Re: [R] non-linear integer optimization?

darckeen hotmail.com> writes: > > Are there any packages that do non-linear integer otimization? Looked at > lpSolve but i'm pretty sure it only works with linear programming and not > non-linear, tried "L-BFGS-B" optim after flooring all my params, works > somewhat but seems really inefficient

Re: [R] Prime Factorization

David Winsemius comcast.net> writes: > > A further citation that answers the question I raised (and > inaccurately predicted no value) regarding prime.sieve : > > http://finzi.psych.upenn.edu/R/Rhelp02/archive/49773.html > > This was found with Barons search facility set for rhelp postings:

Re: [R] bivariate vector numerical integration with infinite range

baptiste auguie googlemail.com> writes: > > Thanks. I am having trouble getting adaptIntegrate to work with a > multivalued integrand though, and cannot find a working example. > Anyone had better luck with it? The function to be integrated needs a vector as input: f <- function(x) {

Re: [R] Prime Factorization

David Winsemius comcast.net> writes: > > On Sep 21, 2010, at 11:33 AM, Cliff Clive wrote: > > > > > Hi everyone, I have a very quick question: > > > > Is there a ready-made function in R or any R packages to find the > > prime > > factorization of an integer? > > Yes. At least two. The obvio

Re: [R] bivariate vector numerical integration with infinite range

baptiste auguie googlemail.com> writes: > > Thanks, adaptIntegrate() seems perfectly suited, I'll just need to > figure a transformation rule for the infinite limit. The suggestion of > x->1/x does not seem to work here because it also transforms 0 into > -infinity. I think exp(pi* sinh(x)) coul

Re: [R] bivariate vector numerical integration with infinite range

baptiste auguie googlemail.com> writes: > > Dear list, > > I'm seeking some advice regarding a particular numerical integration I > wish to perform. > > The integrand f takes two real arguments x and y and returns a vector > of constant length N. The range of integration is [0, infty) for x an

Re: [R] optimized value worse than starting Value

Barry Rowlingson lancaster.ac.uk> writes: > > On Wed, Sep 8, 2010 at 1:35 PM, Michael Bernsteiner > hotmail.com> wrote: > > > > Dear all, > > > > I'm optimizing a relatively simple function. Using optimize the optimized > > parameter value is worse than the starting. why? I would like to stre

Re: [R] calculating area between plot lines

A. Marcia BARBOSA gmail.com> writes: > > Hi everyone. I have these data: > > probClass<-seq(0,0.9,0.1) > prob1<-c(0.0070,0.0911,0.1973,0.2949,0.3936,0.5030,0.5985,0.6869,0.7820,0.8822) > prob2<-c(0.0066,0.0791,0.2358,0.3478,0.3714,0.3860,0.6667,0.6400,0.7000,1.) > > # which I'm plotting as

Re: [R] Regarding naive baysian classifier in R

Vishnampettai yahoo.com> writes: > Hi, > I have a small doubt regarding naive Bayes. I am able to classify the > data's properly but i am just stuck up with how to get the probability > values for naive bayes. In the case of SVM we have "attr" function that > helps in displaying the probability

Re: [R] LSAP and the Hungarian algorithm [was: R-help]

Ravi Varadhan jhmi.edu> writes: > > However, The "clue" package has the solve_LSAP() function (as pointed out by > Hans Werner) that solves the linear sum assignment problem, but it uses the > Hungarian algorithm that was requested by you. > > The lp.assign() function in "lpSolve" package (as p

Re: [R] LSAP and the Hungarian algorithm [was: R-help]

venkatesh bandaru gmail.com> writes: > If you had searched for it, you would have easily found the 'clue' package: In package clue solve_LSAP() enables the user to solve the linear sum assignment problem (LSAP) using an efficient C implementation of the Hungarian algorithm. Hans We

Re: [R] Puzzle

Ben Holt bio.ku.dk> writes: > I have data similar to this: > > Location Surveyor Result > A1 83 > A2 76 > A3 45 > B1 71 > B4 67 > C2 23 > C5 12 > D3 34 > E4

Re: [R] Problem to compute a function with very large numbers

Nan Zhao student.ethz.ch> writes: > > Thank you Dennis for your explanations! > > The results you found are the same as mine. with first an infinity result, > followed by NaN. It seems that, when the number becomes too small, R must > round it up to 0. Hence I was wondering if there might a way

Re: [R] Games

Silvano uel.br> writes: > > Hi, > > I want to build the table of a football league with 11 > teams. All play together. So will 55 games. > Since there are an odd number of teams in each round a team > will not play. The easy solution is moving around a table with one team pausing. #

Re: [R] Why use numFold in evaluate_Weka_classifier of RWeka

s0300851 tp.edu.tw> writes: > > Hi everyone, > > I have a question about using RWeka package， > we know that instruction make_Weka_classifier that can help > us to build a model,and evaluate_Weka_classifier instruction > can help us to evaluate the performance of the model using on new data.

