These computations use a Map Reduce object getting case-specific functions map and reduce.
The scripts friend_count.py and asymetric_friendships.py compute number of friends for each person and the assymetric relations (one-way friendship) respectively.
Using two sparse matrices stored as tuples (matrix_name, row, column, value), the goal of multiply.py is to output the result of the matrix multiplication in the same format.
From DNA sequences, unique_trim.py takes out the ten last elements and return only the unique sequences (no copy).
join.py builds a join between two tables.
word_count.py... well trivially counts the occurrence of words in all documents of a data base. inverted_index.py finds all documents containing each word.