Enchanting Netflix Contest Final
5100 program teams from 185 countries took part in the purely geek competition Netflix Prize with the main prize of one million dollars.
The contest ended yesterday at 6:42:37 UTC, exactly 30 days after one of the applicants achieved the desired result (RMSE is less than 0.8563). The finish turned out to be truly enchanting: immediately after the first challenger, the second one appeared, a fierce struggle broke out between them. Literally in the last hours, applicants changed places several times with each other!
Many of us with excitement watched in real time the outcome of this fascinating competition. As a result, the winner from the second prize-winner was only 0.0001 points. The fate of a million dollars was decided only 4 minutes before the deadline - despite the fact that the competition lasted from October 2, 2006. Who said that math contests can't be dramatic?
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Netflix company is engaged in renting movies, both online and offline. The core of their business is Cinematch's unique recommendation system. She predicts which films a person might like based on his past ratings of other films. As it is known, the recommendation systems are the Grail for modern e-commerce applications.
According to the rules of the Netflix contest, a development team could qualify for the top prize of a million dollars, which can improve Cinematch efficiency by at least 10%. To set up competitive algorithms, a set of initial user data was published: these are 100 million ratings (from 1 to 5 points) for 18 thousand films from 480 thousand randomly selected users. To check the results, a set of pairs of users and movies was published, and the algorithm had to predict the estimates as accurately as possible, while calculating the average RMSE error (root mean squared error). It should have improved Cinematch algorithm score (0.9525) by at least 10%. That is, it was necessary to show 0.8572 or less.
The competition lasted almost three years. The developers showed all the best results, and in the end several teams of programmers decided to join forces and make a breakthrough. This is how the BellKor's Pragmatic Chaos team appeared, which, on June 26, 2009, finally managed to improve the result by the cherished 10.08%. According to the rules, after that the other participants had 30 days to improve the result. And competitors seized the chance. Less than 24 hours before the deadline, The Ensemble team improved the result to 10.09%.
Programmers from BellKor also did not sleep in the hat. Apparently, they were ready for this, and 24 minutes before the deadline, they posted a new application, with the result the same as that of a competitor.
But the team The Ensemble has prepared a "two-way". They responded literally twenty minutes later, that is, four (!) Minutes before the deadline, the result of 10.10%, and BellKor had no time left for corny.
Thus, the competition ended with the victory of The Ensemble team. After checking the results, they should receive their deserved million.
The contest ended yesterday at 6:42:37 UTC, exactly 30 days after one of the applicants achieved the desired result (RMSE is less than 0.8563). The finish turned out to be truly enchanting: immediately after the first challenger, the second one appeared, a fierce struggle broke out between them. Literally in the last hours, applicants changed places several times with each other!
Many of us with excitement watched in real time the outcome of this fascinating competition. As a result, the winner from the second prize-winner was only 0.0001 points. The fate of a million dollars was decided only 4 minutes before the deadline - despite the fact that the competition lasted from October 2, 2006. Who said that math contests can't be dramatic?
')
Netflix company is engaged in renting movies, both online and offline. The core of their business is Cinematch's unique recommendation system. She predicts which films a person might like based on his past ratings of other films. As it is known, the recommendation systems are the Grail for modern e-commerce applications.
According to the rules of the Netflix contest, a development team could qualify for the top prize of a million dollars, which can improve Cinematch efficiency by at least 10%. To set up competitive algorithms, a set of initial user data was published: these are 100 million ratings (from 1 to 5 points) for 18 thousand films from 480 thousand randomly selected users. To check the results, a set of pairs of users and movies was published, and the algorithm had to predict the estimates as accurately as possible, while calculating the average RMSE error (root mean squared error). It should have improved Cinematch algorithm score (0.9525) by at least 10%. That is, it was necessary to show 0.8572 or less.
The competition lasted almost three years. The developers showed all the best results, and in the end several teams of programmers decided to join forces and make a breakthrough. This is how the BellKor's Pragmatic Chaos team appeared, which, on June 26, 2009, finally managed to improve the result by the cherished 10.08%. According to the rules, after that the other participants had 30 days to improve the result. And competitors seized the chance. Less than 24 hours before the deadline, The Ensemble team improved the result to 10.09%.
Programmers from BellKor also did not sleep in the hat. Apparently, they were ready for this, and 24 minutes before the deadline, they posted a new application, with the result the same as that of a competitor.
But the team The Ensemble has prepared a "two-way". They responded literally twenty minutes later, that is, four (!) Minutes before the deadline, the result of 10.10%, and BellKor had no time left for corny.
Thus, the competition ended with the victory of The Ensemble team. After checking the results, they should receive their deserved million.
Source: https://habr.com/ru/post/65476/
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