[R] Vectorization in a random order

Jeff Newmiller jdnewmil at dcn.davis.ca.us
Thu Nov 10 16:43:05 CET 2016

I think you answered your own question. For loops are not a boogeyman... poor memory management is.

Algorithms that are sensitive to evaluation sequence are often not very re-usable, and certainly not parallelizable. If you have a specific algorithm in mind, there may be some advice we can give you about optimization, but as it stands think you know how to get a working implementation. 
Sent from my phone. Please excuse my brevity.

On November 10, 2016 5:06:07 AM PST, Thomas Chesney <Thomas.Chesney at nottingham.ac.uk> wrote:
>Is there a way to use vectorization where the elements are evaluated in
>a random order?
>For instance, if the code is to be run on each row in a matrix of
>length nBuy the following will do the job
>for (b in sample(1:nBuy,nBuy, replace=FALSE)){
>apply(nBuyMat, 1, function(x))
>will be run I believe, in the same order each time (Row1, then Row2,
>then Row3 etc.)
>This is important for building agent based models (the classic
>explanation of this is probably Huberman & Glance's response to Nowak &
>May's 1992 Nature article - Evolutionary games and computer
>simulations, http://www.pnas.org/content/90/16/7716.abstract)
>Thank you,
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