NTDS'17 assignment 1: Feedback

Effrosyni Simou, EPFL LTS4

For the correction of the first assignment the following grading scheme was followed:

1) find_connections function -> 20 points

Common mistakes included:

• not using the Cursor object to iterate through pages
• not accounting for protected users (if this was added in the network collection, points were removed only partially)

2) collection of the Twitter network -> 30 points

Common mistakes included:

• not handling protected users
• not gathering different nodes in the first_nodes and the second_nodes list (only partial points extracted if the removal of duplicates was done efficiently in the next step)
• adding protected users in the collected network and trying to recover their connections (not the best solution)

3) finding the total number of nodes (removing duplicates) -> 5 points

Common mistakes included:

• Not removing at all existing duplicates
• Removing only duplicates from first_nodes and second_nodes but not removing the duplicates of the nodes that were present in both of these lists

4) finding all of the inner connections between the collected nodes -> 20 points

Common mistakes included:

• Simply adding the symmetric connections of the ones you had already found.
• Only finding the inner connections between second nodes (remember that inner connections can exist also between two first nodes for instance)

5) construct adjacency matrix W from the dictionary network -> 10 points

Almost everyone did perfectly in this part.

6) Question 1 -> 1 point

Good answers from most in this part.

7) Plot of adjacency matrix W -> 1 point

Everyone did perfectly in this part.

8) Question 2 -> 3 points

Almost everyone did perfectly in this part.

9) Plot of degree distribution -> 1 point

OK answers from most at this part.

10) Question 3 -> 3 points

OK answers from most at this part.

11) Average degree -> 1 point

Everyone did perfectly in this part.

12) Question 4 -> 3 points

Common mistake:

• Some people said that the diameter was 2.

13) Network pruning -> 2 points

Almost everyone did perfectly in this part.

Overall, very good job everyone! Keep up with the good work :)