def test_all_students_paired_up_with_even_amount_of_students(
self, num_students):
teams = constants.STUDENTS[:num_students]
allocations = pairwise.generate_review_allocations(teams,
num_reviews=1)
assert len(allocations) == num_students
for review_team, reviewed_team in allocations:
expected_counter_review = plug.ReviewAllocation(
review_team=reviewed_team, reviewed_team=review_team)
assert allocations.index(expected_counter_review) >= 0
def generate_review_allocations(
teams: List[plug.StudentTeam], num_reviews: int = 1
) -> List[plug.ReviewAllocation]:
"""Generate peer review allocations such that if team_a reviews team_b,
then team_b reviews team_a, and no others!
The ``num_reviews`` argument is ignored by this plugin.
Args:
teams: Student teams for which to allocate reviews.
num_reviews: Ignored by this plugin.
Returns:
A list of allocations that
"""
teams = list(teams)
if num_reviews != 1:
plug.log.warning(
f"num_reviews specified to {num_reviews}, but in pairwise assignment "
f"num_reviews is ignored"
)
if len(teams) < 2:
raise ValueError(
f"there must be at least 2 teams for peer review, "
f"but {len(teams)} were provided"
)
random.shuffle(teams)
groups = [(teams[i - 1], teams[i]) for i in range(1, len(teams), 2)]
# odd number of teams necessitates 3 teams in last group
last_review_group = (
(*groups[-1], teams[-1]) if len(teams) % 2 else groups[-1]
)
finalized_groups = [*groups[:-1], last_review_group]
allocations = []
for group in finalized_groups:
for i, review_team in enumerate(group):
reviewed_team = group[(i + 1) % len(group)]
allocations.append(
plug.ReviewAllocation(
review_team=review_team, reviewed_team=reviewed_team
)
)
return allocations
def generate_review_allocations(
teams: List[plug.StudentTeam], num_reviews: int
) -> List[plug.ReviewAllocation]:
if num_reviews >= len(teams):
raise ValueError("num_reviews must be less than len(teams)")
if num_reviews <= 0:
raise ValueError("num_reviews must be greater than 0")
if len(teams) < 2:
raise ValueError(
f"there must be at least 2 teams for peer review, "
f"but {len(teams)} were provided"
)
random.shuffle(teams)
# create a list of lists, where each non-first list is a left-shifted
# version of the previous list (lists wrap around)
# e.g. for teams [4, 3, 1] and num_reviews = 2, the result is
# allocations = [[4, 3, 1], [3, 1, 4], [1, 4, 3]] and means that
# student 4 gets reviewed by 3 and 1, 3 by 1 and 4 etc.
allocations = [teams]
for _ in range(num_reviews):
next_reviewers = list(allocations[-1])
next_reviewers.append(next_reviewers.pop(0)) # shift list left
allocations.append(next_reviewers)
def merge_teams(teams):
members = list(
itertools.chain.from_iterable([team.members for team in teams])
)
return plug.StudentTeam(members=members)
transposed_allocations = zip(*allocations)
review_allocations = [
plug.ReviewAllocation(
review_team=merge_teams(reviewers), reviewed_team=reviewed_team
)
for reviewed_team, *reviewers in transposed_allocations
]
return review_allocations