R help - May 2006 - Analog to matlab repmat function

Hello,

 I'm trying to switch from Matlab to R-project, and having some
difficulties.
 I make a use of multidimensional matrices. For example, I need to extract
 mean from one of the dimensions:

 % we have matrix data of size: 130 x 11 x 350 x 2
 data = data - repmat(mean(data,3),[130 1 1 1]);

 In R project I managed to do that in a very pervarsive way:

 # mean(data,3) in R
 base <- apply(data,c(2,3,4),mean)
 # repmat(...,[130 1 1 1])
 base <- rep(base,130)
 dim(base) <- c(11,2,350,130)
 base <- aperm(base,c(4,1,2,3))
 # data = data - repmat
 data <- data - base;

 Could you please show me a more elegant way of doing the same in R :)

Thanks, Daniil.

Oops, mistake, should be

data = data - repmat(mean(data,1),[130 1 1 1]);

Sorry.

On 5/29/06, Daniil Ivanov <daniil.ivanov at gmail.com>
wrote:
> Hello,
>
>  I'm trying to switch from Matlab to R-project, and having some
difficulties.
>  I make a use of multidimensional matrices. For example, I need to extract
>  mean from one of the dimensions:
>
>  % we have matrix data of size: 130 x 11 x 350 x 2
>  data = data - repmat(mean(data,3),[130 1 1 1]);
>
>  In R project I managed to do that in a very pervarsive way:
>
>  # mean(data,3) in R
>  base <- apply(data,c(2,3,4),mean)
>  # repmat(...,[130 1 1 1])
>  base <- rep(base,130)
>  dim(base) <- c(11,2,350,130)
>  base <- aperm(base,c(4,1,2,3))
>  # data = data - repmat
>  data <- data - base;
>
>  Could you please show me a more elegant way of doing the same in R :)
>
> Thanks, Daniil.
>

Thanks a lot to all of you!

 Now I see, that use of R (and S) is very different from use of Matlab.
 There is no one-to-one correspondence.
 I'm shy to ask so stupid questions, but name of language R
 makes it hard to find relevant links trough google.
 Thanks for pointing to "S Poetry", I would never find it alone,
 since I was looking for R-related info.

Thanks, Daniil.

On 5/29/06, Patrick Burns <pburns at pburns.seanet.com>
wrote:
> S Poetry may be of use to you.
>
>
> Patrick Burns
> patrick at burns-stat.com
> +44 (0)20 8525 0696
> http://www.burns-stat.com
> (home of S Poetry and "A Guide for the Unwilling S User")
>
> Daniil Ivanov wrote:
>
> >Hello,
> >
> > I'm trying to switch from Matlab to R-project, and having some
difficulties.
> > I make a use of multidimensional matrices. For example, I need to
extract
> > mean from one of the dimensions:
> >
> > % we have matrix data of size: 130 x 11 x 350 x 2
> > data = data - repmat(mean(data,3),[130 1 1 1]);
> >
> > In R project I managed to do that in a very pervarsive way:
> >
> > # mean(data,3) in R
> > base <- apply(data,c(2,3,4),mean)
> > # repmat(...,[130 1 1 1])
> > base <- rep(base,130)
> > dim(base) <- c(11,2,350,130)
> > base <- aperm(base,c(4,1,2,3))
> > # data = data - repmat
> > data <- data - base;
> >
> > Could you please show me a more elegant way of doing the same in R :)
> >
> >Thanks, Daniil.
> >
> >______________________________________________
> >R-help at 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
> >
> >
> >
> >
>