[R] Multiple matrix multiplication with two 3-dimensional arrays

[Anupam Tyagi]

Sophie Baillargeon <Sophie.Baillargeon <at> mat.ulaval.ca> writes:


> Maybe I could use an "apply" or something but I 
> can't figure out how. I would have hoped that simply doing
> 
> array1%*%array2
> 
> would work, but it doesn’t


I think one of the issues is that algebra for N-Dimentional arrays are not well
defined. Think how would you define the above operartion on two 3x3x3 arrays. I
had seen a paper a couple of years ago in some math journal that had proposed an
algebra. I will be interested in knowing a reference to some source that defines
3-dimentional array algebra. Then perhaps it could be implemented in R.

I will also be interested in knowing what is the equivalent of "cell" array in
MATLAB in R---that is something that is equivalent to the "cell" functions in a
spreadsheet---sometimes this can be useful.

Anupam.