search for: borchers

Displaying 20 results from an estimated 66 matches for "borchers".

2008 Nov 28
7
Examples of advanced data visualization
...rovide a good paradigm. I would be interested even if it will not be easy to implement such examples in R, e.g. because of the interactive nature of these graphical displays. Please answer to my e-mail address. In case enough interesting material comes up, I will enter a summary here. Hans Werner Borchers ABB Corporate Research
2008 Jul 08
4
Histogram with colors according to factor
...like 'lattice' and 'ggplot2'. Searching R-help revealed that 'histogram' is spelled 'histogramm' in almost 2% of the time. I now know how to color whole bars, but did not find a solution for this specific kind of visualization. Many thanks in advance, Hans Werner Borchers ---- Hans W. Borchers ABB Corporate Research ----- ---- Hans W. Borchers ABB Corporate Research Germany -- View this message in context: http://www.nabble.com/Histogram-with-colors-according-to-factor-tp18336930p18336930.html Sent from the R help mailing list archive at Nabble.com.
2009 Aug 07
2
R patched & devel versions as portable ZIP files
...those running R from an USB stick because otherwise you have to install it on the disk---what maybe you don't want to do---and then copy it over to the stick. I know there are some concerns with R-(D)COM interface and i assume those using it know which versions to install. Thanks Hans Werner Borchers
2012 Jan 27
3
Numerical instability in new R Windows development version
...xample runs fine on Debian Linux and Mac OS X 32-/64-bit architectures. In my understanding the approach is correct and, as said above, often used in numerical applications. Can someone explain to me why this fails for the Windows 64-bit compiler and what I should use instead. Thanks. Hans Werner Borchers ABB Corporate Research
2016 Sep 09
3
Different results for tan(pi/2) and tanpi(1/2)
...tion > tan(pi*x) as x approaches 1/2 are different, +Inf and -Inf, so the limit is > not well defined. Hence the computer function tanpi(1/2) ought to return > Not-a-Number. > > Bill Dunlap > TIBCO Software > wdunlap tibco.com > > On Fri, Sep 9, 2016 at 10:24 AM, Hans W Borchers <hwborchers at gmail.com> > wrote: >> >> As the subject line says, we get different results for tan(pi/2) and >> tanpi(1/2), though this should not be the case: >> >> > tan(pi/2) >> [1] 1.633124e+16 >> >> > tanpi(1/2) >&g...
2013 Jul 16
2
Problem following an R bug fix to integrate()
...w/o good reason. If there is a connection to a bug fix to integrate(), with NEWS item "integrate() reverts to the pre-2.12.0 behaviour. (PR#15219)", then I do not understand what this pre-2.12.0 behavior really means. Thanks for any help or a hint to what shall be changed. Hans W Borchers PS: This kind of tricky definition in function 'fn' has caused some discussion on this list in July 2009. I still think it should be allowed to proceed in this way.
2004 Feb 02
2
Nearest Neighbor Algorithm in R -- again.
...erform this task using R functions? Even better, is there a free implementation of kd-trees that I could utilize (the one I found did not conform to the ANSI C standard)? Someome pointed to 'spdep' of the R-Sig-Geo project, but 'knearneigh' only accepts 2D data points. Hans Werner Borchers ABB Corporate Research, Germany ________________________________________________________________________ require (class) nearest <- function (X, n, k=3) ## Find k nearest neighbors of X[n, ] in the data frame ## or matrix X, utilizing function knn1 k-times. { N <- nrow(X) # inds co...
2009 Jul 07
3
r-project.org address blacklisted by anti-spam software
Dear List: An e-mail mentioning the r-project.org address and sent to a friend at a German university was considered spam by the local spam filter. Its reasoning: the URL "r-project.org" is blacklisted at uribl.swinog.ch resp. at antispam.imp.ch. I checked the list http://antispam.imp.ch/swinog-uri-rbl.txt [caution: long list] and indeed, there it was. Can anybody explain how or
2002 May 07
2
Discretization of numeric attributes
...MDL principle, the C4.5 approach, etc. I am especially interested in those methods that take a factor as goal target into account for discretizing continuous-valued attributes. Is there an implementation of any one of those methods available in the many libraries available for R ? Hans Werner Borchers ABB Corporate Research -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- 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 !) To:...
