1. A non-transitory storage medium having stored instructions which, when executed by a processor, cause the processor to perform actions with regard to a dataset having a plurality of dataset elements and which is operably accessible to the processor, each of the dataset elements corresponding to a different document and each of the documents having one or more characteristics, the actions comprising: creating an n-tuple feature vector for each dataset element of the plurality of dataset elements, wherein each component of the n-tuple feature vector correlates to a specific characteristic of the corresponding dataset element; creating an m-tuple search vector for each dataset element, wherein m is less than n, and wherein each of the m-tuple search vectors includes as its components (a) the norm of its corresponding n-tuple feature vector, (b) the component sum of its corresponding n-tuple feature vector, and (c) a set of random projections of its corresponding n-tuple feature vector; selecting one of the dataset elements of the plurality of dataset elements to be a target dataset element; for each dataset element of a selected number of the plurality of dataset elements, determining a corresponding distance between its corresponding m-tuple search vector and the m-tuple search vector of the target dataset element; forming a candidate set comprising those dataset elements of the selected number of the plurality of dataset elements that have a corresponding m-tuple search vector that is within a specified distance range of the m-tuple search vector of the target dataset element; for each of the dataset elements in the candidate set, determining a corresponding distance between its corresponding n-tuple feature vector and the n-tuple feature vector of the target dataset element; and forming a filtered set of dataset elements comprising those dataset elements of the candidate set that have a corresponding n-tuple feature vector that is within a specified distance range of the n-tuple feature vector of the target dataset element.