Re: [R] Optimization problem with nonlinear constraint

Uli Kleinwechter uni-hohenheim.de> writes: > > Dear Ravi, > > As I've already written to you, the problem indeed is to find a solution > to the transcendental equation y = x * T^(x-1), given y and T and the > optimization problem below only a workaround. I don't think optimization is the ri

Re: [R] Hurst Exponent Estimation

ar from others about experiences with financial times series. Best, Hans Werner > On 7/22/2010 12:25 AM, Hans W Borchers wrote: > > Lorenzo Isella gmail.com> writes: > >> Dear All, > >> I am a novice when it comes to time-series analysis and at the moment I

Re: [R] Hurst Exponent Estimation

Lorenzo Isella gmail.com> writes: > > 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. Some time ago I tested some of the classical chaotic time series (such as the logistic map an

Re: [R] Double Integration

Bogaso Christofer gmail.com> writes: > > Hi Ravi, your suggestion helped me as well a lot. If I look into > that function, I see this function is calling another function : > > .Call("doCubature", as.integer(fDim), body(f.check), > as.double(lowerLimit), as.double(upperLimit), >

Re: [R] Double Integration

Sarah Sanchez yahoo.com> writes: > > Dear R helpers > > I am working on the Bi-variate Normal distribution probabilities. > I need to double integrate the following function > (actually simplified form of bivariate normal distribution) > > f(x, y) = exp [ - 0.549451 * (x^2 + y^2 - 0.6 * x * y)

Re: [R] double integral

suman dhara gmail.com> writes: > > Sir, > I want to calculate double integral in R. Is there any function to do this? If your domain of integration is a hypercube, try packages 'cubature' or 'R2cuba'. Otherwise, you have to uncover more information about your specific problem and/or function.

Re: [R] logarithmic integrals in R?

ion. I am certain I 've seen them in AandS' handbook (where else?), but sure cannot remember in which chapter or page. Which logarithmic integrals do you really need, and on what range? Regards, Hans Werner > On Sat, May 29, 2010 at 01:15:29PM +, Hans W. Borchers wrote: > > Ol

Re: [R] logarithmic integrals in R?

Oliver Kullmann swansea.ac.uk> writes: > > Hello, > > I couldn't find information on whether the logarithmic integrals > > Li_m(x) = integral_0^x log(t)^(-m) dt > > for x >= 0 are available in R? I saw your request only this weekend. The first logarithmic integral can be computed using the e

Re: [R] best polynomial approximation

I guess you may be looking for the Remez algorithm. AFAIK there is no implementation in one of the R packages. You can find FORTRAN code in the Collected Algorithms of the ACM (no. 604) which probably could be called from R. There appears to exist a discrete, equi-distant(?) version as function '

Re: [R] Find a rectangle of maximal area

Barry Rowlingson lancaster.ac.uk> writes: > > On Mon, Mar 22, 2010 at 4:28 PM, Hans W Borchers > googlemail.com> wrote: > > > Still I believe that a clever approach might be possible avoiding the need > > to > > call a commercial solver. I am getting

Re: [R] Find a rectangle of maximal area

Hans W Borchers googlemail.com> writes: > > 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 rect

[R] 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

Re: [R] Sorting

David Neu davidneu.com> writes: > David Neu davidneu.com> writes: > > Hi, > > I have a list of vectors (of varying lengths).  I'd like to sort this > list by applying a function to each pair of vectors in the list and > returning information to sorting routine that let's it know which one > is l

Re: [R] Sorting

David Neu davidneu.com> writes: > > Hi, > > I have a list of vectors (of varying lengths). I'd like to sort this > list by applying a function to each pair of vectors in the list and > returning information to sorting routine that let's it know which one > is larger. > > To solve problems lik

