Displaying 20 results from an estimated 2000 matches similar to: "QP for solving Support Vector Regression"
2012 Mar 16
1
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
2009 Oct 04
3
error installing/compiling kernlab
Hi everybody,
I''m using R on a 64-bit Ubuntu 9.04 (Jaunty). I prefer to install R
packages from source, even if they are available in Synaptic. The
problem is that I can''t install/compile kernlab. Everything works fine
until it gets to the lazy loading part:
** preparing package for lazy loading
Creating a new generic function for "terms" in "kernlab"
2005 Oct 13
3
Optim with two constraints
Hi R-list,
I am new to optimization in R and would appreciate help on the following
question. I would like to minimize the following function using two
constraints:
######
fn <- function(par,H,F){
fval <- 0.5 * t(par) %*% H %*% par + F%*% par
fval
}
# matrix H is (n by k)
# matrix F is (n by 1)
# par is a (n by 1) set of weights
# I need two constraints:
# 1.
2009 Nov 29
2
kernlab's ksvm method freeze
Hello,
I am using kernlab to do some binary classification on aminoacid
strings.
I am using a custom kernel, so i use the kernel="matrix" option of the
ksvm method.
My (normalized) kernel matrix is of size 1309*1309, my results vector
has the same length.
I am using C-svc.
My kernlab call is something similiar to this:
ksvm(kernel="matrix", kernelMatrix, trainingDataYs,
2007 Dec 05
1
Quadratic programming
Hi,
I'm quite new at R and I haven't found the answer to my question anywhere on the net, so either it is trivial or not documented. So, bare with be.
I am using the quadprog package and its solve.QP routine to solve and quadratic programming problem with inconsistent constraints, which obviously doesn't work since the constraint matrix doesn't have full rank. A way to solve this
2009 Apr 28
1
kernlab - custom kernel
hi,
I am using R's "kernlab" package, exactly i am doing classification using
ksvm(.) and predict.ksvm(.).I want use of custom kernel. I am getting some
error.
# Following R code works (with promotergene dataset):
library("kernlab")
s <- function(x, y) {
sum((x*y)^1.25)
}
class(s) <- "kernel"
data("promotergene")
gene <- ksvm(Class ~ .,
2008 May 07
0
Fwd: Re: Solution of function
Forgot to send one copy to R help. Sorry
Megh Dal <megh700004@yahoo.com> wrote: Date: Wed, 7 May 2008 02:45:09 -0700 (PDT)
From: Megh Dal <megh700004@yahoo.com>
Subject: Re: [R] Solution of function
To: Berwin A Turlach <berwin@maths.uwa.edu.au>
Hi Berwin,
Thanks for having look on my problem. However on ipop() function I see following:
ipop solves the quadratic
2009 May 27
1
Constrained fits: y~a+b*x-c*x^2, with a,b,c >=0
I wonder whether R has methods for constrained fitting of linear models.
I am trying fm<-lm(y~x+I(x^2), data=dat) which most of the time gives
indeed the coefficients of an inverted parabola. I know in advance that
it has to be an inverted parabola with the maximum constrained to
positive (or zero) values of x.
The help pages for lm do not contain any info on constrained fitting.
Does anyone
2006 Nov 24
1
How to find AUC in SVM (kernlab package)
Dear all,
I was wondering if someone can help me. I am learning SVM for
classification in my research with kernlab package. I want to know about
classification performance using Area Under Curve (AUC). I know ROCR
package can do this job but I found all example in ROCR package have
include prediction, for example, ROCR.hiv {ROCR}. My problem is how to
produce prediction in SVM and to find
2005 Oct 19
1
ipop (kernlab) gives pars < lower bound ?
hi everyone,
ipop very quickly and accurately identifies the correct parameters in
a toy dataset i built, but when i use ipop on the real dataset i get
values for the parameters " primal(res) " that are less than zero,
even though i specify zero for the lower bound : l = rep(0,
length(c)) , where length(c) is the number of parameters i'm trying to
identify.
the parameters are
2011 Aug 26
1
kernlab: ksvm() bug?
