similar to: How to do a target value search analogous to Excel Solver

Dear R-Help, I am trying to use R to solve a nonlinear equation many times for different values. I am looking for a mathematical nonlinear equation solution which may not have a closed solution form. For example, I have equation: 2 = (t^2)/log(t) What is t? I am wondering how to solve it in R. Many thanks, Zhu Wang Statistical Science Department SMU.

Dear all, i have daily stock prices for more than 10 years and want to compute annual volatilities for certain dates during this period. Since i have found no "easy" way to work with time data, the data presents itself in the structure TIme Index - Stock Price 1 - 15,6 2 - 17 ... ... 2010 - 28 2011- 28,5 ... 4500 - 23 Since I want to have the volatility only for certain dates, I

I can't for the life of me figure out how to get the roots for this simple (but sovable only iteratively) equation in R: x = z*(1-(1-2/z)^y where x and y are known, and z is unknown. In Matlab, this amounts to: [my.solution] = solve('x = z*(1-(1-2/z)^y') my.solution.real = solution(y-1,y) % bottom line displays non-imaginary solution (last element) Obviously, I'm deeply

Greetings all, I'm trying to figure out how to calculate the inverse CDF (i.e. a quantile) for a non-central F distribution. I could put together a quick numerical solver routine using the CDF, but I wonder if there's a function that I've missed that would be more efficient? Thank-you, Andrew Andrew Robinson Ph: 208 885 7115 Department of Forest Resources Fa: 208 885

Hello, I want to find the roots of an equation in two variables. I am aware of the uniroot function, which can do this for a function with a single variable (as I understand it...) but cannot find a function that does this for an equation with more than one variable. I am looking for something implementing similar to a Newton-Raphson algorithm. Thanks. -- Bill Shipley North American Editor for

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

Dear friends - I have a function for the charge in a fluid (water) buffered with HEPES and otherwise only containing Na and Cl so that [Na] - [Cl] = SID (strong ion difference) goes from -1 mM to 1 mM. With known SID and total HEPES concentration I can calculate accurately the pH if I know 3 pK values for HEPES by finding the single root with uniroot Now, the problem is that there is some

Just wondering if there's an R package which does tricks similar to what TK!Solver does. TK!Solver, for those not lucky enough to have found it, basically allows one to define a bunch of equations, assign values to an arbitrary subset of the variables, from which it calculates (either directly when possible or back-solving when not) the values of the other variable(s). thanks Carl

Esteemed colleagues I wonder if there is a package in R that performs the functions of the Excel SOLVER. Thanks in advance for the reply. Best regards, ------------------------- Estimados colegas Me pregunto si hay un paquete en R que funcione como el SOLVER de Excel. De antemano gracias por la respuesta. Saludos, -- Ricardo Bandin Llanos rbandin@udec.cl [c] Magíster Cs. m. Pesquerías

Hi, I can't seem to get any Excel Add-Ins to work. In particular, I need the 'Solver' for an assignment ... I've tried with two office versions (2007/2003), which I've managed to install successfully (you have to enable the Solver add-in during installation), but it's the same every time. When I try to start it up I get a message saying can't access SOLVER.XLA, and

Dear guys, I've put the puzzle solver running on LLVM 2.1. Well, at least partially, for it is failing three of SPEC2000 benchmarks. I will try to debug it now. The results are not as good as before. I mean, the puzzle solver is still the same, but the default allocator is producing very good code now. Even though, the puzzle solver produces faster code for half the benchmarks. It

This is applicable to either using optim or the differential equation solver or any similar solver Suppose I want to use the differential equation solver and this is my code d<-y[2] vdpol<-function(t,y) { list(c(1, d, 3, 4 ) } stiff<-ode(y=rep(0,4),times=c(0,1),func=dvdpol,parms=1) The thing is I want d to be composed of one of state variables in the

hi.. i used R a few days.. who can call me? same function solver in excel. _________________________________________________________________ [[elided Hotmail spam]] [[alternative HTML version deleted]]

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'm Pina and I'm a student in geology. I'm working with spectral profile of sand and I have to find the similarity between one spectral profile selected by hyperspectral image anche one that I created to mix different percentage of 4 mineral component. I have to find the best mix of percentage of this 4 mineral in order to have the best likeness with the spectral profile chose by

Hello -- The question I have is about the gmm() function from the 'gmm' package (v. 1.4-5). The manual accompanying the package says that the gmm() function is programmed to use either of four numerical solvers -- optim, optimize, constrOptim, or nlminb -- for the minimization of the GMM objective function. I wonder whether there is a way to pass controls to a solver used while calling

I am trying to use the package ode and periodically it will come up with this error message Warning..Internal T (=R1) and H (=R2) are such that in the machine, T + H = T on the next step (H = step size). Solver will continue anyway. And then the program just take very long to run. Is there anyway to get the program to terminate when this warning is issued instead of continuing to run ?

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

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

Dear All, I was using rk4 and lsoda to solve a ODE system. However, both of them gave bad accurate solutions, especially compared with Matlab solver ODE45. For example, ODE45 gave solutions that can go to a stable level (about 1.6) when time goes to infinity, however, the solutions from lsoda are decreasing to very very small (about 1e-130) numbers. Does R have more accurate ODE solvers as