Re: [R] Solving an optimization problem: selecting an " optimal" subset

Erwin Kalvelagen-2 wrote: > > Hans W Borchers googlemail.com> writes: >> # Prepare inputs for MILP solver >> obj <- c(rep(0, n), 0, 1, 1, 0) >> typ <- c(rep("B", n), "B", "C", "C", "B") >>

Re: [R] Solving an optimization problem: selecting an "optimal" subset

Dimitri Shvorob gmail.com> writes: > > Given vector of numbers x, I wish to select an n-subset with sum closest > fixed value s. Can anyone advise me how to approach this, in R? > > I have considered Rcplex package, which handles integer/binary > linear/quadratic optimization problems, but have d

Re: [R] Solving an optimization problem: selecting an "optimal" subset

Dimitri Shvorob wrote: > > Same request to Hans: > I am afraid I need a little more spoon-feeding following > >> I sent a GAMS script modeling this problem to the NEOS solvers > > Thanks a lot! > If you have access to CPLEX (I mean the commercial program, not Rcplex which is just an interfa

Re: [R] Solving an optimization problem: selecting an "optimal" subset

Dimitri Shvorob gmail.com> writes: > > > This is a "subset sum" problem and has been discussed here in December > > Thanks a lot! Will investigate. > > > Can you settle for an approximate solution? > > Absolutely. You can use the script from the thread "subset sum problem" to find approxima

Re: [R] Solving an optimization problem: selecting an & quot;optimal" subset

Dimitri Shvorob gmail.com> writes: > > > Is it a subset of a vector containing 100 elements, or 1ths? > > I need to pick 2-40 elements out of a 50-200-element-long vector. > > > A random number of elements that should be chosen, or the best 10 values > > which sums up to a defined value?

Re: [R] problem with the precision of numbers

kayj yahoo.com> writes: > > > Hi All, > > thank you all for your help. I have tried Bill's script and it works! so I > am trying to think what was the problem and it looks like it i sthe > precision. so you defined a function of the precision and evaluates at > precision=500. Bill, I was wonder

Re: [R] problem with the precision of numbers

manchester.ac.uk> writes: > [...] > > I suspect this is an invented computation -- the "3456" strikes > me as "unlikely" (it reminds me of my habitual illustrative use > of set.seed(54321)). > > There is a definite problem with the development given by kayj. > When k=2000 and i=k, the formula

Re: [R] optimization problem

Ravi Varadhan jhmi.edu> writes: > > Dear Hans, > > I agree with your comments. My intuition was that the quadratic > form would be better behaved than the radical form (less > nonlinear!?). So, I was "hoping" to see a change in behavior when > the cost function was altered from a radical (i.

Re: [R] optimization problem

Ravi Varadhan jhmi.edu> writes: > > Interesting! > > Now, if I change the "cost matrix", D, in the LSAP formulation slightly > such that it is quadratic, it finds the best solution to your example: Dear Ravi, I thought your solution is ingenious, but after the discussion with Erwin Kalvela

Re: [R] how to count the total number of (INCLUDING overl apping) occurrences of a substring within a string ?

Hans W Borchers googlemail.com> writes: > Sorry, my fault. I forgot the brackets. With gregexpr("(.)(?=.\\1)", "ababacababab", perl = TRUE) it works as you suggested. Thanks Hans Werner __ R-help@r-project.org mailing

Re: [R] how to count the total number of (INCLUDING overl apping) occurrences of a substring within a string ?

I am still not able to reproduce this with lookahead. Attempts with gregexpr("(.)?=.\\1", "ababacababab", perl = TRUE) do not work as the lookahead expression apparently does not know about the captured group from before. Regards Hans Werner Correction: I meant the '

Re: [R] how to count the total number of (INCLUDING overl apping) occurrences of a substring within a string ?

Gabor Grothendieck gmail.com> writes: > > Use a zero lookaround expression. It will not consume its match. See ?regexp > > > gregexpr("a(?=a)", "aaa", perl = TRUE) > [[1]] > [1] 1 2 > attr(,"match.length") > [1] 1 1 I wonder how you would count the number of occurrences of, for example, 'aba'

Re: [R] Subset sum problem.

