similar to: limits

Hi, as I find problems with yacas package... is there any R function equivalent to the yacas function "Factor" ? the factor function which i found in the R help is not the same. it doesn't factor an algebraic expression...... thanks hassan [[alternative HTML version deleted]]

Hi, can anyone tell me if R can be used to rearrange very complicated equations in terms of one of the variables? I have: dx/dt = a*b*m*y*(1-x)-r*x and, having set: dy/dx = 0, need to rearrange in terms of x. The problem I have is that I don't know how to rearrange equations when the variables are not yet defined (I get messages warning me that x etc can't be found). I'm not sure

Hi I recently gave a presentation about Automatic Differentiation (AD) and R at the Eighth Euro AD Workshop in Oxford (17/07/09). The presentation was intended as a general introduction to R and the desire for a generic AD interface for R. During the presentation I emphasised the need and the high level of interest that the R community has in developing such an interface and that input from the

Las dos Enviado desde mi iPhone > El 28/11/2013, a las 18:07, "Carlos J. Gil Bellosta " <cgb en datanalytics.com> escribió: > > ¿Numérica o simbólicamente? > > Un saludo, > > Carlos J. Gil Bellosta > http://www.datanalytics.com > > El día 28 de noviembre de 2013 18:03, jmcontreras <jmcontreras en ugr.es> escribió: >> Hola a todos

I am experimenting with rSymPy, and it seems to work nice. However, I dislike the need to wrap all sympy expressions within quotes, it leads to ugly calls like library(rSymPy) Var("x,y,z") sympy("(x+y)**2") and so on. Inspired by the function cq from mvbutiles package: library(mvbutils) > cq function (...) { as.character(sapply(as.list(match.call(expand.dots =

In efforts to improve optimization tools for R, one of my interests has been getting automatic differentiation capabilities so that analytic rather than numerical derivatives can be used. They would be helpful in several other areas besides optimization, My timings show factors of the order of 1000s in time improvements by avoiding numerical derivatives in some cases. There has been some work in

I am working on a project that requires me to do very large factorial evaluations. On R the built in factorial function and the one I created both are not able to do factorials over 170. The first gives an error and mine return Inf. Is there a way to have R do these larger calculations (the calculator in accessories can do 10000 factorial and Maple can do even larger) -- View this message in

Dear R People: I have been experimenting with rPython, rSymPy, and rJython. Here is my latest snag: > library(rJython) Loading required package: rJava Loading required package: rjson > library(rSymPy) > rJython <- rJython() > x <- "x" > y <- "y" > rJython$exec("from sympy import *") Error in .jcall("RJavaTools",

Hi all, I'm having major difficulty using the rSymPy package this week, but I have used it without problems before now. Here is an example of what's happening: > library(rSymPy) Loading required package: rJava > sympy("var('a b c d')") Error in .jcheck() : No running detected. Maybe .jinit() would help. And I have no idea how to fix it. I Have tried re-installing

Hi, I'm wondering if someone has solved the problem of converting very large integers to hex. I know about format.hexmode and as.hexmode, but these rely on integers. The numbers I'm working with are overflowing and losing precision. Here's an example: x <- "6595137340052185552" # stored as character as.integer(x) # warning about inaccurate conversion

Hello yet again, R People: I was working with Ryacas and yacas last night and all was well. Now this morning, I keep getting the following: > a <- Sym("a") > a Error in summary.connection(x) : invalid connection > When I go to yacas from the command line, it works fine. Any suggestions, please? I'm thinking that a port might be open, but here I have: >

Cordial saludo quiero saber como calculo integrales impropias e indefinidas en R, y como calcular limites soy nuevo en R Muchas gracias Harvey Vargas "El verdadero perdedor no es aquél que no gana. El verdadero perdedor es aquél que tiene tanto miedo a no ganar que ni siquiera lo intenta". Alan Arkin [[alternative HTML version deleted]]

2009/8/30 Uwe Ligges <ligges at statistik.tu-dortmund.de>: [snip] > Guido van Steen wrote: [snip] >> Something that interests me too: What about R's policy with respect to >> including binary files? I saw that developers should include a file [snip] > Please do not include binary files and carefully watch for licenses of those > files (e.g. if GPL'ed, you need to

Hi there, I have created the function below: pirate<-function(x){ a<-x-1; b<-a/5; c<-a-b; d<-c-1; e<-d/5; f<-d-e; g<-f-1; h<-g/5; i<-g-h; j<-i-1; k<-j/5; l<-j-k; m<-l-1; n<-m/5; o<-m-n; final<-o/5; final } I want to run this function until the output ('final') is an exact integer (e.g. 893.00000 rather than 893.78332). I then need to

Hi! I have a table representing both absolute and relative frequency, for example (code to get example data under the signature): Italy Germany absolute 100 105 relative 40.51 41.18 How can I print a different number of decimal digits? I try to transform to as.character, but cells result aligned to left and I don't like this solution. At the

Hi! I need to import in R some SAS dataset (sas7bdat). I found two functions to do it: "read.ssd" from the package "foreign" and "sas.get" from "Hmisc". df = read.ssd(libname = path2data, sectionnames = "sasSmallDataset", tmpXport = path2data, tmpProgLoc = path2data, sascmd = path2sas) sas.get(libraryName = path2data, member =

Dear R users, I have been using rsympy to solve a set of simultaneous equations from R. There are two solutions for the variable I'm interested in, xx[0] and xx[1], which are in terms of symbols called lam and conc. I'd like to pick out the one which is positive at (lam=0, conc=0) and call it mysol. In python I could write: if (xx[0].subs(lam,0)).subs(conc,0)>0: mysol=xx[0]

I am trying to construct a two-way table where, instead of printing the two-way frequencies in the table, I would like to print the values of a third variable that correspond to the frequencies. For example, the following is easily constructed in R > fact1 <- factor(sample(LETTERS[1:3],10,replace=TRUE)) > fact2 <- factor(sample(LETTERS[25:26],10,replace=TRUE)) > fact3

Dear all, I'm working with a model to estimate components of variance by using the lme() function. The model is as the following: model=lme(fixed=X~1+as.factor(station),data=myData,na.action=na.exclude,rand om=~N+1|spliceOrHoming) Where X is the response measured variable, station is treated as fixed effects factor, N is a continuous variable, and spliceOrHoming is a (ordered)

Dear R Users: I would like to use symbolic integration from rSymPy and pass in the actual function. So I have > sympy("x=Symbol('x')") and if I use > sympy("integrate(cos(x),x)") it works fine. But what I want to do is something like > y <- "cos(x)" > sympy("integrate(y,x)") "cos(x)*x" Has anyone run into this, please?