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

Displaying 20 results from an estimated 2000 matches similar to: "How to do a target value search analogous to Excel Solver"

2003 Apr 21
4
nonlinear equation 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.
2012 Feb 12
3
Counting the loop-round of a "for"-loop
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
2007 Jun 19
1
Iterative Solver [Converting Matlab's solve()]
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
2003 Mar 08
2
Looking for non-central F quantile
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
2007 Jun 20
4
finding roots of multivariate equation
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
2008 Oct 04
1
back-solver: any R thing like TK!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
2023 Nov 06
2
non-linear regression and root finding
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
2009 Feb 08
3
general inverse solver?
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
2012 Jan 08
2
R package equivalent to Excel SOLVER - Paquete R equivalente a SOLVER de Excel
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
2008 Oct 05
1
Excel Solver Add-In / Alternatives
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
2007 Dec 13
1
[LLVMdev] Puzzle solver on LLVM 2.1
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
2012 Jul 18
1
Defining a variable outside of optim or differential equation solver.
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
2009 Jul 08
2
i need same function solver in excel..
hi.. i used R a few days.. who can call me? same function solver in excel. _________________________________________________________________ [[elided Hotmail spam]] [[alternative HTML version deleted]]
2010 Sep 10
4
Solver in R
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]]
2012 Oct 24
1
equation solver
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
2013 Feb 20
2
'gmm' package: How to pass controls to a numerical solver used in the gmm() function?
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
2013 May 02
2
ODE solver
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 ?
2004 Jan 14
2
nonlinear regression and Excel solver
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
2004 Sep 16
3
newbie needs help using R as solver
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
2010 Sep 16
1
More accurate ODE solver?
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