Geert Janssens telenet.be> writes: > > On Wednesday 9 December 2009, Hans W Borchers wrote: > > Geert Janssens telenet.be> writes: > > > [ ... ] > > > Has anybody tackled this issue before in R ? If so, I would be very > > > grateful if you cou

Re: [R] Subset sum problem.

Geert Janssens telenet.be> writes: > > 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.wikipedi

Re: [R] Modula Generators

Sam K yahoo.co.uk> writes: > > Hi all, > > Is there function on R for calculating Modula generators? For example for > primes above 100, e.g 157, i want > to know which number generates the group under multiplication mod 157. i.e i > want to find an element whose > order is 156. The problem I

Re: [R] Solve linear program without objective function

Andreas Wittmann gmx.de> writes: > > Dear R-users, > > i try to solve to following linear programm in R > > 0 * x_1 + 2/3 * x_2 + 1/3 * x_3 + 1/3 * x_4 = 0.3 > x_1 + x_2 + x_3 + x_4 = 1 > x_1, x_2, x_3, x_4 > 0, > x_1, x_2, x_3, x_4 < 1 > > as you can see i have no objective function here bes

Re: [R] Modular inverses

SJ Robson-Davis bristol.ac.uk> writes: > > I want to find the inverse of an integer k mod p (prime.) Is there a > function that can do this for me? I know i could simply write (k^(p-2)) %% > p, but i need to do this for large primes (above 100) and this gives the > warning message: > probabl

Re: [R] optim or nlminb for minimization, which to believe?

Your function named 'gradient' is not the correct gradient. Take as an example the following point x0, very near to the true minimum, x0 <- c(-0.2517964, 0.4898680, -0.2517962, 0.4898681, 0.7500995) then you get > gradient(x0) [1] -0.0372110470 0.0001816991 -0.0372102284 0.000182

Re: [R] Implementation of the "Shuffled Complex Evolution" (SCE-UA) Algorithm

Simon Seibert mytum.de> writes: > > Good evening list, > I'm looking for an R implementation of the "Shuffled Complex > Evolution” (SCE-UA) algorithm after Duan et al. (1993). Does anybody > know if there is an extension/ package existing that contains it? > Thanks very much for your help! Che

Re: [R] help using R's linprog for LP

Medha Atre gmail.com> writes: > > Hi, > > I found the reason. By default it puts a condition for x >= 0. Is > there a way to get rid of this condition? The constraints x >= 0 are used in most linear programming realizations. Some bounds from below are needed. The trick to circumvent the restr

Re: [R] Ubuntu, Revolutions, R

I updated to Ubuntu 9.10 Beta yesterday, and yes I do see the same message and I am a bit irritated. I don't want to read these 'marketing' lines any time I start up R. I simply deleted the lines from "/etc/R/Rprofile.site" for now, but I am still wondering who put that in. Is there any deeper r

Re: [R] Semi continous variable- define bounds using lpsolve

But of course, it is always possible to emulate a semi-continuous variable by introducing a binary variable and use some "big-M" trick. That is, with a new binary variable b we add the following two conditions: x3 - 3.6 * b >= 0 and x3 - 10 * b <= 0 # Big-M trick, here M >= 10

Re: [R] Semi continous variable- define bounds using lpsolve

I played around a bit with the original 'lp-solve' program --- i.e., not the R package but the program to be downloaded from Sourceforge ---, at least version 5.5.0.15 through its IDE. I was not even able to reproduce the example on semi-continuous variables in the reference documentation at

Re: [R] Quadratic Constraints

The package lpSolve (that I have recommended before) supports so-called 'semi-continuous variables', that is "Semi-continuous variables are variables that must take a value between their their minimum and maximum or zero. So these variables are treated the same as regular variables, e

Re: [R] Linear objective function with Quadratic constraints

vikrant S wrote: > > I am new to R and I want to solve this following problem using R. > > My Objective function is a linear function with Quadratic constraints. I > want to know how to solve this problem and which package will be helpful > for me for solving such type of problems. Moreover my

Re: [R] re ading jpeg images?

