On Sat, Sep 14, 2013 at 1:56 PM, Roger Hui <[email protected]> wrote: > I failed to do an example with 1e7 members. The expected number of friends > is 75 per the Dunbar requirement. For n members, the size of s is > (75*n),2. On J64, integers are 8 bytes each, so the total number of bytes > is 8**/(75*n),2 and for n=1e7 equates to 12 GB.
Note also that the dunbar requirement in this thread is different from the dunbar number expressed at the wikipedia link (150 there was the average and expected averages were something in the range of 100-230 (and I'm not going to verify those numbers because (a) my mouse is acting up, and (b) the reasoning behind them was just too silly for me to make sense of)). That said, note that we have similarly structured information available in social networks (facebook graph, for example, but there are others). So hypothetically speaking, we could play with that data and see how similar those averages were to the dunbar averages. But, to do this, we'd undoubtably need greater than 12GB to represent the data. (I wonder if we have enough interest to put together enough of a community to implement J for infrastructures such as hadoop?) But note also that these toy problems - real problems at that scale are probably biological (or pornographic?) in character. (Genome project, was a recent example I noticed.) Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
