[R] get index of elements in vector
Hello all Is There a fuction that return a index of a element in vector? like this semantic example: vector = c( 100, 200, 300 ) getINDEX( vector, value = 200 ) Thanks in advance for your attention. Cleber Borges __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] [R-pkgs] New package Ryacas
Hello, First, I would like to congratulations for very cool package! It's very nice idea!... Secondly, Is there a way to send R'objects (variables) to yacas and make symbolic operations?? for example: d <- diag(3) a <- "A" yacas( d * a ) Thanks, Cleber Borges Gabor Grothendieck wrote: >Ryacas is an R interface to the free yacas computer algebra >system. Ryacas allows one to send R expressions, >unprocessed yacas strings and certain other R objects to a >separate yacas process from R and get back the result. It >also has facilities for manipulating yacas strings and R >expressions destined for yacas processing. > >It can be used for exact arithmetic, symbolic math, ASCII >pretty printing and translating R to TeX. > > >Online info. For overview, pointers to additional >information, installation instructions and a sample session >see: > >http://code.google.com/p/ryacas/ > >The vignettes can be viewed online here: > >http://ryacas.googlecode.com/svn/trunk/inst/doc/Ryacas.pdf >http://ryacas.googlecode.com/svn/trunk/inst/doc/Ryacas-Sym.pdf > > >More. Once Ryacas is installed, pointers to additional >information can be found with these R commands: > >library(Ryacas) >package?Ryacas > > >--- > > __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] mcmcsamp - How does it work?
Hello, I am a chemical student and I make use of 'lme/lmer function' to handle experiments in split-plot structures. I know about the mcmcsamp and I think that it's very promissory. I would like knowing "the concept behind" of the mcmcsamp function. I do not want the C code of the MCMCSAMP function. I would like to get the "pseudo-algorithm" to understanding that it does. I accompanied the threads [1] and [2] and 'googled' several terms but I do not obtained success about this matter. [ 1 ] fixed effects following lmer and mcmcsamp - which to present? - 8/8/2006 [ 2 ] mcmcsamp-CI instead of P-values - references? - 3/10/2006 Thanks in advanced for yours attention! Cleber Borges __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R vs. Excel (R-squared)
I was quite interested in this thread (discussion), once that I am chemistry student and I work with Mixtures Designs that are models without intercept. I thought quite attention the follow afirmation: ' Thus SST, the "corrected" total sum of squares, should be used when you have a model with an intercept term but the uncorrected total sum of squares should be used when you do not have an intercept term. ' (Douglas Bates) I have as reference a book called: "Experiments with Mixtures: Designs, Models, and the Analysis of Mixture Data" second edition John A. Cornell (Professor of Statistics in University Of Florida) In this book, pg 42: item 2.7 - THE ANALYSIS OF VARIANCE TABLE, I have the model below: y(x) = 11.7x1 + 9.4x2 + 16.4x3 + 19.0x1x2 + 11.4x1x3 - 9.6x2x3 with the follow ANOVA Table: source of variationD.F.SSMS Regressionp-1SSR=\sum( y_{pred} - y_{mean} )^2ssR/(p-1) ResidualN-pSSE=\sum( y_{exp} - y_{pred} )^2ssE/(N-p) TotalN-1SSE=\sum( y_{exp} - y_{mean} )^2 pred = predicted exp = experimental and in many others books. I always see the ANOVA Table of Mixtures systems with SST, the "corrected" total sum of squares ( N-1 degrees freedom ). I would like to ask: 1) What is approach ( point view ) more adequate ? 