[R] R badly lags matlab on performance?

[Wacek Kusnierczyk]

Ajay Shah wrote:
>> As for jit and Ra, that was immediate reaction too but I found that jit does
>> not help on your example.  But I concur fully with what Ben said --- use the
>> tool that is appropriate for the task at hand.  If your task is running for
>> loops, Matlab does it faster and you have Matlab, well then you should by all
>> means use Matlab.
>>     
>
> A good chunk of statistical computation involves loops. We are all
> happy R users. I was surprised to see that we are so far from matlab
> in the crucial dimension of performance.
>
>   

this list has a tradition of encouraging users to use apply&relatives
instead of for loops (and to use vectorised code instead of both).

compare the following for n = 10^6 and n = 10^7:

x = 1:n
system.time({for (i in 1:n) x[i] = x[i] + 1})

x = 1:n
system.time({x = sapply(x, `+`, 1)})


vQ