similar to: Ryacas and fractions with simultaenously very large numerators and denominators

On Wednesday 28 January 2009 11:32, Chris Lattner wrote: > On Jan 28, 2009, at 9:06 AM, David Greene wrote: > > On Tuesday 27 January 2009 18:28, Eli Friedman wrote: > >> You can use a no-op bitcast for scalars, but there isn't any reliable > >> way to do it for all first-class values. > > > > Guh. > > > >> That said, I don't quite

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

Hello, I have search on R website but do not find any solution. I would like to know if R has some functionalities to produce analytical results of equation. or more generally if it contains some functions to simplify equation. For example: I would like to obtain x1 from: x1+x2=8 (x1=8-x2) x1^2+x2=8 (x1=sqrt(8-x2)) Is is possible in R ? if not, do you know a (free) software that could do the

>From time to time people request symbolic computations beyond what D() and deriv() etc can provide. A brief look at the internet shows that there are many more or less developed computer algebra packages freely available. Therefore, I wondered if it would be an idea to try to 'integrate' one of these packages in R, which I guess can be done in more or less elegant ways... I do not know

Hi I am currently (for pedagogical purposes) writing a simple numerical analysis library in R. I have come unstuck when writing a simple Newton-Raphson implementation, that looks like this: f <- function(x) { 2*cos(x)^2 + 3*sin(x) + 0.5 } root <- newton(f, tol=0.0001, N=20, a=1) My issue is calculating the symbolic derivative of f() inside the newton() function. I cant seem to get R to

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: >

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

On Jan 28, 2009, at 9:50 AM, David Greene wrote: > How can a set of phis with a dependence execute simultaenously? > There is only one definition of x and it has to happen before the > use of > x in the phi defining y, doesn't it? > The "normal" answer would be that they execute atomically only at the IR level. Part of the out-of-SSA translation that happens in

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

Dear all, I want to equalize a symbolic derivative (of a function with two variables) with zero and convert it to a variable, e.g. x. I'm computing the derivative by: (found it in the archive) library(Ryacas) f <- function(x,y) (100-x-y)*x-10*x yacas(f) # register f with yacas Df <- f body(Df) <- yacas(expression(deriv(f(x,y),x)))[[1]] Df R-Output: function (x, y) 100 - x - y -

Dear List: Is any one aware of a package that would extend the D() function and allow for one to maximize a likelihood function symbolically? Something akin to Solve[x==0, parameter] function in Mathematica? Clearly R has the capacity to _compute_ MLEs given a set of data. But, I'm looking for a package that would allow for me to define the likelihood function, find the 1st order partial

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]]

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") >

On Jan 28, 2009, at 9:50 AM, David Greene wrote: >> Why is this a problem? All phis execute "atomically". What problem >> are you seeing in practice? > > I'm getting incorrect answers. > > How can a set of phis with a dependence execute simultaenously? > There is only one definition of x and it has to happen before the > use of > x in the phi

Hi all, I am trying to implement the following matlab code with Ryacas : syms U x x0 C d1=diff(U/(1+exp(-(x-x0)/C)),x); pretty(d1) d2=diff(U/(1+exp(-(x-x0)/C)),x,2); pretty(d2) solx2 = solve(d2 == 0, x, 'Real', true) pretty(solx2) slope2=subs(d1,solx2) I have tried the following : library(Ryacas) x <- Sym("x");U <- Sym("U");x0 <-

On Wednesday 28 January 2009 12:30, Chris Lattner wrote: > On Jan 28, 2009, at 9:50 AM, David Greene wrote: > >> Why is this a problem? All phis execute "atomically". What problem > >> are you seeing in practice? > > > > I'm getting incorrect answers. > > > > How can a set of phis with a dependence execute simultaenously? > > There

On Jan 28, 2009, at 9:06 AM, David Greene wrote: > On Tuesday 27 January 2009 18:28, Eli Friedman wrote: > >> You can use a no-op bitcast for scalars, but there isn't any reliable >> way to do it for all first-class values. > > Guh. > >> That said, I don't quite follow the issue. This is SSA, so the >> only way a >> value can change is if