2) Could someone indicate some reference about this subject ? Thanks a lot. Regards Cleber N. Borges Dados x1 x2 x3 y 10011 10012.4 0.50.5015 0.50.5014.8 0.50.5016.1 0108.8 01010 00.50.510 00.50.59.7 00.50.511.8 00116.8 00116 0.500.517.7 0.500.516.4 0.500.516.6 ## Model d.lm <- lm( y ~ -1 + x1*x2*x3 - x1:x2:x3, data = Dados ) ### Anova like in the book d.aov <- aov( y ~ x1*x2*x3 - x1:x2:x3, data = Dados ) SSR (fitted Model) = 128.296 Douglas Bates wrote: >On 1/24/06, Lance Westerhoff <[EMAIL PROTECTED]> wrote: > > >>Hi- >> >>On Jan 24, 2006, at 12:08 PM, Peter Dalgaard wrote: >> >> >> >>>Lance Westerhoff <[EMAIL PROTECTED]> writes: >>> >>> >>> >>>>Hello All- >>>> >>>>I found an inconsistency between the R-squared reported in Excel vs. >>>>that in R, and I am wondering which (if any) may be correct and if >>>>this is a known issue. While it certainly wouldn't surprise me if >>>>Excel is just flat out wrong, I just want to make sure since the R- >>>>squared reported in R seems surprisingly high. Please let me know if >>>>this is the wrong list. Thanks! >>>> >>>> >>>Excel is flat out wrong. As the name implies, R-squared values cannot >>>be less than zero (adjusted R-squared can, but I wouldn't think >>>that is what Excel does). >>> >>> >>I had thought the same thing, but then I came across the following >>site which states: "Note that it is possible to get a negative R- >>square for equations that do not contain a constant term. If R-square >>is defined as the proportion of variance explained by the fit, and if >>the fit is actually worse than just fitting a horizontal line, then R- >>square is negative. In this case, R-square cannot be interpreted as >>the square of a correlation." Since >> >>R^2 = 1 - (SSE/SST) >> >>I guess you can have SSE > SST which would result in a R^2 of less >>then 1.0. However, it still seems very strange which made me wonder >>what is going on in Excel needless to say! >> >>http://www.mathworks.com/access/helpdesk/help/toolbox/curvefit/ >>ch_fitt9.html >> >> > >This seems to be a case of using the wrong formula. R^2 should >measure the amount of variation for which the given model accounts >relative to the amount of variation for which the *appropriate* null >model does not account. If you have a constant or intercept term in a >linear model then the null model for comparison is one with the >intercept only. If you have a linear model without an intercept term >then the appropriate null model for comparison is the model that >predicts all the responses as zero. Thus SST, the "corrected" total >sum of squares, should be used when you have a model with an intercept >term but the uncorrected total sum of squares should be used when you >do not have an intercept term. > >It is disappointing to see the MathWorks propagating such an >elementary misconception. > >__ >R-help@stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > >. > > > __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] PowerPoint
Hello, IMHO, for the printer 1 - The best choice of graphics format is postscript ( PS ) in Microsoft ( M$ ), since you install the M$ Convert Pack [1]! Make a preview in PS file with EMF format! use epstool for this 2 - Enhanced MetaFile ( EMF ) in M$ and OpenOffice ( OOo) is not the same... This can be a problem! See pstoedit page [2] 3 - In OOo, I use the EPS file with the follow procedure: - save my graphic in PS - make to use de EPSTOOL for to produce EPS ( ps with tiff preview ) -> preview is a tiff graphic with low quality *note: emf can be also to included for preview - I need a PS-printer... in the case of NO-ps-printer, the tiff (low quality) will be printed! { :-( }, then, I make a PDF final report with ExtendendPDF! - this procedure also work in the M$-Word HTH, Cleber N. Borges {klebyn} --- [1] - http://www.microsoft.com/downloads/details.aspx?FamilyID=cf196df0-70e5-4595-8a98-370278f40c57&DisplayLang=en [2] - http://www.pstoedit.net/pstoedit [3] - http://www.3bview.com/epdf-home.html Marc Bernard wrote: >Dear All, > > I am looking for the best way to use graphs from R (like xyplot, curve ...) > for a presentation with powerpoint. I used to save my plot as pdf and after > to copy them as image in powerpoint but the quality is not optimal by so > doing. > > Another completely independent question is the following: when I use "main" > in the xyplot, the main title is very close to my plot, i.e. no ligne > separate the main and the plot. I would like my title to be well > distinguished from the plots. > > I would be grateful for any improvements... > > Many thanks, > > Bernard, > > > > >- > > [[alternative HTML version deleted]] > >__ >R-help@stat.math.ethz.ch mailing list >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > >. > > > __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html