This is not entirely true in R:

Details:

     ‘proc.time’ returns five elements for backwards compatibility, but
     its ‘print’ method prints a named vector of length 3.  The first
     two entries are the total user and system CPU times of the current
     R process and any child processes on which it has waited, and the
     third entry is the ‘real’ elapsed time since the process was
     started.


On Wednesday, July 6, 2016 at 5:11:04 PM UTC+2, Michael Borregaard wrote:
>
> I am not seeing your speed-up in R? elapsed is less time, but user 
> significantly more, and it is the sum that counts.
> When executing in parallel the language needs to copy the data to the 
> workers. If the matrices are large, that takes longer than the speedup of 
> the parallel execution. See what happens with a smaller matrix and then 
> repeating the operation on the workers.
>
>

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