[R] Array multiplication

[Peter Dalgaard BSA]

Murray Jorgensen <maj at stats.waikato.ac.nz> writes:

> I wanted to do some timings, but system.time() seems not to work on
> compound statements.
> 	
> system.time({
> for (i in 1:n) {
>    for (k in 1:d) {
>      for (j in 1:m) {
>        lamb.star[i,k] = lamb.star[i,k] + lambda[i,j,k]*zed[i,j]
>      }
>    }
> }
> )}
> 
> gives a syntax error.  I suppose there is a much smarter way to do
> this sort of stuff and that somebody will show me?

Ending that with "})" instead should get rid of the syntax error....

There is a "tensor" package on CRAN that would seem to be designed for
these types of operations.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
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