373 lines
18 KiB
Python
373 lines
18 KiB
Python
import courseware.content_parser as content_parser
|
|
import courseware.modules
|
|
import logging
|
|
import random
|
|
import urllib
|
|
|
|
from collections import namedtuple
|
|
from django.conf import settings
|
|
from lxml import etree
|
|
from models import StudentModule
|
|
from student.models import UserProfile
|
|
|
|
log = logging.getLogger("mitx.courseware")
|
|
|
|
Score = namedtuple("Score", "earned possible weight graded section")
|
|
SectionPercentage = namedtuple("SectionPercentage", "percentage label summary")
|
|
|
|
|
|
class CourseGrader(object):
|
|
"""
|
|
A course grader takes the totaled scores for each graded section (that a student has
|
|
started) in the course. From these scores, the grader calculates an overall percentage
|
|
grade. The grader should also generate information about how that score was calculated,
|
|
to be displayed in graphs or charts.
|
|
|
|
A grader has one required method, grade(), which is passed a grade_sheet. The grade_sheet
|
|
contains scores for all graded section that the student has started. If a student has
|
|
a score of 0 for that section, it may be missing from the grade_sheet. The grade_sheet
|
|
is keyed by section format. Each value is a list of Score namedtuples for each section
|
|
that has the matching section format.
|
|
|
|
The grader outputs a dictionary with the following keys:
|
|
- percent: Contaisn a float value, which is the final percentage score for the student.
|
|
- section_breakdown: This is a list of dictionaries which provide details on sections
|
|
that were graded. These are used for display in a graph or chart. The format for a
|
|
section_breakdown dictionary is explained below.
|
|
- grade_breakdown: This is a list of dictionaries which provide details on the contributions
|
|
of the final percentage grade. This is a higher level breakdown, for when the grade is constructed
|
|
of a few very large sections (such as Homeworks, Labs, a Midterm, and a Final). The format for
|
|
a grade_breakdown is explained below. This section is optional.
|
|
|
|
A dictionary in the section_breakdown list has the following keys:
|
|
percent: A float percentage for the section.
|
|
label: A short string identifying the section. Preferably fixed-length. E.g. "HW 3".
|
|
detail: A string explanation of the score. E.g. "Homework 1 - Ohms Law - 83% (5/6)"
|
|
category: A string identifying the category. Items with the same category are grouped together
|
|
in the display (for example, by color).
|
|
prominent: A boolean value indicating that this section should be displayed as more prominent
|
|
than other items.
|
|
|
|
A dictionary in the grade_breakdown list has the following keys:
|
|
percent: A float percentage in the breakdown. All percents should add up to the final percentage.
|
|
detail: A string explanation of this breakdown. E.g. "Homework - 10% of a possible 15%"
|
|
category: A string identifying the category. Items with the same category are grouped together
|
|
in the display (for example, by color).
|
|
|
|
|
|
"""
|
|
def grade(self, grade_sheet):
|
|
raise NotImplementedError
|
|
|
|
class WeightedSubsectionsGrader(CourseGrader):
|
|
"""
|
|
This grader takes a list of tuples containing (grader, category_name, weight) and computes
|
|
a final grade by totalling the contribution of each sub grader and multiplying it by the
|
|
given weight. For example, the sections may be
|
|
[ (homeworkGrader, "Homework", 0.15), (labGrader, "Labs", 0.15), (midtermGrader, "Midterm", 0.30), (finalGrader, "Final", 0.40) ]
|
|
All items in section_breakdown for each subgrader will be combined. A grade_breakdown will be
|
|
composed using the score from each grader.
|
|
|
|
Note that the sum of the weights is not take into consideration. If the weights add up to
|
|
a value > 1, the student may end up with a percent > 100%. This allows for sections that
|
|
are extra credit.
