similar to: regression constraints (again)

Thank you Brian Ripley, Gardar Johannesson, and Marcel Wolbers for your prompt and friendly help! I will share any further learnings as I move through these suggestions. -Bob Abugov Brian Ripley wrote: I just use optim() on the sum of squares with non-negativity constraints. That did not exist in 1999. Gardar Johannesson wrote: You can always just use the quadratic programing library in R

Dear list, I am trying to follow an example that estimates a 2x2 markov transition matrix across several periods from aggregate data using restricted least squares. I seem to be making headway using solve.QP(quadprog) as the unrestricted solution matches the example I am following, and I can specify simple equality and inequality constraints. However, I cannot correctly specify a constraint

I'm trying to find a good way of attaching a list within a function such that the attached variables (the list's members) precede the global environment (.GlobalEnv) in the search list. Here is a non-working example using attach(), which hopefully explains better what I'm trying to do: > foo <- function(x=0, input=list(a=10)) { + attach(input) + on.exit(detach(input)) +

I got this wired behaviour of the attr() function using R-1.6.1 on both linux redhat 7.3 (i386) and Solaris 8 (Sparc): > tmp <- list(id=1) > > attr(tmp,"n.ch") <- 2 > attr(tmp,"n") <- 1 > tmp $id [1] 1 attr(,"n.ch") [1] 2 attr(,"n") [1] 1 > > attributes(tmp) $names [1] "id" $n.ch [1] 2 $n [1] 1 >

I'm having difficulty figuring out how to implement the following set of constraints in Quadprog: 1). x1+x2+x3+x4=a1 2). x1+x2+x5+x6=a2 3). x1+x3+x5+x7=a3 4). x1+x2=b1 5). x1+x3=b2 6). x1+x5=b3 for the problem: MIN (x1-c1)2+(x2-c2)2+...+(x8-c8)2. As far a I understand, "solve.QP(Dmat, dvec, Amat, bvec, meq=0, factorized=FALSE)" reads contraints using an element-by-element

This might be because I didn't get it right, but; I thought R would release memory back to the system as (big) objects get removed? Here is my platform (with 1Gb of RAM): platform sparc-sun-solaris2.8 arch sparc os solaris2.8 system sparc, solaris2.8 status major 1 minor 3.1 year 2001 month 08 day 31 language R A little example: Start a new section of R, with

This is a little success story about the benefits of changing the defaults in config.site when I was building R-1.4.0 for Solaris (on a Sun Sparc that I'm currently using). For previous versions of R, I had just used the default config.site and not given it any thought. Since the Sun machine that I'm using is not getting any faster, I decided I would give config.site a look when building

I have this 'odd' problem; I need to let R pause, for a given time, before starting next iteration in a loop. I'm using the following to do this task, but feel a little bit guilty because I'm using as much CPU time as I can get while pausing: while(keepGoing) { t.end <- proc.time()[3] + 5 ## the time this loop should end at [block of R commands] while(proc.time()[3]

Hi everybody, I'm using Windows XP Prof, R 2.5.1 and a Pentium 4 Processor. Now, I want to solve a quadratic optimization program (Portfolio Selection) with the quadprog package I want to minimize (\omega'%*%\Sigma%*%\omega) Subject to (1) \iota' %*% \omega = 1 (full investment) (2) R'%*%\omega = \mu (predefined expectation value) (3) \omega \ge 0 (no short sales). Where

At the risk of ridicule for my deficient linear algebra skills, I ask for help using the solve.QP function to do portfolio optimization. I am trying to following a textbook example and need help converting the problem into the format required by solve.QP. Below is my sample code if anyone is willing to go through it. This problem will not solve because it is not set up properly. I hope I

Hi list: This is my first time to post my question on the list. Thanks for your help. I am solving a quadratic programming using R. Here is my question: w = arg min 0.5*w'Mw - w'N s. t. sum(w) = 1; w>0 note: w is weight vector, each w_i must >=0, and the sum of w =1. Here is my R code: A <-matrix(c(2.26,1.26,1.12,1.12,2.27,1.13,1.12,1.13,2.2),3,3); B <-

I have been trying out R-1.6.0 tarballs (2002-9-10 and 2002-9-17) on: arch sparc os solaris2.8 system sparc, solaris2.8 status beta major 1 minor 6.0 year 2002 month 09 day 17 language R As you see form above, R-1.6.0 compiles fine and works. However, when I "make fullcheck" I get the following error: running code in 'tools-Ex.R' ... OK

I have been playing around with sparse matrices in the Matrix package, in particularly with the Cholesky factorization of matrices of class dsCMatrix. And BTW, what a fantastic package. My problem is that I have to carry out repeated Cholesky factorization of a spares symmetric matrices, say Q_1, Q_2, ...,Q_n, where the Q's have the same non-zero pattern. I know in this case one does

Hi, I'm using the package quadprog to solve the following quadratic programming problem. I want to minimize the function (b_1-b_2)^2+(b_3-b_4)^2 by the following constraints b_i, i=1,...,4: b_1+b_3=1 b_2+b_4=1 0.1<=b_1<=0.2 0.2<=b_2<=0.4 0.8<=b_3<=0.9 0.6<=b_4<=0.8 In my opinion the solution should be b_1=b_2=0.2 und b_3=b_4=0.8. Unfortunately R doesn't find

Hi. Here are three successive examples of simple quadratic programming problems with the same structure. Each problem has 2*N variables, and should have a solution of the form (1/N,0,1/N,0,...,1/N,0). In these cases, N=4,5,6. As you will see, the N=4 and 6 cases give the expected solution, but the N=5 case breaks down. >cm8 [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [1,] 1 0

I forgot to attach the problem data, 'quadprog.Rdata' file, in my prior email. I want to report a following error with quadprog. The solve.QP function finds a solution to the problem below that violates the last equality constraint. I tried to solve the same problem using ipop from kernlab package and get the solution in which all equality constraints are enforced. I also tried an old

This is something that I have not seen in earlier beta versions of 1.6.0: . . . ts.plot text html latex example ts.union text html latex example tsSmooth text html latex tsdiag text html latex example R_LIBS= ../../../bin/R CMD INSTALL ERROR: no packages

Dear list members, I am trying to get information on how to fit a linear regression with constrained parameters. Specifically, I have 8 predictors , their coeffiecients should all be non-negative and add up to 1. I understand it is a quadratic programming problem but I have no experience in the subject. I searched the archives but the results were inconclusive. Could someone provide suggestions

The question was: > I have this 'odd' problem; I need to let R pause, for a given time, before > starting next iteration in a loop. I'm using the following to do this > task, but feel a little bit guilty because I'm using as much CPU time as I > can get while pausing: > > while(keepGoing) { > t.end <- proc.time()[3] + 5 ## the time this loop should end

I have a set of data for US t-bill returns and US stock returns frm 1980-2012. I am trying to bootstrap the data and obtain the minimum variance portfolio and repeat this portfolio 1000 times. However I am unable to get the correct code function for the minimum variance portfolio. When I tried to enter Opt(OriData+1, 1, 5, 0), I get "error:subscript out of bounds" Please help!