I found the 'biOps' package for "Image and data analysis" quite helpful. (I did some astronomical investigations with it --- counting galaxies in a Hubble picture---and I do recommend this package.) Under Windows you have to unpack the 'libjpeg' and 'libtiff' libraries beforehand somewhere in yo

Re: [R] computing the radius of an arc

Nair, Murlidharan T iusb.edu> writes: > > Alex Brenning, the developer of the RSAGA package told me that and I quote > "the RSAGA package (which uses functions from the free geographical > information system [GIS] SAGA GIS) has a curvature function that is designed > to calculate the curvatur

Re: [R] computing the radius of an arc

Nair, Murlidharan T iusb.edu> writes: > > Hi!! > > I am interesting in computing the radius of an arc that best approximates > a curve. Is there an R function that I can use to draw an arc? > Nothing useful came up when I searched help.search. Does anyone have any > suggestion to do this? >

Re: [R] Automatic differentiation in R

Having given a lecture on "Numerical Derivatives" just a short time ago, I would like to mention the following: Many functions, especially in engineering, are not available as formulas built simply from arithmetical operators and elementary functions. They are provided as intricate procedures, a

[R] R interface to PSwarm

Dear list: Being a bit unsatisfied with global optimization approaches in R such as "SANN" (in 'optim') or DEoptim, I looked for alternatives on the Web, such as PSwarm or PIKAIA. There is an R interface to PSwarm (version 1.4) on its home page which I wa

[R] 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/swi

Re: [R] R- NLP on R but ....

Rahul Varshney gmail.com> writes: > > I'll appreciate the help on the following problem: > > I solved many Nonlinear programming problems with nonlinear > constraintsRdonlp is working well but i am unable to get INTEGER data > with nonlinear constraints in Rdonlp. Is it possible to get Inte

Re: [R] Equivalent to Matlab's "Ans"

There is a discussion on this topic under the heading "A shorter version of .Last.value" on July 7, 2008, see for example http://www.nabble.com/A-shorter-version-of-%22.Last.value%22--to18322831.html#a18322831 --Hans Werner Stephane-18 wrote: > > Hi everyone, > I was just wondering if there i

Re: [R] Optimization and Linear Programming in R

csiro.au> writes: > Dear List, > > [...] > > We are looking for a solver that can deal with this nonlinear integer > programming problem. We looked at a number of packages on the CRAN Task > View: Optimization and Mathematical Programming, however, we have not > been able to locate one that

Re: [R] newtons method

Dear Ravi: Thanks for pointing out the homotopy methods. Coming from Mathematics I was always considering SINGULAR for such a task which is also providing results when the solution set is not isolated points, but an algebraic variety. For single points, homotopy methods appear to be an effectiv

Re: [R] MDL - Fayyad & Irani Discretization

I have asked for this some years ago and did not got a positive hint. To my knowledge this has not changed since then. Brian Ripley proposed to use the 'rpart' algorithm for discretization. I think I applied the RELIEF-F method at that time and also wrote a simplified Fayyad-Irani function on my

Re: [R] Constrined dependent optimization.

uch preprocessing is not worth doing and will not speed up the optimization procedure considerably. Regards, Hans Werner rkevinburton wrote: > > > It has been suggested that I do a cluster analysis. Wouldn't this bet > mepart way there? > > Thank you for your resp

Re: [R] Constrined dependent optimization.

Just in case you are still interested in theoretical aspects: In combinatorial optimization, the problem you describe is known as the Quadratic (Sum) Assignment Problem (QAP or QSAP) and is well known to arise in facility and warehouse layouts. The task itself is considered hard, comparable to th

Re: [R] Constrined dependent optimization.

Image you want to minimize the following linear function f <- function(x) sum( c(1:50, 50:1) * x / (50*51) ) on the set of all permutations of the numbers 1,..., 100. I wonder how will you do that with lpSolve? I would simply order the coefficients and then sort the numbers 1,...,100 accord

Re: [R] asking advice for Integer Programming packages

Looking into the 'Optimization' task view you will also identify the Rsymphony package. A short overview of these packages and a benchmark based on a test suite can be found in . Different problems may have quite different ru

Re: [R] Rdonlp2 -Query

Leo Guelman gmail.com> writes: > > Hi, > > Did anyone used this package? Could you please share your thought on it? What do you, exactly, mean with "share your thought on it"? It has its pros and cons, as always. Sure Rdonlp2 has been used, and it has been requested and discussed several time

Re: [R] R - MATLAB apply like function

ARDIA David unifr.ch> writes: > > Dear all, > I very often use the R function "apply", for speedup purposes. I am now also > using MATLAB, and would like to use the same kind of function. > I have already asked MATLAB people, and the answer is : "vectorize"... but of > course, this is not alwa

