similar to: Automatic differentiation in R

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

Hey, what is the R function for the mathematical limit ? e.g. to calculate and return the amount that the expression X^2 +X +2 approach as X approach 2 (X-> 2) 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 R People: Is there a package for automatic differentiation, please? thanks in advance, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at gmail.com

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, Could anyone tell me what is the command used in R to do 1. Differentiation 2. Newton Raphson method (Numerical Analysis in general...) Are there any packages separately for this? Thanks for your help! BR, Shubha [[alternative HTML version deleted]]

Hi all, I wrote a symbollic differentiation function in R, which can be downloaded here: http://www.econ.upenn.edu/~clausen/computing/Deriv.R http://www.econ.upenn.edu/~clausen/computing/Simplify.R It is just a prototype. Of course, R already contains two differentiation functions: D and deriv. However, these functions have several limitations. They can probably be fixed, but

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: >

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

Martin (see below) gives a good explanation of the difference between AD and symbolic differentiations. I'm of the opinion we can use both. However, the real issue as far as I'm concerned (from an optimizer's point of view, which may also be that of ODE and PDE folk) is that right now none of the offerings that we have are easy to use. Indeed, usability is one of the key issues in my

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

Dear Alberto, There are fisheries people also in Europe using AD Model Builder (Denmark and England for instance), but you are probably right that it is more widespread in North America. There is also effort going on where people try to make assessment models written in ADMB callable from R. best regards, hans > think AD Model Builder is mainly used for fisheries assessment in North

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

This may be a question to R-development but I'm not sure. Symbolic differentiation is implemented in R (maybe not for extremely complex expressions), but it proves that it can be done. I know that in C++ it can be done (symbolic c++), do you think in R it can be programmed just using the R language without resorting to external sources? Does anyone know or can estimate the amount of resources

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

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 =

I am using C code to create an S4 object based on Douglas Bates's example in his lecture notes on <http://www.ci.tuwien.ac.at/Conferences/DSC-2003/Tutorials/RExtensions/slide s.pdf> http://www.ci.tuwien.ac.at/Conferences/DSC-2003/Tutorials/RExtensions/slides .pdf e.g. SEXP La_DGE_dc(SEXP A) { SEXP aa = PROTECT(duplicate(A)); SEXP adims, pivot, val; int

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]

Hello, I would like to create a function that gets passed a class name and then calls setClass, and a few other functions, inside. I have done this in the past with setmethod, creating accessors for all slots in a set of S4 classes. But setClass is choking when my function is called isnide a package, telling about an error in exists(cname, where). I assume this to be a problem with the