[R] matlab style of storing arrays compared to R

Douglas Bates bates at stat.wisc.edu
Fri Nov 21 17:12:07 CET 2008


R uses column-major ordering of multidimensional arrays, as in
Fortran, unlike the row-major ordering of C multidimensional arrays.
This is because the numerical linear algebra code used in R is from
the Eispack, Linpack, BLAS, Lapack family of Fortran subroutine
packages.  Even when implementation languages other than Fortran are
used, the Fortran storage conventions prevail because they affect the
design of algorithms.

Matlab is based on the same code (Matlab began as an interactive
wrapper around Eispack and Linpack) and uses the same representation
of arrays.

On Fri, Nov 21, 2008 at 2:41 AM, Rainer M Krug <r.m.krug at gmail.com> wrote:
> Hi
>
> I am trying to figure out, if the matlab style of linear indexing of
> an array is the same as in R. i.e.
>
> when
>
> x <- array( 1:24, dim=c(2,3,4) )
> x[3]
>> 3
>
> and if the same is true in matlab, assuming that
> x[n1,n2,n3] in R returns the same as  y(n1,n2,n3) when  y is a matrix in matlab
>
> I found the following reference
> http://www.mathworks.com/access/helpdesk/help/techdoc/index.html?/access/helpdesk/help/techdoc/matlab_prog/f1-86528.html#f1-86846
>
> And it seems to be the same, but another source says it is different.
> Could somebody confirm, if it is the same?
>
> Thanks,
>
> Rainer
>
>
> --
> Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
> Biology, UCT), Dipl. Phys. (Germany)
>
> Centre of Excellence for Invasion Biology
> Faculty of Science
> Natural Sciences Building
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> University of Stellenbosch
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>
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