similar to: a more specific question about qda

Displaying 20 results from an estimated 700 matches similar to: "a more specific question about qda"

2002 May 23
5
logistic regression or discriminant analysis ?
Hello, Does logistic regression really provide better results than lda or qda ? (my purpose is not classification but highlighting of discriminant variables). If this is true, where could I get an R script performing stepwise logistic regression ? Thanks -- Daniel AMORESE Lab. M2C "Morphodynamique Continentale et C?ti?re" UMR CNRS 6143 Caen/Rouen Centre de G?omorphologie UCBN
2009 Dec 23
2
A package for visualizing R syntax
Dear all, I have written a small set of functions for drawing graphical representations of R objects and evaluations of R expressions. It is mainly intended for pedagogical purposes. Here are some samples: http://panini.u-paris10.fr/~sloiseau/sampleGraphics.pdf The idea is to use some graphical conventions in order to make clear the abstract syntax and to explain function, extraction,
2003 May 22
1
Getting the Bootstrap Error Rate of 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], group = data[index, 1]) + qda.pred
2003 Nov 15
1
Loading file to use with qda()
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 load by load("qda.dat") and call predict(qda.dat, test)$class, it gives me error
2006 Mar 11
2
weird! QDA does not depend on priors?
Hi all, If I run LDA 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 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,
2017 Aug 23
2
Scaling Matrix in qda() function in MASS package
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
2007 Jul 25
1
qda(MASS) function error
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 to specify a formula). Using the function:
2017 Aug 23
0
Scaling Matrix in qda() function in MASS package
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
2017 Aug 24
1
Scaling Matrix in qda() function in MASS package
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
2003 Feb 27
2
qda plots
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 lab.
2010 Dec 07
9
[Weft QDA users] working on team using weft
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
2005 Oct 22
6
wxruby.so error with weft-qda
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+ version is 1.2.10) - after
2013 Feb 20
1
Plotting Discriminants from qda
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
2004 Jan 19
1
qda problem
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 match that of dims Some backgroud: >
2007 Oct 30
3
[Weft QDA users] Using WeftQDA for Mailing-List Analysis
Hi Alex, Hi Weft-Users! I am looking for a tool for doing a qualitative analysis of mailing-list data. This means I have a *lot* of individual documents (the typical case: around 500-5000 emails), belonging to the same "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
2001 Dec 20
4
conflicting results on NA in a qda predicted object:
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: >
2008 Mar 12
1
[Weft QDA users] Hello all
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,
2004 Jul 03
1
graphic representation of a qda object
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
2007 Aug 20
2
[Weft QDA users] Weft on Ubuntu -- Ctrl-shortcuts NOT working?
Hi -- have just followed Christophe''s notes to get Weft QDA up and running on my IBM Thinkpad T20 w/Ubuntu 6.06 (Dapper Drake). Am just going thru the manual and trying various things, as I''m new to qualitative analysis AND new to QDA tools. Anyway, one thing I''ve found is that many (and maybe ALL?) of the CTRL-shortcuts mentioned in the documentation are not working
2011 Apr 08
2
[Weft QDA users] Shifty Markings - round 2
Good Afternoon, I''m new to the mailing list and was wondering if anyone could help me with my current headache. I saw in the previous posts that someone else has had the problem of shifty markings. I too am finding the text immediately above what I wrote appearing in the coding reports, even though the coding in the documents themselves remains as it should. The project involves