similar to: e1071 SVM, cross-validation and overfitting

Hi, the new version 1.1-0 of package e1071 is now on CRAN. Changes: *) use libsvm 2.1 for support vector machines. We are now also a kind of ``official'' R frontend to libsvm and linked from their homepage at http://www.csie.ntu.edu.tw/~cjlin/libsvm *) new functions for comparing partitions Best, Fritz -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

Hello, I have an SVM model previously calibrated using libsvm R implementation from the e1071 package. I would like to use this SVM to predict values, from a Java program. I first tried to use jlibsvm and the "standard" java implementation of libsvm, without success. Thus, I am now considering writing data in files from my Java code, calling an R program to predict values, then gather

Dear listers, I'm using gam(from mgcv) for semi-parametric regression on small and noisy datasets(10 to 200 observations), and facing a problem of overfitting. According to the book(Simon N. Wood / Generalized Additive Models: An Introduction with R), it is suggested to avoid overfitting by inflating the effective degrees of freedom in GCV evaluation with increased "gamma"

I am analyzing particulate matter data (PM10) on a small data set (147 observations). I fitted a semi-parametric model and am worried about overfitting. How can one check for model fit in GAM? Jean G. Orelien

Dear David, Dear Friends, After any running svm I receive different results of Error estimation of 'svm' using 10-fold cross validation. What is the reason ? It is caused by the algorithm, libsvm , e1071 or something els? Which value can be optimal one ? How much run can reach to the optimality.And finally, what is difference between Error estimation of svm using 10-fold cross validation

I am starting to use svm from e1071 and I wonder how exactly crossvalidation is implemented. Whenever I run > svm.model <- svm(y ~ ., data = trainset, cross = 3) on my data I get dirrerent values for svm.model$MSE e.g. [1] 0.9517001 1.7069627 0.6108726 [1] 0.3634670 0.9165497 1.4606322 This suggests to me that data are scrambled each time - the last time I looked at libsvm python

Hello, I'm trying to understand how to use the pbo package by looking at a vignette. I'm curious about a part of the vignette that creates simulated returns data. The package author transforms his simulated returns in a way that I'm unfamiliar with, and that I haven't been able to find an explanation for after searching around. I'm curious if I need to replicate the

The subject is a Generalized Additive Model. Experts caution us against overfitting the data, which can cause inaccurate results. I am not a statistician (my background is in Computer Science). Perhaps some kind soul would take a look and vet the model for overfitting the data. The study estimated the ebb and flow of traffic through a voting place. Just one voting place was studied; the

This isn't a question about R, but I'm hoping someone will be willing to help. I've been looking at calibration plots in multiple regression (plotting observed response Y on the vertical axis versus predicted response [Y hat] on the horizontal axis). According to Frank Harrell's "Regression Modeling Strategies" book (pp. 61-63), when making such a plot on new data

A new version of e1071 has been released to CRAN which should be much easier to install on a lot of platforms because reading/writing PNM images has been moved to the pixmap package, hence there are no longer dependencies on external libraries and no configure mechanism. For the authors, Fritz Leisch ********************************************************** Changes in Version 1.2-0: o

Hey all, I can't seem to get the princurve package to produce correct results, even in the simplest cases. For example, if you just generate a 1 period noiseless sine wave, and ask for the principal curve and plot, the returned curve is clearly wrong (doesn't follow the sine wave). Here's my code: library(princurve) x <- runif(1000,0,2*pi); x <- cbind(x/(2*pi), sin(x)) fit1

Hi Joe, The centering and re-scaling is done for the purposes of his example, and also to be consistent with his definition of the sharpe function. In particular, note that the sharpe function has the rf (riskfree) parameter with a default value of .03/252 i.e. an ANNUAL 3% rate converted to a DAILY rate, expressed in decimal. That means that the other argument to this function, x, should be DAILY

Hi Eric, Thank you, that helps a lot. If I'm understanding correctly, if I?m wanting to use actual returns from backtests rather than simulated returns, I would need to make sure my risk-adjusted return measure, sharpe ratio in this case, matches up in scale with my returns (i.e. daily returns with daily sharpe, monthly with monthly, etc). And I wouldn?t need to transform returns like the

Correct Sent from my iPhone > On 21 Nov 2017, at 22:42, Joe O <joerodonnell at gmail.com> wrote: > > Hi Eric, > > Thank you, that helps a lot. If I'm understanding correctly, if I?m wanting to use actual returns from backtests rather than simulated returns, I would need to make sure my risk-adjusted return measure, sharpe ratio in this case, matches up in scale with

Wrong list. Post on r-sig-finance instead. Cheers, Bert On Nov 20, 2017 11:25 PM, "Joe O" <joerodonnell at gmail.com> wrote: Hello, I'm trying to understand how to use the pbo package by looking at a vignette. I'm curious about a part of the vignette that creates simulated returns data. The package author transforms his simulated returns in a way that I'm

Hi, I have a question about the parameter C (cost) in svm function in e1071. I thought larger C is prone to overfitting than smaller C, and hence leads to more support vectors. However, using the Wisconsin breast cancer example on the link: http://planatscher.net/svmtut/svmtut.html I found that the largest cost have fewest support vectors, which is contrary to what I think. please see the scripts

On 18/09/17 17:23, Ben Turner wrote: > Do you want tuned or untuned? If tuned I'd like to try one of my tunings for metadata, but I will use yours if you want. (Re-CC'd list) I would be interested in both, if possible: To confirm that it's not only my machines that exhibit this behaviour given my settings, and to see what can be achieved with your tuned settings. Thank you!

Hi, Recently, I installed the 1.1.0 version of R (for Windows), since it includes an implementation of Projection Pursuit (I failed to write my own version of PP as a standalone C++ program). As far as I know, R offers two interfaces/sintax for the ppr() function. The first one requieres a regression formula and a data frame. The other requieres X, a matrix with the explanatory variables, and Y,

[re-sending - previous email went out by accident before complete] Hi Joe, The centering and re-scaling is done for the purposes of his example, and also to be consistent with his definition of the sharpe function. In particular, note that the sharpe function has the rf (riskfree) parameter with a default value of .03/252 i.e. an ANNUAL 3% rate converted to a DAILY rate, expressed in decimal. That

On Aug 26, 2009, at 7:02 PM, David Vandevoorde wrote: >> It's actually the other way around. llvm has always ignored the >> "inline" keyword and now we are finding out we are missing some >> important cases. > > Okay. It's the "other way around" in terms of history, but it looks > like the conclusion might be the same: Purely heuristics-based