Re: [R] Self-Organizing Map analysis

glaporta freeweb.org> writes: > > Dear list, > I read the SOM package manual but I don't understand how to perform (for > example) 1) the SOM analysis on Iris data 2) with a visualization similar to > that of figure 7 in > http://www.cis.hut.fi/projects/somtoolbox/package/papers/techrep.pdf In

Re: [R] Subset Regression Package

Alex Roy gmail.com> writes: > > Dear all , > Is there any subset regression (subset selection > regression) package in R other than "leaps"? Lars and Lasso are other 'subset selection' methods, see the corresponding packages 'lars' and 'lasso2' and its description in The Elem

Re: [R] Outlier Detection for timeseries

Pele yahoo.com> writes: > > > Hello R users, > > Can someone tell if there is a package in R that can do outlier detection > that give outputs simiilar to what I got from SAS below. > > Many thanks in advance for any help! I guess you are talking about the OUTLIER procedure in SAS that att

Re: [R] general inverse solver?

Gabor Grothendieck gmail.com> writes: > > I am not sure what the point of all this is. The point of all this is: 1. Some users of R here on the list apparently would like to have more powerful CAS functionalities than Yacas can provide. 2. Many of the solution hints to Ryacas on this list w

Re: [R] general inverse solver?

a module could be very valuable for extending and improving the R system. Hans W. Borchers > That being said, without taking away from yacas there is work going on to > interface R to a second CAS. > > On Tue, Feb 10, 2009 at 2:33 AM, Hans W. Borchers > googlemail.com> wr

Re: [R] general inverse solver?

integrated Maxima into its numerical environment in a way that is really useful for numerical and symbolic computations. I could imagine that in a similar way Maxima can be integrated into R bringing the full power of computer algebra to the R community. Hans W. Borchers ABB Corporate Research

Re: [R] Event sequence analysis

Hans Werner Borchers Le 2 févr. 09 à 13:31, Hans W. Borchers a écrit : Dear R help, I am analyzing sequences of events described by time and a unique event tag. And I am searching for recurring patterns where patterns have to show up in a certain time window, e.g. 5 or 10 minute

[R] Event sequence analysis

Dear R help, I am analyzing sequences of events described by time and a unique event tag. And I am searching for recurring patterns where patterns have to show up in a certain time window, e.g. 5 or 10 minutes. Of course, inbetween these events other events may occur. I have applied basket analys

Re: [R] How to get solution of following polynomial?

RON70 yahoo.com> writes: > > > Hi Ravi, Thanks for this reply. However I could not understand meaning of > "vectorizing the function". Can you please be little bit elaborate on that? > Secondly the package "polynomial" is not available in CRAN it seems. What is > the alternate package? > > Tha

Re: [R] Execution of a .sce file through R

ykank gmail.com> writes: > > > Dear R Users > > Does some has any idea about how to execute a scilab file(.sce file) from > the Terminal in R. > Any kind of guidance would be highly welcomed and appreciated. Have you looked into your Scilab directory? In mine -- under Windows XP and Scila

Re: [R] getting ISO week

Gabor Grothendieck gmail.com> writes: > > According to the definition in ?strptime (which is not the same as the > ISO definition): > > format(x, "%W") returns > > "Week of the year as decimal number (00–53) using Monday as the first > day of week (and typically with the first Monday of the ye

Re: [R] getting ISO week

Gabor Grothendieck gmail.com> writes: > > format(d, "%U") and format(d, "%W") give week numbers using > different conventions. See ?strptime Gabor, the results of format(aDate, "W") appear to be incorrect anyway, see: format(as.Date("2008-01-01"), "%W") #-> "00" There is never a wee

Re: [R] Pre-model Variable Reduction

Harsh gmail.com> writes: > > Hello All, > I am trying to carry out variable reduction. I do not have information > about the dependent variable, and have only the X variables as it > were. > ... > I looked for other R packages that allow me to do variable reduction > without considering a depend

Re: [R] How to solve following equation?

