PS I noticed another optimization:
On Wed, Jan 27, 2010 at 11:32 AM, Sean Owen <sro...@gmail.com> wrote:
> while (currentKey != NULL && (currentKey == REMOVED || key != currentKey))
> {
can be
while (currentKey != NULL && key != currentKey) {
since key is not allowed to be the value REMOVED ever.
It is non-trivial since this line is probably executed billions of
times in a good solid run of a recommender.
