def mmul( self, other ):
        if other.dim==2: return Mat( map(self.mmul, other.tr()) ).tr()
        assert NPRE or self.cols == len(other)
        return Vec( map(other.dot, self) )
Find all shard states for given mapreduce.
dataset/ETHPy150Open sunlightlabs/clearspending/completeness/statlib/matfunc.py/Matrix.mmul--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/mapreduce/model.py/ShardState.find_by_mapreduce_state