10. The one or more non-transitory computer readable media of claim 9 , wherein the operations further comprise generating respective classifiers for one or more labels based on the buckets in the first lower-dimensional space and in the second lower-dimensional space, wherein a classifier maps a feature to a label.
10. The one or more non-transitory computer readable media of claim 9 , wherein the operations further comprise generating respective classifiers for one or more labels based on the buckets in the first lower-dimensional space and in the second lower-dimensional space, wherein a classifier maps a feature to a label. 11. The one or more non-transitory computer readable media of claim 10 , wherein the operations further comprise: selecting optimal buckets that are associated with a first label; and training classifiers for the first label based on the selected optimal buckets that are associated with the first label.