search for: simplex

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 tetrahedron. It is the convex hull of...

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 Gill, Murray, > # and Wright (1991). > enj <- c(20...

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...

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: flags=8843&l...

Hello, I have just started using R, and have found it quite easy to make plots of probability densities for normal and beta distributions, etc. Now, I'm looking at trying to make a simplex plot of a Dirichlet density, but have gotten stuck and was hoping that someone could help. Ideally, the plot would look something like the 3d plots on Wikipedia here: http://en.wikipedia.org/wiki/File:Dirichlet_distributions.png Although if these are impossible, a color-coded 2d simplex would work...

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 'trace' argument to 'control...

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 follow...

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[...

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...

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

...inear programming. If the columns of matrix "ff" are the coordinates of the set of points, then in d=2 dimensions with n=4 constraints you can test whether point "candidate" is inside the convex hull by: R> candidate <- c(0.2,0.2) R> a <- rep(1,4) R> isin <- simplex(a=a, A3=ff, b3 = candidate) R> #[ff is given below]. Here, simplex() finds the x which minimizes a%*%x subject to ff%*%x = candidate [this works fine; candidate is inside the convex hull generated by the origin and the four points specified by the columns of ff because sum(isin$soln) <= 1]....

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(8,6,1...

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 re...

This is ifconfig on openbsd box: fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 I think this output shows that the fxp0 interface is on simplex mode. The voice degradation I referred was by using xlite soft phone. I open 2 line similtaneously and dial to FWD and back to my incoming extension. Xlite is runnning on a w2k box with realtek 100M nic in au...

Dear R users, I am pleased to announce the release of three new R packages: optimbase, optimsimplex, and neldermead. - optimbase provides a set of commands to manage an abstract optimization method. The goal is to provide a building block for a large class of specialized optimization methods. This package manages: the number of variables, the minimum and maximum bounds, the number of non linear i...

Dear R users, I am pleased to announce the release of three new R packages: optimbase, optimsimplex, and neldermead. - optimbase provides a set of commands to manage an abstract optimization method. The goal is to provide a building block for a large class of specialized optimization methods. This package manages: the number of variables, the minimum and maximum bounds, the number of non linear i...

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...while bridge0 doesn't, it seems to be OK: ----- bs1% uname -a FreeBSD bs1.sp34.ru 7.0-STABLE FreeBSD 7.0-STABLE #0: Sun May 25 20:15:26 MSD 2008 root@bs1.sp34.ru:/usr/obj/usr/src/sys/BSM i386 bs1% ifconfig em0; ifconfig tap0; ifconfig bridge0 em0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=98<VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM> ether 00:0c:f1:6c:37:4c inet 192.168.16.30 netmask 0xffffff00 broadcast 192.168.16.255 media: Ethernet autoselect (100baseTX <full-duplex>) status: active tap0: flags=8943<UP,BROADCAST,RUNNING,PROMIS...

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]]

Hi, I am having trouble using constrOptim. My target is to do a portfolio optimization and there some constraints have to be fulfilled. 1) The weight of each share of the portfolio has to be greater than 0 2) The sum of these weights has to be 1 I am able to fulfill either the first or the second constraint but not both. One simple way would be to fulfill the first constraint by using optim as