[R] R matrices in memory
bates at stat.wisc.edu
Fri Jul 18 01:15:29 CEST 2003
Francisco J Molina <fjmolina at lbl.gov> writes:
> Acording to the documentation in gsl
> "The physical row dimension tda, or trailing dimension, specifies the size
> of a row of the matrix as laid out in memory"
I think you may have problems here. Arrays in R are stored in
column-major ordering, as in Fortran. In other words, the elements of
a row of a matrix are not adjacent in memory so "the size of a row of
the matrix as laid out in memory" is not meaningful.
For R matrices the elements of columns are adjacent in memory.
You may need to write conversion routines to copy the contents of the
R matrix into the form that GSL expects.
> I think that if I pass a matrix to C++ through .C as single ( or.double ),
> that is,
> .C ( as.single ( matrix ))
> then the tda is simply the number of elements of that matrix.
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