> I need to solve a equation like this : > > a = b/(1+x) + c/(1+x)^2 + d/(1+x)^3 > > where a,b,c,d are known constant. Is there any R-way to do that? Multiplying this expression with (1+x)^3 leads to a polynomial equation. I would certainly recommend the 'PolynomF' package here: # instal

Re: [R] optimization problem

Why not use one of the global optimizers in R, for instance 'DEoptim', and then apply optim() to find the last six decimals? I am relatively sure that the Differential Evolution operator has a better chance to come near a global optimum than a loop over optim(), though 'DEoptim' may be a bit slow

Re: [R] Examples of advanced data visualization

Tom Backer Johnsen psych.uib.no> writes: > [...] > The question is interesting, but what I have a somewhat negative > reaction to is the next passage: > > > > Please answer to my e-mail address. In case enough interesting material > > comes up, I will enter a summary here. > > It is nice that

[R] Examples of advanced data visualization

Dear R-help, I am looking for ideas and presentations of new and advanced data visualization methods. As an example of what I am searching for, the 'Many Eyes' pages at http://manyeyes.alphaworks.ibm.com/manyeyes/ may provide a good paradigm. I would be interested even if it will not be easy

Re: [R] Which data structure in R can mimic hash in PERL best?

> Dear all, > >Which data structure in R can mimic hash in PERL? I'd like to set > up a lookup table, which could be accomplished by HASH if using PERL. > Which of the data structures in R is the most efficient for lookup > table? > Thanks for your help. > > Best regards, > Leon The regular

Re: [R] strsplit (regex)

stephen sefick gmail.com> writes: > > #how do I break these up into first two letters (RM), number, and then > the last part > #is there an easily accessible regex tutorial on the internet? For regular expressions, the perl man pages at are quite good and

Re: [R] ttda and text-mining

LE PAPE Gilles neuf.fr> writes: > > The "ttda" package was devoted to text-mining. It seems to be no more > available. Did the name change ? Are other packages devoted to text-mining? The 'ttda' package is deprecated as is noted on the Task View "Natural Language Processing". The old code is st

Re: [R] How to do knn regression?

> This is a summary of discussions between Shengqiao Li and me, > entered here as a reference for future requests on knn regression > or missing value imputation based on a nearest neighbor approach. There several functions that can be used for 'nearest neighbor' classification such as knn, knn1 (

Re: [R] How to find a shift between two curves or data sets

Dear Sébastien, identifying similarity in curves or time series is one of the main tasks in the quite recent field of 'Functional Data analysis' (FDA). See the 2005 book by Silverman from Springer Verlag or the corresponding Web page at url{http://www.psych.mcgill.ca/misc/fda/}. The 'fda' pac

Re: [R] How to do knn regression?

Shengqiao Li stat.wvu.edu> writes: > > 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

Re: [R] Convex optimization in R?

Hesen Peng gmail.com> writes: > > Hi my R buddies, > > I'm trying to solve a specific group of convex optimization in R. The > admissible region is the inside and surface of a multi-dimensional > eclipse area and the goal function is the sum of absolution values of > the variables. Could any on

Re: [R] nonlinear constrained optimization

Paul Smith gmail.com> writes: > > Up to my best knowledge, R cannot deal with optimization problems with > nonlinear constraints, unless one uses the penalty method. Outside R, > Ipopt and Algencan can solve problems like yours, but one needs to > program in AMPL and/or C/Fortran. > > Paul > P

Re: [R] Exponential smoothing?

Öhagen Patrik mpa.se> writes: > > Dear List, > > I have used all my resources (i.e. "help.search) and I still havn't been > able to figure out if there is an Exponential Smoothing command in R. A few weeks ago the book "Forecasting with Exponential Smoothing" by Hyndman et al. has appeared

Re: [R] exporting adaBoost model

One way to port these kinds of models between applications is the Predictive Model Markup Language (PMML). The R package 'PMML' supports linear regression, rpart, SVM, and others, not adaBoost. On the other side, not even the Python machine learning library Orange does have an import function fo

Re: [R] FastICA

I may not have been as wrong as Prof. Ripley suggested when I wrote "The fastICA packages for Matlab and R (...) have a common origin at the Helsinki University of Technology." Please consider the following lines from the 'fastICA' help page (?fastICA): FastICA algorithm Description:

Re: [R] FastICA

Prof Brian Ripley stats.ox.ac.uk> writes: > > On Tue, 12 Aug 2008, someone with no signature wrote: > > > Maura E Monville gmail.com> writes: > > > >> > >> Is the FastICA R implementation as good as the MatLab Implementation ? > >> I would appreciate talking to someone who has used FastICA for

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