|
|
"""
|
|
def __init__(self, sections):
|
|
self.sections = sections
|
|
|
|
def grade(self, grade_sheet):
|
|
total_percent = 0.0
|
|
section_breakdown = []
|
|
grade_breakdown = []
|
|
|
|
for subgrader, section_name, weight in self.sections:
|
|
subgrade_result = subgrader.grade(grade_sheet)
|
|
|
|
weightedPercent = subgrade_result['percent'] * weight
|
|
section_detail = "{0} = {1:.1%} of a possible {2:.0%}".format(section_name, weightedPercent, weight)
|
|
|
|
total_percent += weightedPercent
|
|
section_breakdown += subgrade_result['section_breakdown']
|
|
grade_breakdown.append( {'percent' : weightedPercent, 'detail' : section_detail, 'category' : section_name} )
|
|
|
|
return {'percent' : total_percent,
|
|
'section_breakdown' : section_breakdown,
|
|
'grade_breakdown' : grade_breakdown}
|
|
|
|
|
|
class SingleSectionGrader(CourseGrader):
|
|
"""
|
|
This grades a single section with the format section_format and the name section_name.
|
|
|
|
If the section_name is not appropriate for the short short_label or category, they each may
|
|
be specified individually.
|
|
"""
|
|
def __init__(self, section_format, section_name, short_label = None, category = None):
|
|
self.section_format = section_format
|
|
self.section_name = section_name
|
|
self.short_label = short_label or section_name
|
|
self.category = category or section_name
|
|
|
|
def grade(self, grade_sheet):
|
|
foundScore = None
|
|
if self.section_format in grade_sheet:
|
|
for score in grade_sheet[self.section_format]:
|
|
if score.section == self.section_name:
|
|
foundScore = score
|
|
break
|
|
|
|
if foundScore:
|
|
percent = foundScore.earned / float(foundScore.possible)
|
|
detail = "{name} - {percent:.0%} ({earned:.3n}/{possible:.3n})".format( name = self.section_name,
|
|
percent = percent,
|
|
earned = float(foundScore.earned),
|
|
possible = float(foundScore.possible))
|
|
|
|
else:
|
|
percent = 0.0
|
|
detail = "{name} - 0% (?/?)".format(name = self.section_name)
|
|
|
|
|
|
breakdown = [{'percent': percent, 'label': self.short_label, 'detail': detail, 'category': self.category, 'prominent': True}]
|
|
|
|
return {'percent' : percent,
|
|
'section_breakdown' : breakdown,
|
|
#No grade_breakdown here
|
|
}
|
|
|
|
class AssignmentFormatGrader(CourseGrader):
|
|
"""
|
|
Grades all sections specified in course_format with an equal weight. A specified
|
|
number of lowest scores can be dropped from the calculation. The minimum number of
|
|
sections in this format must be specified (even if those sections haven't been
|
|
written yet).
|
|
|
|
min_number defines how many assignments are expected throughout the course. Placeholder
|
|
scores (of 0) will be inserted if the number of matching sections in the course is < min_number.
|
|
If there number of matching sections in the course is > min_number, min_number will be ignored.
|
|
|
|
category should be presentable to the user, but may not appear. When the grade breakdown is
|
|
displayed, scores from the same category will be similar (for example, by color).
|
|
|
|
section_type is a string that is the type of a singular section. For example, for Labs it
|
|
would be "Lab". This defaults to be the same as category.
|
|
|
|
short_label is similar to section_type, but shorter. For example, for Homework it would be
|
|
"HW".
|
|
|
|
"""
|
|
def __init__(self, course_format, min_number, drop_count, category = None, section_type = None, short_label = None):
|
|
self.course_format = course_format
|
|
self.min_number = min_number
|
|
self.drop_count = drop_count
|
|
self.category = category or self.course_format
|
|
self.section_type = section_type or self.course_format
|
|
self.short_label = short_label or self.course_format
|
|
|
|
def grade(self, grade_sheet):
|
|
def totalWithDrops(breakdown, drop_count):
|
|
#create an array of tuples with (index, mark), sorted by mark['percent'] descending
|
|
sorted_breakdown = sorted( enumerate(breakdown), key=lambda x: -x[1]['percent'] )
|
|
# A list of the indices of the dropped scores
|
|
dropped_indices = []
|
|
if drop_count > 0:
|
|
dropped_indices = [x[0] for x in sorted_breakdown[-drop_count:]]
|
|
aggregate_score = 0
|
|
for index, mark in enumerate(breakdown):
