similar to: Simplex Density Plots

Hello The excellent adapt package integrates over multi-dimensional hypercubes. I want to integrate over a multidimensional simplex. Has anyone implemented such a thing in R? I can transform an n-simplex to a hyperrectangle but the Jacobian is a rapidly-varying (and very lopsided) function and this is making adapt() slow. [ A \dfn{simplex} is an n-dimensional analogue of a triangle or

Full_Name: George F. LeCompte Version: 1.6.1 OS: Windows 98 Submission from: (NULL) (208.8.162.161) This may be a newbie problem. I am attempting tor unt the simplex routine from the boot package. The example code doesn't find simplex. What's wrong here? > help(simplex,package=boot) > # from the resulting article > > # This example is taken from Exercise 7.5 of

As I have previously asked, in response to a similar question: Is this a homework problem? cheers, Rolf Turner rolf at math.unb.ca

Hi, I need some help. I'm doing a project that demands me to obtain several simplex solutions and I would like to can keep the solution in a vector or something to be able to use it after I get it. The comand simplex() prints the solution but how can I keep it? Another alternative would be to export it to excel, how can I do this? I just see the solution and have to note it on a paper or

I have a set of linear equations and would like to find any feasible solution. A simplex solution works in Case 1 below, but not in Case 2. I would be grateful for any help. Case 1: Find any feasible solution for the set of linear equations: a + b + c = 5 a + b + 0c = 4 0a + b + c = 4 Solution - a feasible (and unique) solution is a=1, b=3, c=1. The following R code

Greetings! I want to follow the evolution of a Nelder-Mead function minimisation (a function of 2 variables). Hence each simplex will have 3 vertices. Therefore I would like to have a function which can output the coordinates of the 3 vertices after each new simplex is generated. However, there seems to be no way (which I can detect) of extracting this information from optim() (the

I am running the following code (testing the use of the simplex function to determine if a point is in the convex hull of another set of points or not): >a <- c(0, 0) >A3 <-matrix(c(1,2,3,4,1,1), ncol = 2, byrow = T) >b3 <-c(1.5, 3.5, 1) >simplex(a = a, A3 = A3, b3 = b3) and the following error message appears: Error in simplex1(out1$a[1:(n + m1 + m2)], out1$A[, 1:(n + m1

In trying to use simplex() from the boot package, I have run into a situation that doesn't seem like it should be possible. It is claiming that it has solved the LP, but returns a vector of all zeros, which does not satisfy the constraints I passed in. A small example: > ubMatrix <- matrix(c(1,1,-1,0,-1,-1), 3, 2) > ubVector <- c(2,1,-1) > objective <- c(0,1) >

I am interested in using the nonlinear forecasting techniques developed by Sugihara et al. In particular the simplex projection and the S-Map (see this website for details and reprints: http://iod.ucsd.edu/simplex/ ). I've looked through CRAN but could not find any package with functions that allow such analysis. Any pointers? Thanks, Manu

Dear R users, Is anyone familiar with the "n.iter" argument of the simplex() function (in the boot package)? It seems it doesn't have an effect no matter what value I set it ... I'm trying to solve a linear programming problem and running into the problem of simplex.object$solved = 0 or "A value of 0 indicates that the maximum number of iterations was reached without

Hello everybody. I found out the other day something quite astonishing (which I guess is not astonishing at all to those in the know): in d-dimensional space, determining whether a given point is inside the convex hull of a set of n points is elegantly and quickly solvable using linear programming. If the columns of matrix "ff" are the coordinates of the set of points, then in d=2

Hello, anyone knows if there is a way in R to draw contour on a simplex based on a function f(x,y,z) with domain (x+y+z = 1)? Thank you! gigi [[alternative HTML version deleted]]

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Dear list, Does anyone have a suggestion (or better still) code for sampling from the uniform distribution over the convex hull of a set of points? Many thanks and best wishes, Ranjan

I'm exploring the simplex algorithm with a simple transportation problem of the form: minimize: 8a + 6b + 10c + 9d + 5e + 7f subject to the constraints: a + b + c = 11 d + e + f = 14 a + d = 10 b + e = 8 c + f = 7 I've implemented this in R (1.4.0 (2001-12-19), SunOS 5.7) as: require(boot) costs = c(8,6,10,9,5,7) constraints = c( 1,1,1,0,0,0, 0,0,0,1,1,1, 1,0,0,1,0,0,

Dear useRs, upon request, the VGAM package (currently version 0.7-1) has been officially released on CRAN (the package has been at my website http://www.stat.auckland.ac.nz/~yee/VGAM for a number of years now). VGAM implements a general framework for several classes of regression models using iteratively reweighted least squares (IRLS). The key ideas are Fisher scoring, generalized linear and

Dear list members, I want to draw surfaces of Dirichlet distributions with different parameter settings. My code is the following: #<begin code> a1 <- a2 <- a3 <- 2 #a2 <- .5 #a3 <- .5 x1 <- x2 <- seq(0.01, .99, by=.01) f <- function(x1, x2){ term1 <- gamma(a1+a2+a3)/(gamma(a1)*gamma(a2)*gamma(a3)) term2 <- x1^(a1-1)*x2^(a2-1)*(1-x1-x2)^(a3-1)

I'm just getting started with R, having a lot of original work on modeling and exploring the simulation by MCMC. I want to simulate the prior and the posterior distribution of Dirichlet Process by MCMC. Is there anyone in NYC that might be a good tutor for me? -- Dr. P. NGOM, Facult? des Sciences et Techniques D?partement de Math?matiques et Informatique Universit? Cheikh Anta Diop Dakar -

Hola comunidad, Les consulto mi duda. Quisiera generar N números aleatorios tal que su suma esté predeterminada a un valor k. Sé que con la distribución Dirichlet, por ejemplo, se podrían obtener números aleatorios tal que su suma es la unidad. Por ejemplo MCMCpack::rdirichlet(1,rep(10,7)) genera 7 números tal que su suma es 1 (el parámetro rep(10,7) es cualquier cosa). Pero me pregunto si se

I have just checked the Openbsd box on the if interface. fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 address: 00:02:55:30:54:28 media: Ethernet autoselect (100baseTX full-duplex) status: active inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255 inet6 fe80::202:55ff:fe30:5428%fxp0 prefixlen 64 scopeid 0x1 xl0: