Find best and worst performers w.r.t. working time

This commit is contained in:
Maximilian Grundke
2018-02-20 21:25:15 +01:00
parent 06928340c9
commit 4c97faeec9
2 changed files with 57 additions and 18 deletions

View File

@ -5,8 +5,15 @@ namespace :detect_exercise_anomalies do
MIN_TIME_FACTOR = 0.1
MAX_TIME_FACTOR = 2
# Determines how many users are picked from the best/average/worst performers of each anomaly for feedback
NUMBER_OF_USERS_PER_CLASS = 10
# Determines margin below which user working times will be considered data errors (e.g. copy/paste solutions)
MIN_USER_WORKING_TIME = 0.0
# Cache exercise working times, because queries are expensive and values do not change between collections
WORKING_TIME_CACHE = {}
AVERAGE_WORKING_TIME_CACHE = {}
task :with_at_least, [:number_of_exercises, :number_of_solutions] => :environment do |task, args|
number_of_exercises = args[:number_of_exercises]
@ -23,7 +30,6 @@ namespace :detect_exercise_anomalies do
anomalies = find_anomalies(collection)
if anomalies.length > 0 and not collection.user.nil?
puts "\t\tAnomalies: #{anomalies}\n"
notify_collection_author(collection, anomalies)
notify_users(collection, anomalies)
reset_anomaly_detection_flag(collection)
@ -51,7 +57,7 @@ namespace :detect_exercise_anomalies do
working_times = {}
collection.exercises.each do |exercise|
puts "\t\t> #{exercise.title}"
working_times[exercise.id] = get_working_time(exercise)
working_times[exercise.id] = get_average_working_time(exercise)
end
average = working_times.values.reduce(:+) / working_times.size
working_times.select do |exercise_id, working_time|
@ -59,11 +65,26 @@ namespace :detect_exercise_anomalies do
end
end
def get_working_time(exercise)
def time_to_f(timestamp)
unless timestamp.nil?
timestamp = timestamp.split(':')
return timestamp[0].to_i * 60 * 60 + timestamp[1].to_i * 60 + timestamp[2].to_f
end
nil
end
def get_average_working_time(exercise)
unless AVERAGE_WORKING_TIME_CACHE.key?(exercise.id)
seconds = time_to_f exercise.average_working_time
AVERAGE_WORKING_TIME_CACHE[exercise.id] = seconds
end
AVERAGE_WORKING_TIME_CACHE[exercise.id]
end
def get_user_working_times(exercise)
unless WORKING_TIME_CACHE.key?(exercise.id)
avgwt = exercise.average_working_time.split(':')
seconds = avgwt[0].to_i * 60 * 60 + avgwt[1].to_i * 60 + avgwt[2].to_f
WORKING_TIME_CACHE[exercise.id] = seconds
exercise.retrieve_working_time_statistics
WORKING_TIME_CACHE[exercise.id] = exercise.working_time_statistics
end
WORKING_TIME_CACHE[exercise.id]
end
@ -76,22 +97,39 @@ namespace :detect_exercise_anomalies do
def notify_users(collection, anomalies)
puts "\t\tSending E-Mails to best and worst performing users of each anomaly..."
anomalies.each do |exercise_id, average_working_time|
submissions = Exercise.find(exercise_id)
.last_submission_per_user
.where('score is not null')
.order(:score)
best_performers = submissions.first(10).to_a.map do |item|
item.user_id
puts "\t\tAnomaly in exercise #{exercise_id} (avg: #{average_working_time} seconds):"
exercise = Exercise.find(exercise_id)
submissions = exercise.last_submission_per_user
users = performers_by_score(submissions, NUMBER_OF_USERS_PER_CLASS)
users = users.merge(performers_by_time(exercise, NUMBER_OF_USERS_PER_CLASS)) {|key, this, other| this + other}
[:best, :average, :worst].each do |sym|
segment = users[sym].uniq
puts "\t\t\t#{sym.to_s} performers: #{segment}"
end
worst_performers = submissions.last(10).to_a.map do |item|
item.user_id
end
puts "\t\tAnomaly in exercise #{exercise_id}:"
puts "\t\t\tbest performers: #{best_performers}"
puts "\t\t\tworst performers: #{worst_performers}"
end
end
def performers_by_score(submissions, n)
submissions = submissions.where('score is not null').order(:score)
best_performers = submissions.first(n).to_a.map {|item| item.user_id}
worst_performers = submissions.last(n).to_a.map {|item| item.user_id}
return {:best => best_performers, :average => [], :worst => worst_performers}
end
def performers_by_time(exercise, n)
working_times = get_user_working_times(exercise).values.map do |item|
{user_id: item['user_id'], time: time_to_f(item['working_time'])}
end
working_times.reject! {|item| item[:time].nil? or item[:time] <= MIN_USER_WORKING_TIME}
working_times.sort_by! {|item| item[:time]}
working_times.map! {|item| item[:user_id].to_i}
return {:best => working_times.first(n), :average => [], :worst => working_times.last(n)}
end
def reset_anomaly_detection_flag(collection)
puts "\t\tResetting flag..."
collection.use_anomaly_detection = false