search for: qda

Hi, What does this mean when I have something like: > qda.boot <- boot(train, qda.bootstrap, R = 500) Error in qda.default(structure(data.matrix(x), class = "matrix"), ...) : Rank deficiency in group M with my qda.bootstrap() looks something like: > qda.bootstrap <- function(data, index) { + boot.qda <- qda(x = data[index, 2:9],...

z <- qda(train, cl) save(z, file = "qda.dat") load("qda.dat") predict(qda.dat, test)$class I'm trying to save z where z <-qda(train, cl) and load z for later use in predict(z, test)$class. I think I successfully saved z by save(z, file = "qda.dat") but when I tried to l...

Hi all! I am Angela, an Italian researcher and I am looking for an application that allows working in team, making a shared codebook, share a text database and code it. I tried AnSWR (the CDC''s QDA application) but its installation is too complicated for students and it is not working on latest version of Windows. What about Weft? Is it possible to share a project or, at least, merge different projects, including a codebook? Thank you in advance Ciao Angela ==============================...

...unction) vs. "prior=c(0.5, 0.5)", the results are different. The (0.5, 0.5) priors give better 1-classify-to-1 rate, and the proportional priors(default, no priors specified in the lda function) give better 0-classify-to-0 rate, for both training and testing data sets. However, if I run QDA on the same data (2-class classification) with default(no priors specified in the lda function) vs. "prior=c(0.5, 0.5)", the results are the same, i.e. the confusion tables are completely the same for two types of priors, I even tried "qda" function with "prior=c(0.3, 0.7)...

Hello, I am Souradeep Chattopadhyay and I am a graduate student at Iowa State University Department of Statistics. Can anyone please explain the mathematical formulation behind the scaling matrix returned by the qda function in MASS package. I want to understand how this scaling matrix is derived from the inputs given to the qda function. Example Code The following example is using the banknote data in the MCLUST package. *Code* require(MASS) require(mclust) data(banknote) quad<-qda(banknote[,-1], group...

You need to learn how to access code for nonexported methods. See ? "::" > methods(qda) [1] qda.data.frame* qda.default* qda.formula* qda.matrix* see '?methods' for accessing help and source code Shows you that the methods are not exported from the namespace. Hence you need to use the triple colon operator to see their code: > MASS:::qda Once you have the code, I...

I guess the question that is being asked here is what is the scaling matrix that is being returned in the qda object. The help file on qda() says: ... scaling: for each group ?i?, ?scaling[,,i]? is an array which transforms observations so that within-groups covariance matrix is spherical. ... This is a bit ambiguous. I tried a few cases (spectral, QR decomposition, especially given that it is an upper tr...

Dear R user, I'm using qda (quadratic discriminant analysis) function (package MASS) to classify 58 explanatory variables (numeric type with different ranges) using a grouping variable (factor 2 levels "0" "1"). I'm using the qda method for class 'data.frame' (in this way I don't need t...

can you run weft qda on mac with virtual PC? (this is how nvivo and some others work for the mac). us poor mac users...but i commend the open source effort! best, Lisa Lisa Schwartz Language Reading and Culture University of Arizona ____________________________________________________________________________...

Dear wxruby users I''ve been trying to get wxruby-based weft-qda 0.9.6 running on a linux from scratch 6.1 system (this list had a discussion about weft-qda last year and alex fenton''s also been trying to help me out - no luck so far). I get stuck with wxruby 0.60 (I think). I compiled wxruby against wxGTK 2.4.2 (without gtk2, without unicode - gtk+ v...

Hi, the following strange error appears when I use qda: > qda1 <- qda(as.data.frame(mfilters[cvtrain,]),as.factor(traingroups)) Error: function is not a closure That's also strange: > qda1 <- qda(mfilters[cvtrain,],as.factor(traingroups)) Error in qda.default(mfilters[cvtrain, ], as.factor(traingroups)) : length of dimnames must mat...

Dear list, (I've not upgraded to R1.4 yet) I have the following $class component in a predict.qda object: > unique(mod23S.qda.pred$class) [1] 12 17 8 10 4 9 5 13 14 19 20 15 6 3 7 1 23 11 18 21 16 2 22 NA Levels: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Nevertheless, when I try to identify the individual(s) with NA, I get: > any(is.na(mod23S.qda.pred$class))...

...;super-document" (a mailing list). I have looked at several tools and I like that Weft is public domain and written in Ruby, so I want to figure out whether it suits my set of requirements. In particular I would like to find out, whether there is a possibility that I could extend WeftQDA to allow me to import a mailbox-file as a hierarchical set of documents. Idealy I would like these documents to be sorted by date with replies being nested documents with some ability to search by author and subject of the email. One could put this as a more general feature for importing and...

Dear R Help Members, I am aware how to plot the LD1 vs LD2 from a lda in R, using the code: plot(baseline.systat.hat$x, col=baseline.systat.hat$class,pch=as.numeric(baseline.systat.hat$class)) However, I need to use the quadratic discriminant function, qda due to data properties. Is there a way to obtain the same sort of plot for from a qda object (and the output of predict qda). I have not been able to find this and am a bit stumped. I cannot seem to find any information on plotting this. Thank you, Melanie ________________________________________...

Hi Weft QDA 1.0.1''s available now. It''s a bug-fix and maintenance release, and a recommended upgrade for existing users. What''s new: - fix for crash when moving categories using the Category Tree - fixed a bug on Win 98 and Win ME that made Weft a ''non-starter'' -...

Hi, I have been using some of the functions in r for classification purposes, chiefly lda, qda, knn and nnet. My problem is that the only one I can figure out how to represenent graphically is lda (using plot.lda). I have tried 'fooling' this function into accepting qda input for plotting but to no avail. I wonder if you have any suggestions? Thanks alot, Anne Marie Power Marine...

I''ve encountered a small problem--some of the documents in my Documents and Categories window are not opening, while others are. Have others experienced this issue? If so, do you know how I might fix it? The coded segments of text are still there when I open up the categories with which documents have been tagged, but I can''t seem to pull up the whole text of some of these

Hi, I'm a R newbie and I have a supervised 2-class classification problem. To find out the best representation of my data (dim = 45). I want to perform LDA und QDA on the diffrent data representations to find out, which is best to discriminate the 2 sets. For LDA there exists a method plot.lda shows (in the 2 class case) a histogramm of the data, projected onto the linear discriminants (pleas correct me if i'm wrong...). Now to my question: Is there a si...

Hi, my name is Leandro and im Argentinian. I plan to build a web CMS on ruby on rails, to provide CAQDAS functionality, and since im building the site in Ruby on Rails and open source, i want to know if Weft QDA engine is open source. If so, id would come in handy to be able to reuse/improve an existing ruby based CAQDAS. I''d like to emphasize the fact that i dont mean to profit from it, or...

...e-mail question: I am trying to select variables through a quadratic discriminant analysis. It seems to me that a robust criterion is the value of the discriminatory power (i.e. the ratio of the separation of the class means to within-class variance) How can I obtain this ratio from V & R's qda() output ? Thanks (I hope this question is relevant) -- Daniel AMORESE Lab. M2C "Morphodynamique Continentale et C?ti?re" UMR CNRS 6143 Caen/Rouen Centre de G?omorphologie UCBN (Universit? de Caen Basse-Normandie) 14032 Caen Cedex FRANCE Ph: +33 (0)2 31 56 57 19 Fax: +33 (0)2 31 56 57 57...