similar to: Help with factorized argument in solve.QP

Displaying 20 results from an estimated 300 matches similar to: "Help with factorized argument in solve.QP"

2009 Feb 16
solve.QP with box and equality constraints
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
2005 Jan 13
how to use solve.QP
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
2005 Nov 29
Constraints in Quadprog
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
2010 Dec 04
Quadratic programming with semi-definite matrix
Hello. I'm trying to solve a quadratic programming problem of the form min ||Hx - y||^2 s.t. x >= 0 and x <= t using solve.QP in the quadprog package but I'm having problems with Dmat not being positive definite, which is kinda okay since I expect it to be numerically semi-definite in most cases. As far as I'm aware the problem arises because the Goldfarb and Idnani method first
2006 Nov 08
Solving a maximization problem using QUADPROD
Hello, here is an example from the manual. How to turn this minimization problem into maximization problem, i.e. -(0 5 0) %*% b - 1/2 b^T b? # Assume we want to minimize: -(0 5 0) %*% b + 1/2 b^T b # under the constraints: A^T b >= b0 # with b0 = (-8,2,0)^T # and (-4 2 0) # A = (-3 1 -2) # ( 0 0 1) # we can use solve.QP.compact as follows: # library(quadprog) Dmat <- matrix(0,3,3)
2004 Sep 01
not positive definite D matrix in quadprog
Hello to everybody, I have a quadratic programming problem that I am trying to solve by various methods. One of them is to use the quadprog package in R. When I check positive definiteness of the D matrix, I get that one of the eigenvalues is negative of order 10^(-8). All the others are positive. When I set this particular eigenvalue to 0.0 and I recheck the eigenvalues in R, the last
2010 Dec 06
use pcls to solve least square fitting with constraints
Hi, I have a least square fitting problem with linear inequality constraints. pcls seems capable of solving it so I tried it, unfortunately, it is stuck with the following error: > M <- list() > M$y = Dmat[,1] > M$X = Cmat > M$Ain = as.matrix(Amat) > M$bin = rep(0, dim(Amat)[1]) > M$p=qr.solve(as.matrix(Cmat), Dmat[,1]) > M$w = rep(1, length(M$y)) > M$C = matrix(0,0,0)
2012 Mar 16
quadprog error?
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
2007 Jul 11
Some questions about quadratic programming (QP)
Dear R Users , As a beginner in QP, I'm trying to solve a Support Vector Machine problem by a QP. In particulare I am using the quadprog package. My questions are here: 1- In the document for the package (The quadprog Package), the inequality constraint is mentioned with >= , however in a standard QP, this usaully is written with <= . This constraint should be multiplied by a
2006 Feb 01
output hessian matrix in constrOptim
Hi, Is there any way to get the hessian matrix from the "constrOptim" function without supplying gradient function? Thanks. --------------------------------- Bring words and photos together (easily) with [[alternative HTML version deleted]]
2003 Jun 13
RDCOM Client: processes not terminating
Hello I am using Duncan Lang's RDCOM Client package (available on under R 1.7.0 and Windows XP Pro. Is this the right forum for questions about this package? In case it is, here is my question: Instances of COM objects do not seem to terminate as expected, but leave residual processes running. For example, if I try the simple example: E <-
2003 Jul 21
RODBC: problem saving a new table in an "Excel database"
Hi I am using package RODBC version 1.0-1 under R version 1.7.1 on Windows XP Pro. I am having problems writing a new table to an (Excel) database using sqlSave. I connect to an empty Excel spreadsheet using odbcConnectExcel (which, I believe, uses the Microsoft Excel Driver DSN). Then I try and save a new table to the database(spreadsheet) using SqlSave, but obtain an error message. Below is
2018 Feb 15
Help with factorized argument in solve.QP
Hello David, same problem here with solve.QP. dykstra is causing problems as well and giving for the value NA if factorized = TRUE: library(quadprog) library(Dykstra) R<-cbind(c(1,1),c(0,1)); d<-c(t(R)%*%R%*%c(2,1)) solve.QP(solve(R),d,-as.matrix(c(1,1)),-2,1,factorized = TRUE) S<-t(R)%*%R; solve.QP(S,d,-as.matrix(c(1,1)),-2,1)
2018 Mar 05
Interpret List Label as Date from Quantmod getOptionChain
On 5 March 2018 at 03:13, Sparks, John wrote: | library(quantmod) | #in fairness, I did not include this last time and my example was therefore not reproducible. Apologies to Bert and everyone else #for not following the posting guidelines. | aapl_total<-getOptionChain("AAPL", NULL)> | | How could I then get the subset of the entire list which only has expiry dates in 2019, or
2003 Apr 03
Matrix eigenvectors in R and MatLab
Dear R-listers Is there anyone who knows why I get different eigenvectors when I run MatLab and R? I run both programs in Windows Me. Can I make R to produce the same vectors as MatLab? #R Matrix PA9900<-c(11/24 ,10/53 ,0/1 ,0/1 ,29/43 ,1/24 ,27/53 ,0/1 ,0/1 ,13/43 ,14/24 ,178/53 ,146/244 ,17/23 ,15/43 ,2/24 ,4/53 ,0/1
2007 Dec 22
regarding lack of quadratic term in solve.qp
I was thinking about my solve.qp problem on my way home tonight and I think I can fix it by making Dmat the identity matrix. I'll check this weekend to make sure but my thinking is that doing this will make all the "variances" the same so that they shouldn't come into play during the evaluation of the objective function. Thanks though for any confirmation of this or other
2008 Jan 25
How to execute R code
Hi, I have 'R' code in file. saved it as exmaple.r here is the code....... library("hopach") GSE <- read.table("gene_expression_data",sep="\t",header=TRUE,row.names=TRUE) gene.dist <- distancematrix(t(GSE),d="euclid") gene.hobj <- hopach(t(GSE), dmat=gene.dist, mss="med") labelstosil(gene.hobj$cluster$label,gene.dist) I dont
2013 Jun 11
'Boolean Index too long'
#Hi, I am trying to run an MRPP with community data (spp-site-matrix). I use the following code: mzbtaxa_mrpp <- mrpp(mzbdist,mzbsites$Site) #mzbdist being a distance object (Bray-Curtis similarity matrix) derived from my sqrt transformed community data set, created with function 'vegdist', mzbsites$Site refers to factors structuring my community. #when I run this code, I get the
2011 May 11
Problem with constrained optimization with maxBFGS
Dear all, I need to maximize the v: v= D' W D D is a column vector ( n , 1) W is a given matrix (n, n) subject to: sum D= 1 (BTW, n is less than 300) I´ve tried to use maxBFGS, as follows: ##################################### objectiveFunction<-function(x) { return(t(D)%*%W%*%D) } Amat<-diag(nrow(D)) Amat<-rbind((rep(-1, nrow(D))), Amat) bvec<-matrix( c(0), nrow(D)+1,
2005 Dec 14
mysql connection problems
Hi hi i have a problem trying to connect to the mysql database when I do a rake it says: Access denied for user: ''@localhost'' to database '''' My database.yml file is fine Any ideas why this is happening -- Posted via