No, the two dimensions are the same. It's a dissimilarity matrix in the txt
file.
data[x][x]=0 data[x][y]=data[y][x] and 0<=data[x][y]<=1.



2008/9/3, stephen sefick <ssefick@gmail.com>:
>
> different dimensions?
>
> On Wed, Sep 3, 2008 at 8:13 AM, 陈武 <geminiwhu@gmail.com> wrote:
> > haha...wrong code again, it's isoMDS not sammon in the 5th line.
> > Thanks for Victor Lemes Landeiro's and Brian D. Ripley's advice.
> >
> >
> > ÔÚ08-9-3£¬Prof Brian Ripley <ripley@stats.ox.ac.uk> Ð´µÀ£º
> >>
> >> There is still no call to isoMDS in your code, and nothing we can
> >> reproduce.
> >>
> >> It all depends on the dissimilarity matrix you have not given us: maybe
> >> there is no good 2D representation of it.
> >>
> >> Looks like you need to ask a local expert about what you are doing, for
> >> this is a statistical and not an R question.
> >>
> >>
> >> On Wed, 3 Sep 2008, ³ÂÎä wrote:
> >>
> >> Sorry, wrong code. The right one here:
> >>>
> >>> library(MASS)
> >>> cl<-read.table("e:/data.txt",header=T,sep=",")
> >>> row.names(cl)<-colnames(cl)
> >>> cm<-as.matrix(cl)
> >>> loc<-sammon(cm)
> >>> jpeg(filename="e:/plot.gif",width = 480, height = 480, units = "px",
> >>> pointsize = 12, quality = 75, bg = "white", res = NA, restoreConsole =
> >>> TRUE)
> >>> plot(loc$points,type="p")
> >>> text(loc$points,rownames(cl),cex=1,pos=1,offset=1)
> >>> dev.off()
> >>>
> >>> And "e:/data.txt" contains a 40*40 dissimilarity matrix. Thanks for you
> >>> advices!
> >>>
> >>>
> >>> 2008/9/3, ???? <geminiwhu@gmail.com>:
> >>>
> >>>>
> >>>> I apply isoMDS to my data, but the result turns out to be bad as the
> >>>> stress
> >>>> value stays around 31! Yeah, 31 ,not 3.1... I don't know if I ignore
> >>>> something before recall isoMDS.
> >>>> My code as follow:
> >>>>
> >>>> m <- read.table("e:/tsdata.txt",header=T,sep=",")
> >>>> article_number <- ts(m, start = 2004,end=2008, frequency = 1
> >>>> ,names=colnames(m))
> >>>> jpeg(filename="e:/tsmap.gif",width = 480, height = 480, units = "px",
> >>>> pointsize = 12, quality = 75, bg = "white", res = NA, restoreConsole =
> >>>> TRUE)
> >>>> plot(article_number, plot.type="single",
> >>>> lty=c(1,1,1,1,1),col=c(1,2,3,4,5),las=1)
> >>>> max<-range(m)
> >>>> x<-c(2004,2004,2004,2004,2004)
> >>>>
> >>>>
> >>>>
> y<-c(max[2]*0.96,max[2]*0.9199999999999999,max[2]*0.88,max[2]*0.84,max[2]*0.7999999999999999)
> >>>> points(x,y,col=c(1,2,3,4,5),pch=15)
> >>>> text(x,y,colnames(m),pos=4,offset=0.4)
> >>>> dev.off()
> >>>>
> >>>> A 40*40 matrix in "e:/tsdata.txt". How should I do to improve the
> effect?
> >>>> Thank you!
> >>>>
> >>>>
> >>>        [[alternative HTML version deleted]]
> >>>
> >>
> >> --
> >> Brian D. Ripley,                  ripley@stats.ox.ac.uk
> >> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> >> University of Oxford,             Tel:  +44 1865 272861 (self)
> >> 1 South Parks Road,                     +44 1865 272866 (PA)
> >> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> >
> >        [[alternative HTML version deleted]]
> >
> >
> > ______________________________________________
> > R-help@r-project.org 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.
> >
> >
>
>
>
> --
> Stephen Sefick
> Research Scientist
> Southeastern Natural Sciences Academy
>
> Let's not spend our time and resources thinking about things that are
> so little or so large that all they really do for us is puff us up and
> make us feel like gods. We are mammals, and have not exhausted the
> annoying little problems of being mammals.
>
>        -K. Mullis
>

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