|
|
if index not in dropped_indices:
|
|
aggregate_score += mark['percent']
|
|
|
|
if (len(breakdown) - drop_count > 0):
|
|
aggregate_score /= len(breakdown) - drop_count
|
|
|
|
return aggregate_score, dropped_indices
|
|
|
|
#Figure the homework scores
|
|
scores = grade_sheet.get(self.course_format, [])
|
|
breakdown = []
|
|
for i in range( max(self.min_number, len(scores)) ):
|
|
if i < len(scores):
|
|
percentage = scores[i].earned / float(scores[i].possible)
|
|
summary = "{section_type} {index} - {name} - {percent:.0%} ({earned:.3n}/{possible:.3n})".format(index = i+1,
|
|
section_type = self.section_type,
|
|
name = scores[i].section,
|
|
percent = percentage,
|
|
earned = float(scores[i].earned),
|
|
possible = float(scores[i].possible) )
|
|
else:
|
|
percentage = 0
|
|
summary = "{section_type} {index} Unreleased - 0% (?/?)".format(index = i+1, section_type = self.section_type)
|
|
|
|
if settings.GENERATE_PROFILE_SCORES:
|
|
points_possible = random.randrange(10, 50)
|
|
points_earned = random.randrange(5, points_possible)
|
|
percentage = points_earned / float(points_possible)
|
|
summary = "{section_type} {index} - {name} - {percent:.0%} ({earned:.3n}/{possible:.3n})".format(index = i+1,
|
|
section_type = self.section_type,
|
|
name = "Randomly Generated",
|
|
percent = percentage,
|
|
earned = points_earned,
|
|
possible = points_possible )
|
|
|
|
short_label = "{short_label} {index:02d}".format(index = i+1, short_label = self.short_label)
|
|
|
|
breakdown.append( {'percent': percentage, 'label': short_label, 'detail': summary, 'category': self.category} )
|
|
|
|
total_percent, dropped_indices = totalWithDrops(breakdown, self.drop_count)
|
|
|
|
for dropped_index in dropped_indices:
|
|
breakdown[dropped_index]['mark'] = {'detail': "The lowest {drop_count} {section_type} scores are dropped.".format(drop_count = self.drop_count, section_type=self.section_type) }
|
|
|
|
|
|
total_detail = "{section_type} Average = {percent:.0%}".format(percent = total_percent, section_type = self.section_type)
|
|
total_label = "{short_label} Avg".format(short_label = self.short_label)
|
|
breakdown.append( {'percent': total_percent, 'label': total_label, 'detail': total_detail, 'category': self.category, 'prominent': True} )
|
|
|
|
|
|
return {'percent' : total_percent,
|
|
'section_breakdown' : breakdown,
|
|
#No grade_breakdown here
|
|
}
|
|
|
|
def get_score(user, problem, cache):
|
|
## HACK: assumes max score is fixed per problem
|
|
id = problem.get('id')
|
|
correct = 0
|
|
|
|
# If the ID is not in the cache, add the item
|
|
if id not in cache:
|
|
module = StudentModule(module_type = 'problem', # TODO: Move into StudentModule.__init__?
|
|
module_id = id,
|
|
student = user,
|
|
state = None,
|
|
grade = 0,
|
|
max_grade = None,
|
|
done = 'i')
|
|
cache[id] = module
|
|
|
|
# Grab the # correct from cache
|
|
if id in cache:
|
|
response = cache[id]
|
|
if response.grade!=None:
|
|
correct=response.grade
|
|
|
|
# Grab max grade from cache, or if it doesn't exist, compute and save to DB
|
|
if id in cache and response.max_grade != None:
|
|
total = response.max_grade
|
|
else:
|
|
total=courseware.modules.capa_module.Module(etree.tostring(problem), "id").max_score()
|
|
response.max_grade = total
|
|
response.save()
|
|
|
|
return (correct, total)
|
|
|
|
def grade_sheet(student):
|
|
"""
|
|
This pulls a summary of all problems in the course. It returns a dictionary with two datastructures:
|
|
|
|
- courseware_summary is a summary of all sections with problems in the course. It is organized as an array of chapters,
|
|
each containing an array of sections, each containing an array of scores. This contains information for graded and ungraded
|
|
problems, and is good for displaying a course summary with due dates, etc.
|
|
|
|
- grade_summary is a summary of how the final grade breaks down. It is an array of "sections". Each section can either be
|
|
a conglomerate of scores (like labs or homeworks) which has subscores and a totalscore, or a section can be all from one assignment
|
|
(such as a midterm or final) and only has a totalscore. Each section has a weight that shows how it contributes to the total grade.
