similar to: Automatic Differentiation for 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

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

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]]

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 =

Ryacas is now available on CRAN. (Previously it was available on the Omegahat repository.) Ryacas is an R package that provides an interface from R to the yacas computer algebra system. It can be used for computer algebra, exact arithmetic, ASCII pretty printing and R to TeX output. R, yacas and Ryacas are all free software packages distributed under the GPL version 2. Ryacas is written in R.

Ryacas is now available on CRAN. (Previously it was available on the Omegahat repository.) Ryacas is an R package that provides an interface from R to the yacas computer algebra system. It can be used for computer algebra, exact arithmetic, ASCII pretty printing and R to TeX output. R, yacas and Ryacas are all free software packages distributed under the GPL version 2. Ryacas is written in R.

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: >

Ryacas is an R interface to the free yacas computer algebra system. Ryacas allows one to send R expressions, unprocessed yacas strings and certain other R objects to a separate yacas process from R and get back the result. It also has facilities for manipulating yacas strings and R expressions destined for yacas processing. It can be used for exact arithmetic, symbolic math, ASCII pretty

Ryacas is an R interface to the free yacas computer algebra system. Ryacas allows one to send R expressions, unprocessed yacas strings and certain other R objects to a separate yacas process from R and get back the result. It also has facilities for manipulating yacas strings and R expressions destined for yacas processing. It can be used for exact arithmetic, symbolic math, ASCII pretty

Ryacas is an R interface to the free yacas computer algebra system. Ryacas allows one to send R expressions, unprocessed yacas strings and certain other R objects to a separate yacas process from R and get back the result. It also has facilities for manipulating yacas strings and R expressions destined for yacas processing. It can be used for exact arithmetic, symbolic math, ASCII pretty

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",

I'm having trouble loading Ryacas. I've downloaded and extracted Ryacas 0.2-9 (also tried Ryacas ) and yacas 1.0.63, have the latest version of R and have tried the following (this works for installing other packages): install.packages("Ryacas") library(Ryacas) install.packages("yacas") library(yacas) and get this: Warning message: package ‘yacas’ is not available

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?

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 having issues with Ryacas errors. I searched and found this error was reported in 2006, but nothing since. > library(Ryacas) Loading required package: XML > yacas(expression(Factor(x^2-1))) [1] "Starting Yacas!" CommandLine(1) : Expecting ) closing bracket for sub-expression, but got ^ instead > yacas("D(x)Sin(x)") CommandLine(1) : Expecting ) closing bracket

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

Thanks for the response. Yes, I did study the vignette but did not understand it fully. Anyway, I have tried once again now. I am happy to say that I have got what I wanted. library(Ryacas) x <- Sym("x");U <- Sym("U");x0 <- Sym("x0");C <- Sym("C") my_func <- function(x,U,x0,C) { return (U/(1+exp(-(x-x0)/C)))} FirstDeriv <-

There is either something wrong with either me or is Yacas/Ryacas doing odd things. See below I ask to simpify an expression and the there's output! If this is a simplification.. well.. Do you think there is something set wrong somewhere. Thanks. > library(Ryacas) Loading required package: XML > a=Sym("a") > N=Sym("N") > b=Sym("b") >

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]]

Dear All I am doing the following: > x <- yacas("3/2") > for (i in 2:400) + x <- yacas(paste(x,"*",x)) > x expression(Inf^1.260864167e+117/Inf^6.304320836e+116) > Eval(x) [1] NaN No luck this way. However, I am successful with > y <- yacas("(3/2)^400") > y expression(7.05507910865533e+190/2.58224987808691e+120) > Eval(y) [1]