Very Slow Gower Similarity Function

On 18 Apr 2005, at 19:10, Tyler Smith wrote:

Hello,

I am a relatively new user of R. I have written a basic function to 
calculate
the Gower similarity function. I was motivated to do so partly as an 
excercise
in learning R, and partly because the existing option (vegdist in the 
vegan
package) does not accept missing values.

Speed is the reason to use C instead of R. It should be easy, almost 
trivial, to modify the vegdist.c  so that it handles missing values. I 
guess this handling means ignoring the value pair if one of the values 
is missing -- which is not so gentle to the metric properties so dear 
to Gower. Package vegan is designed for ecological community data 
which generally do not have missing values (except in environmental 
data), but contributions are welcome.