Hello all,
I'm trying to run a gird parameter search for a svm.
Therefore I'M using the ksvm function from the kernlab package.
----
svp <- ksvm(Ktrain,ytrain,type="nu-svc",nu=C)
----
The problem is that the optimization algorithm does not return
for certain parameters.
I tried to use setTimeLimit() but that doesn't seem to help.
I suspect that ksvm() calls c code that
2009 Dec 25
2
Help with SVM package Kernlab
Hi useR's,
I am resending this request since I got no response for my last post and I
am new to the list so pardon me if I am violating the protocol.
I am trying to use the "Kernlab" package for training and prediction using
SVM's. I am getting the following error when I am trying to use the predict
function:
> predictSvm = predict(modelforSVM, testSeq);
Error in
2012 Aug 19
1
kernlab | ksvm error
Dear list,
I am using the ksvm function from kernlab as follows:
(1) learning
> svm.pol4 <- ksvm(class.labs ~ ., data = train.data, prob.model = T, scale
= T, kernel = "polydot")
(2) prediction
> svm.pol.prd4 <- predict(svm.pol4, train.data, type = "probabilities")[,2]
But unfortunately, when calling the prediction, once in every 10s of times
(using the exact
2006 Nov 27
0
kernlab 0.9-0 on CRAN
A new version of kernlab has just been released.
kernlab is a kernel-based Machine Learning package for R.
kernlab includes the following functions:
o ksvm() : Support Vector Machines for classification, regression,
novelty detection, native multi-class classification, support
for class-probability output and confidence intervals in
regression.
o gausspr()
2006 Nov 27
0
kernlab 0.9-0 on CRAN
A new version of kernlab has just been released.
kernlab is a kernel-based Machine Learning package for R.
kernlab includes the following functions:
o ksvm() : Support Vector Machines for classification, regression,
novelty detection, native multi-class classification, support
for class-probability output and confidence intervals in
regression.
o gausspr()
2012 Nov 15
1
Can't see what i did wrong..
with
pred.pca<-predict(splits[[i]]$pca,trainingData at samples)[,1:nPCs]
dframe<-as.data.frame(cbind(pred.pca,class=isExplosive(trainingData,2)));
results[[i]]$classifier<-ksvm(class~.,data=dframe,scaled=T,kernel="polydot",type="C-svc",
C=C,kpar=list(degree=degree,scale=scale,offset=offset),prob.model=T)
and a degree of 5 i get an error of 0 reported by the ksvm
2008 Jun 25
1
stringdot
Hi!!
I am trying to figure out how to use the string kernel "stringdot" in kernlab.
k <- function(x,y) {
(sum(x*y) +1)*exp(-0.001*sum((x-y)^2))
}
class(k) <- "kernel"
data(promotergene)
## train svm using custom kernel
gene.k <- ksvm(Class~.,data=promotergene,kernel=k,C=10,cross=5) # works fine in this case
gene.rbf <-
2012 Nov 29
1
Help with this error "kernlab class probability calculations failed; returning NAs"
I have never been able to get class probabilities to work and I am relatively new to using these tools, and I am looking for some insight as to what may be wrong.
I am using caret with kernlab/ksvm. I will simplify my problem to a basic data set which produces the same problem. I have read the caret vignettes as well as documentation for ?train. I appreciate any direction you can give. I
2008 Apr 10
2
QP.solve, QPmat, constraint matrix, and positive definite
hello all,
i'm trying to use QPmat, from the popbio package. it appears to be based
on solve.QP and is intended for making a population projection matrix.
QPmat asks for: nout, A time series of population vectors and C, C
constraint matrix, (with two more vectors, b and nonzero). i believe the
relevant code from QPmat is:
function (nout, C, b, nonzero)
{
if (!"quadprog" %in%
2009 Feb 16
2
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