VectorSimilarities

vectorSimilarities.py

class VectorSimilarities(MRJob):

    def steps(self):
        return [self.mr(self.input,
                         self.group_by_user_rating),
                self.mr(None, self.count_ratings_users_freq),
                self.mr(self.pairwise_items, self.calculate_similarity),
                self.mr(self.calculate_ranking, self.top_similar_items)
                ]

    def configure_options(self):
        super(VectorSimilarities, self).configure_options()
        self.add_passthrough_option(
            '--priorcount', dest='prior_count', default=10, type='int',
            help='PRIOR_COUNT: Parameter to regularize correlation')

        self.add_passthrough_option(
            '--priorcorrelation', dest='prior_correlation', default=0,
             type='int',
             help='PRIOR_CORRELATION: Parameter to regularize correlation')

        self.add_passthrough_option(
            '--minraters', dest='min_num_raters', default=3, type='int',
            help='the minimum number of raters')

        self.add_passthrough_option(
            '--maxraters', dest='max_num_raters', default=10000, type='int',
            help='the maximum number of raters')

        self.add_passthrough_option(
            '--minintersec', dest='min_intersection', default=0, type='int',
            help='the minimum intersection')

    def input(self, key, line):
        '''
        Subclasses should override this to define their own input
        '''
        raise NotImplementedError('Implement this in the subclass')

    ...