <- x^(shape-1)*(1-x)^(shape-1)/beta(shape, shape) return(res) } after which the results are consistent. ---------- Forwarded message ---------- From: Lorenzo Isella <lorenzo.isella at yopmail.com> Date: 21 December 2017 at 11:29 Subject: Fitting Beta Distribution To: "r-help at r-project.org" <r-help at r-project.org> Dear All, I need to fit a custom probability density (based on the symmetric beta distribution B(shape, shape), where th...
2017 Jun 25
1
rJava Broken on Linux + R 3.4
Dear All, I think there is something wrong with rJava on any Debian based distribution. I may be wrong, but I experiencing exactly the problems mentioned at https://github.com/amattioc/SDMX/issues/130 and at https://github.com/s-u/rJava/issues/110 A couple of packages (RJSDMX and xlsx) are now impossible to install on my debian stretch platform
2011 Feb 25
2
Visualizing Points on a Sphere
Dear All, I need to plot some points on the surface of a sphere, but I am not sure about how to proceed to achieve this in R (or if it is suitable for this at all). In any case, I am not looking for really fancy visualizations; for instance you can consider the images between formulae 5 and 6 at http://bit.ly/hOgK9h Any suggestion is appreciated. Cheers Lorenzo
2016 Apr 19
0
Problem with X11
...???? [11] LC_MEASUREMENT=de_DE.UTF-8??? LC_IDENTIFICATION=de_DE.UTF-8attached base packages:[1] stats???? graphics? grDevices utils???? datasets? methods?? base???? other attached packages:[1] rkward_0.6.1loaded via a namespace (and not attached):[1] tools_3.0.2Best regards,Markus HofstetterLorenzo Isella <lorenzo.isella at gmail.com> schrieb (19.04.2016 17:23):Dear All, I have never had this problem before. I run debian testing on my box and I have recently update my R environment. Now, see what happens when I try the most trivial of all plots > plot(seq(22)) Error in (function (display =...
2012 Dec 30
3
Odds Ratio and Logistic Regression
Dear All, I am learning the ropes about logistic regression in R. I found some interesting examples http://bit.ly/Vq4GgX http://bit.ly/W9fUTg http://bit.ly/UfK73e but I am a bit lost. I have several questions. 1) For instance, what is the difference between glm.out = glm(response ~ poverty + gender, family=binomial(logit), data=mydata) and glm.out =