2016 Sep 09
3
Different results for tan(pi/2) and tanpi(1/2)
As the subject line says, we get different results for tan(pi/2) and tanpi(1/2), though this should not be the case: > tan(pi/2) [1] 1.633124e+16 > tanpi(1/2) [1] NaN Warning message: In tanpi(1/2) : NaNs produced By redefining tanpi with sinpi and cospi, we can get closer: > tanpi <- function(x) sinpi(x) / cospi(x) > tanpi(c(0, 1/2, 1, 3/2, 2))
2008 Sep 19
3
How to do knn regression?
Hello, I want to do regression or missing value imputation by knn. I searched r-help mailing list. This question was asked in 2005. ksmooth and loess were recommended. But my case is different. I have many predictors (p>20) and I really want try knn with a given k. ksmooth and loess use band width to define neighborhood size. This contrasts to knn's variable band width via fixing a
2023 Mar 31
1
Query: Could documentation include modernized references?
>>>>> Duncan Murdoch >>>>> on Sun, 26 Mar 2023 12:41:03 -0400 writes: > On 26/03/2023 11:54 a.m., J C Nash wrote: >> A tangential email discussion with Simon U. has >> highlighted a long-standing matter that some tools in the >> base R distribution are outdated, but that so many >> examples and other tools may use
2016 Sep 09
0
Different results for tan(pi/2) and tanpi(1/2)
...best estimate. Using finite precision approximations to irrational and other numbers that cannot be stored exactly can have all types of problems at and near certain values, that is why there are many specific functions for calculating in those regions. On Fri, Sep 9, 2016 at 12:55 PM, Hans W Borchers <hwborchers at gmail.com> wrote: > The same argument would hold for tan(pi/2). > I don't say the result 'NaN' is wrong, > but I thought, > tan(pi*x) and tanpi(x) should give the same result. > > Hans Werner > > > On Fri, Sep 9, 2016 at 8:44 PM, William D...
2008 Jun 26
1
Question about Constraint Optimization
Dear All, I am having trouble in using R function "constrOptim" to do constraint optimization. It seems that "constrOptim" calls function "optim" when it does the optimization, and "optim" allows us to set "method" to be "SANN" if we want to use simulated annealing. In "optim", the function allows us to set gradient to be
2012 Feb 16
3
ACM Software Copyright and License Agreement
ACM Software Copyright and License Agreement I have often seen the use of routines from the ACM Collected Algorithms, i.e. <netlib.org/toms/> (CALGO, or Trans. On Math. Software, TOMS), in Open Source programs, maybe also in some R packages --- and sometimes these programs are distributed under the GPL license, sometimes under proprietary licenses, e.g. in Scilab. The use of these CALGO
2008 Apr 01
2
Applying rbind() to a sequence of data frame names
I have a set of data frames ds1, ds2, ... each having the same columns and column names: ds1 <- data.frame(x=c(1,2,3,4), y=c(5,6,7,8)) ds1 <- data.frame(x=c(9,10,11,12), y=c(13,14,15,16)) ... and I would like to combine them into just one data frame like ds <- rbind(ds1, ds2, ...) Because there are so many of them, I will have to use a character array nms <-
2009 Dec 07
4
Subset sum problem.
Hi, I'm quite new to the R-project. I was suggested to look into it because I am trying to solve the "Subset sum" problem", which basically is: Given a set of integers and an integer s, does any non-empty subset sum to s? (See http://en.wikipedia.org/wiki/Subset_sum_problem) I have been searching the web for quite some time now (which is how I eventually discovered that my
2009 Aug 02
1
Inaccurate complex arithmetic of R (Matlab is accurate)
Dear All, Hans Borchers and I have been trying to compute "exact" derivatives in R using the idea of complex-step derivatives that Hans has proposed. This is a really, really cool idea. It gives "exact" derivatives with only a minimal effort (same as that involved in computing first-order forward-dif...
2010 Mar 21
2
Find a rectangle of maximal area
For an application in image processing -- using R for statistical purposes -- I need to solve the following task: Given n (e.g. n = 100 or 200) points in the unit square, more or less randomly distributed. Find a rectangle of maximal area within the square that does not contain any of these points in its interior. If a, b are height and width of the rectangel, other constraints may have to be
2012 Feb 10
3
Schwefel Function Optimization
All, I am looking for an optimization library that does well on something as chaotic as the Schwefel function: schwefel <- function(x) sum(-x * sin(sqrt(abs(x)))) With these guys, not much luck: > optim(c(1,1), schwefel)$value [1] -7.890603 > optim(c(1,1), schwefel, method="SANN", control=list(maxit=10000))$value [1] -28.02825 > optim(c(1,1), schwefel, lower=c(-500,-500),