similar to: general inverse solver?

Just thought I'd ask. For those who've never seen TK!Solver, I strongly recommend taking a look. So far as I can tell, it's the only product of its type available, retail or open source, for any platform. What makes TK!Solver so cool is that it adaptively back-solves pretty much any unknown from any set of equations you give it. (or vector full of unknowns, producing a vector of

Hello again. Now I have the following: > xx [1] "Solve(1 - R/100==(2*y)/10000,R)" > yacas(xx) expression(list(R == 100 * (1 - 2 * y/10000))) > I would like to put in a value for y and obtain R. I've tried more stuff with eval and Eval, but no luck yet. Any suggestions would be much appreciated. Thanks, Erin -- Erin Hodgess Associate Professor Department of Computer

Hi, To my knowledge, Ryacas can do symbolic computation in R, like Mathematica or Maple. I wonder if it (or any other R package) can solve symbolically a system of equations? I have a system of four equations in four variables (non-linear, but not very hard to solve) and wonder if Ryacas or any other package can do it. I do not find the solution in Ryacas. Can it find a symbolic solution

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 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]

People, I'm researching some Bayesian statistic topics and in the midle of my study i found a very simple problem and i'm trying to find a simple package to solve this type of equations: Lets say that i need to compute beta values for the beta distribution and i now for example: E(teta)=a/(a+b) = 0,5 Var(teta)=ab/((a+b)^2(a+b+1))=0.05 So if i want to solve this to non-linear system 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

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 all: I'm looking for a package that similar to solver in MS. All I need is find a r to satisfy R0=sum( r * Xt ), where t are from 1 to n and Xt are come from another formula. The most package I found were to max or min the obj. function. Is there any package can do it? Thanks. Peter [[alternative HTML version deleted]]

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, for my diploma thesis I need to program a solver for Merton?s respectively Black?s and Scholes? Option pricing formula, which should be achieved for several dates. What I want to do is to estimate the value of a firm?s assets "vA" (x[2] denotes vA) and the option-implied volatility of firm?s assets "sigA" (x[1] denotes sigA) by solving it simultaneous using the Black

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 <-

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 <-

Greetings I'm a total newbie in R and I'm trying to make a comparisson of Excel and R in the fields of: - optimisation modeling (using solver) - decision trees - simulation modeling as described in Winston, Wayne L.: Practical Management Science. for optimisation modeling in Excel I would normaly use solver. In R however I can't seem to be able to find the solution. I've

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") >

Hi all, Earlier today I posted this question on s-news, so apologies to some for the duplication. > Please put aside your snobbery about Microsoft products for a moment. > > I am fitting population models to annual survey data for trout. For those of you familiar with ecological models, I am working in the Lefkovitch matrix framework; for those unfamiliar with that shorthand, the

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