[R] fastest way to compute the squared Euclidean distance between two vectors in R

[Jason Liao]

I have a program which needs to compute squared Euclidean distance
between two vectors million of times, which the Rprof shows is the
bottleneck. I wondered if there is any faster way than my own simple
function

distance2 = function(x1, x2)
{
   temp = x1-x2
   sum(temp*temp)
}

I have searched the R-help archives and can not find anything except
when the arguments are matrices. Thanks for any lead.

Jason

Jason Liao, http://www.geocities.com/jg_liao    
Associate Professor of Biostatistics
Drexel University School of Public Health
1505 Race Street, Mail Stop 1033
Bellet Building, 6th Floor
Philadelphia, PA   19102
phone 215-762-3934


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