Patent ID: 8332411

Claim:
A method comprising the following computer-executable acts: at a computing device that comprises a processor and memory, receiving estimated gradients of a cost with respect to a plurality of training points, wherein the estimated gradients of the cost correspond to a first ranker; causing the processor to train a second ranker based at least in part upon the received estimated gradients; and linearly combining the first ranker with the second ranker to generate a linear combination of the first ranker and the second ranker, wherein the linear combination of the first ranker and the second ranker is of the form s F =s 1 +ws 2 , wherein s F is a final score for a training point with respect to a query output by the linear combination, s 1 is a score for the training point with respect to the query output by the first ranker, s 2 is a score for the training point with respect to the query output by the second ranker, and w is a weight used to modify scores output by the second ranker, wherein w is computed to optimally linearly combine the second ranker with the first ranker with respect to an information retrieval metric method, and wherein computing w comprises: receiving first scores for a plurality of training points, wherein each training point in the plurality of training points is individually assigned a score by the first ranker; and receiving second scores for the plurality of training points, wherein each training point in the plurality of training points is individually assigned a score by the second ranker, wherein w is computed based at least in part upon the first scores and the second scores.