Hi,
The denominator i compute seperately counting how many observations there were
that were not NA. Thus the I divide each (n,m) cell by the number of counts it
was not NA.
Thanks,
Greg
On Sep 14, 2010, at 9:23 AM, Dennis Murphy wrote:
> Hi:
>
> It's certainly fast (0.97s for 10000 reps on my box), but doesn't replacement
> by zero affect the denominator of the sum, thereby deflating the means
> (assuming the contents of the matrices are nonnegative or NA)?
>
> Dennis
>
> On Tue, Sep 14, 2010 at 5:28 AM, Henrique Dallazuanna <www...@gmail.com>
> wrote:
> You can try this also:
>
> Reduce('+', lapply(mymats, function(x)replace(x, is.na(x), 0)))
>
>
> On Sun, Sep 12, 2010 at 10:36 PM, Gregory Ryslik <rsa...@comcast.net> wrote:
>
> > Hi Everyone,
> >
> > Thanks to everyone for their help. With your suggestions and some poking
> > around, the following works for what I need. It basically adds all the
> > matrices elementwise, and adds nothing if the element is NA. Thanks again!
> > Code below:
> >
> >
> > ******************************
> > mymats <- vector('list', 5)
> > set.seed(246)
> >
> > # Generate a list of five 3 x 3 matrices
> > for(i in 1:5) mymats[[i]] <- matrix(sample(1:9), nrow = 3)
> >
> > mymats[[5]][1,1]<-NA
> > mymats[[4]][2,2]<-NA
> > mymats
> >
> > matrixadder<-function(u,v){
> > na.u<-is.na(u)
> > na.v<-is.na(v)
> > ifelse(na.u & na.v, NA, ifelse(na.u, 0, u)+ ifelse(na.v,0,v))
> > }
> >
> > Reduce('matrixadder',mymats)
> > ******************************
> >
> > Cheers,
> > Greg
> >
> >
> >
> >
> > On Sep 12, 2010, at 8:33 PM, Ben Bolker wrote:
> >
> > > My next suggestion (I don't have time to work out or test an example
> > > at the moment):
> > >
> > > library(abind)
> > > tmparr <- abind(m1,m2,m3,...,along=3)
> > > OR
> > > tmparr <- do.call(c(matlist,list(along=3)))
> > > apply(tmparr,c(1,2),mean,na.rm=TRUE)
> > >
> > > or something along those lines.
> > >
> > > ______________________________________________
> > > 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.
> >
> >
> > [[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.
> >
>
>
>
> --
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
>
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>
>
> ______________________________________________
> 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.
>
>
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