|
|
"""
|
|
dom=content_parser.course_file(student)
|
|
course = dom.xpath('//course/@name')[0]
|
|
xmlChapters = dom.xpath('//course[@name=$course]/chapter', course=course)
|
|
|
|
responses=StudentModule.objects.filter(student=student)
|
|
response_by_id = {}
|
|
for response in responses:
|
|
response_by_id[response.module_id] = response
|
|
|
|
|
|
|
|
totaled_scores = {}
|
|
chapters=[]
|
|
for c in xmlChapters:
|
|
sections = []
|
|
chname=c.get('name')
|
|
|
|
|
|
for s in dom.xpath('//course[@name=$course]/chapter[@name=$chname]/section',
|
|
course=course, chname=chname):
|
|
problems=dom.xpath('//course[@name=$course]/chapter[@name=$chname]/section[@name=$section]//problem',
|
|
course=course, chname=chname, section=s.get('name'))
|
|
|
|
graded = True if s.get('graded') == "true" else False
|
|
scores=[]
|
|
if len(problems)>0:
|
|
for p in problems:
|
|
(correct,total) = get_score(student, p, response_by_id)
|
|
|
|
if settings.GENERATE_PROFILE_SCORES:
|
|
if total > 1:
|
|
correct = random.randrange( max(total-2, 1) , total + 1 )
|
|
else:
|
|
correct = total
|
|
scores.append( Score(int(correct),total, float(p.get("weight", total)), graded, p.get("name")) )
|
|
|
|
section_total, graded_total = aggregate_scores(scores, s.get("name"), s.get("weight", 1))
|
|
#Add the graded total to totaled_scores
|
|
format = s.get('format') if s.get('format') else ""
|
|
subtitle = s.get('subtitle') if s.get('subtitle') else format
|
|
if format and graded_total[1] > 0:
|
|
format_scores = totaled_scores.get(format, [])
|
|
format_scores.append( graded_total )
|
|
totaled_scores[ format ] = format_scores
|
|
|
|
section_score={'section':s.get("name"),
|
|
'scores':scores,
|
|
'section_total' : section_total,
|
|
'format' : format,
|
|
'subtitle' : subtitle,
|
|
'due' : s.get("due") or "",
|
|
'graded' : graded,
|
|
}
|
|
sections.append(section_score)
|
|
|
|
chapters.append({'course':course,
|
|
'chapter' : c.get("name"),
|
|
'sections' : sections,})
|
|
|
|
#TODO: This grader declaration should live in the data repository. It is only here now to get it working
|
|
hwGrader = AssignmentFormatGrader("Homework", 12, 2, short_label = "HW")
|
|
labGrader = AssignmentFormatGrader("Lab", 12, 2, category = "Labs")
|
|
midtermGrader = SingleSectionGrader("Midterm", "Midterm Exam", short_label = "Midterm")
|
|
finalGrader = SingleSectionGrader("Examination", "Final Exam", short_label = "Final")
|
|
|
|
grader = WeightedSubsectionsGrader( [(hwGrader, hwGrader.category, 0.15), (labGrader, labGrader.category, 0.15),
|
|
(midtermGrader, midtermGrader.category, 0.30), (finalGrader, finalGrader.category, 0.40)] )
|
|
|
|
grade_summary = grader.grade(totaled_scores)
|
|
|
|
return {'courseware_summary' : chapters,
|
|
'grade_summary' : grade_summary}
|
|
|
|
def aggregate_scores(scores, section_name = "summary", section_weight = 1):
|
|
#TODO: What does a possible score of zero mean? We need to think what extra credit is
|
|
scores = filter( lambda score: score.possible > 0, scores )
|
|
|
|
total_correct_graded = sum((score.earned*1.0/score.possible)*score.weight for score in scores if score.graded)
|
|
total_possible_graded = sum(score.weight for score in scores if score.graded)
|
|
|
|
total_correct = sum((score.earned*1.0/score.possible)*score.weight for score in scores)
|
|
total_possible = sum(score.weight for score in scores)
|
|
|
|
#regardless of whether or not it is graded
|
|
all_total = Score(total_correct,
|
|
total_possible,
|
|
section_weight,
|
|
False,
|
|
section_name)
|
|
#selecting only graded things
|
|
graded_total = Score(total_correct_graded,
|
|
total_possible_graded,
|
|
section_weight,
|
|
True,
|
|
section_name)
|
|
|
|
return all_total, graded_total
|