The EnsembleGravity founded the Grand Prize Team (GPT) with our former collaborative team, Dinosaur Planet, in January 2009 in order to collect top seated teams for a collaborative effort to win the Grand Prize. The team started with a 9.04% improvement over Cinematch, Netflix's own recommender solution. Soon after, due to the very useful contribution of other teams, GPT became a major player for the final period of the Netflix Prize contest. The GPT team leader, Gábor Takács, founder of Gravity, was interviewed by a Netflix competitor, when GPT reached the second place of the contest with 9.64 % improvement, just 0.01% behind the leading team.
On June 26, when with a joint effort of 3 other teams outside of GPT (Pragmatic Theory, BigChaos, and BellKor) - BellKor's Pragmatic Chaos (BPC) - passed the magic 10% limit (namely they got to 10.05%), and the last 30 days of the competition has started, we initiated an even more collaborative work within GPT. We created an internal forum for directing the work and discussion of the many team members. As a result, we reached 9.91% within a few days. At the same time more collaborative work has been started among the top contenders of the contest, created joined teams based on the pattern of GPT. With only about 2 weeks remaining from the contest we started to negotiate with the biggest of such conglomerated team, Vandelay Industries!, and we created to a merged team with the name The Ensemble, also leaded by Gábor Takács from Gravity. It turned out with the help of some noisified submissions that The Ensemble can get really close to or even overtake BPC. The Ensemble submitted the first submission with only 1 day to go from the competition, which led the team to the top of the leaderboard with 10.09% improvement - this overtook BPC with a bare 0.01 % since they improved during these 29 days to 10.08 %. The final day was really memorable. Both teams worked with extreme efforts to tweak out some more results from their algorithms. And both succeeded. With 25 minutes to go, a BPC submission (10.09 %) tied up with The Ensemble, but only 4 minutes to go, we could get an even better predictor, that remained on the top of the leaderboard: 10.10%.
However, the contest did not end with the final countdown. Netflix will announce the winner after validating the teams’ submissions, poring over the submitted code, design documents and other materials. This process can run for months. Whatever will be the final result of the contest, Gravity, as a founder of GPT and the member of The Ensemble, is proud to have participated with a valuable contribution in the team that ended up on the top of the leaderboard of the most exciting machine learning contest ever.
