378 lines
16 KiB
Python
378 lines
16 KiB
Python
# Compute grades using real division, with no integer truncation
|
|
from __future__ import division
|
|
|
|
import random
|
|
import logging
|
|
|
|
from collections import defaultdict
|
|
from django.conf import settings
|
|
from django.contrib.auth.models import User
|
|
|
|
from models import StudentModuleCache
|
|
from module_render import get_module, get_instance_module
|
|
from xmodule import graders
|
|
from xmodule.capa_module import CapaModule
|
|
from xmodule.course_module import CourseDescriptor
|
|
from xmodule.graders import Score
|
|
from models import StudentModule
|
|
|
|
log = logging.getLogger("mitx.courseware")
|
|
|
|
def yield_module_descendents(module):
|
|
stack = module.get_display_items()
|
|
stack.reverse()
|
|
|
|
while len(stack) > 0:
|
|
next_module = stack.pop()
|
|
stack.extend( next_module.get_display_items() )
|
|
yield next_module
|
|
|
|
def yield_dynamic_descriptor_descendents(descriptor, module_creator):
|
|
"""
|
|
This returns all of the descendants of a descriptor. If the descriptor
|
|
has dynamic children, the module will be created using module_creator
|
|
and the children (as descriptors) of that module will be returned.
|
|
"""
|
|
def get_dynamic_descriptor_children(descriptor):
|
|
if descriptor.has_dynamic_children():
|
|
module = module_creator(descriptor)
|
|
child_locations = module.get_children_locations()
|
|
return [descriptor.system.load_item(child_location) for child_location in child_locations ]
|
|
else:
|
|
return descriptor.get_children()
|
|
|
|
|
|
stack = [descriptor]
|
|
|
|
while len(stack) > 0:
|
|
next_descriptor = stack.pop()
|
|
stack.extend( get_dynamic_descriptor_children(next_descriptor) )
|
|
yield next_descriptor
|
|
|
|
|
|
def yield_problems(request, course, student):
|
|
"""
|
|
Return an iterator over capa_modules that this student has
|
|
potentially answered. (all that student has answered will definitely be in
|
|
the list, but there may be others as well).
|
|
"""
|
|
grading_context = course.grading_context
|
|
student_module_cache = StudentModuleCache(course.id, student, grading_context['all_descriptors'])
|
|
|
|
for section_format, sections in grading_context['graded_sections'].iteritems():
|
|
for section in sections:
|
|
|
|
section_descriptor = section['section_descriptor']
|
|
|
|
# If the student hasn't seen a single problem in the section, skip it.
|
|
skip = True
|
|
for moduledescriptor in section['xmoduledescriptors']:
|
|
if student_module_cache.lookup(
|
|
course.id, moduledescriptor.category, moduledescriptor.location.url()):
|
|
skip = False
|
|
break
|
|
|
|
if skip:
|
|
continue
|
|
|
|
section_module = get_module(student, request,
|
|
section_descriptor.location, student_module_cache,
|
|
course.id)
|
|
if section_module is None:
|
|
# student doesn't have access to this module, or something else
|
|
# went wrong.
|
|
# log.debug("couldn't get module for student {0} for section location {1}"
|
|
# .format(student.username, section_descriptor.location))
|
|
continue
|
|
|
|
for problem in yield_module_descendents(section_module):
|
|
if isinstance(problem, CapaModule):
|
|
yield problem
|
|
|
|
def answer_distributions(request, course):
|
|
"""
|
|
Given a course_descriptor, compute frequencies of answers for each problem:
|
|
|
|
Format is:
|
|
|
|
dict: (problem url_name, problem display_name, problem_id) -> (dict : answer -> count)
|
|
|
|
TODO (vshnayder): this is currently doing a full linear pass through all
|
|
students and all problems. This will be just a little slow.
|
|
"""
|
|
|
|
counts = defaultdict(lambda: defaultdict(int))
|
|
|
|
enrolled_students = User.objects.filter(courseenrollment__course_id=course.id)
|
|
|
|
for student in enrolled_students:
|
|
for capa_module in yield_problems(request, course, student):
|
|
for problem_id in capa_module.lcp.student_answers:
|
|
# Answer can be a list or some other unhashable element. Convert to string.
|
|
answer = str(capa_module.lcp.student_answers[problem_id])
|
|
key = (capa_module.url_name, capa_module.display_name, problem_id)
|
|
counts[key][answer] += 1
|
|
|
|
return counts
|
|
|
|
|
|
def grade(student, request, course, student_module_cache=None, keep_raw_scores=False):
|
|
"""
|
|
This grades a student as quickly as possible. It retuns the
|
|
output from the course grader, augmented with the final letter
|
|
grade. The keys in the output are:
|
|
|
|
course: a CourseDescriptor
|
|
|
|
- grade : A final letter grade.
|
|
- percent : The final percent for the class (rounded up).
|
|
- section_breakdown : A breakdown of each section that makes
|
|
up the grade. (For display)
|
|
- grade_breakdown : A breakdown of the major components that
|
|
make up the final grade. (For display)
|
|
- keep_raw_scores : if True, then value for key 'raw_scores' contains scores for every graded module
|
|
|
|
More information on the format is in the docstring for CourseGrader.
|
|
"""
|
|
|
|
grading_context = course.grading_context
|
|
raw_scores = []
|
|
|
|
if student_module_cache == None:
|
|
student_module_cache = StudentModuleCache(course.id, student, grading_context['all_descriptors'])
|
|
|
|
totaled_scores = {}
|
|
# This next complicated loop is just to collect the totaled_scores, which is
|
|
# passed to the grader
|
|
for section_format, sections in grading_context['graded_sections'].iteritems():
|
|
format_scores = []
|
|
for section in sections:
|
|
section_descriptor = section['section_descriptor']
|
|
section_name = section_descriptor.metadata.get('display_name')
|
|
|
|
should_grade_section = False
|
|
# If we haven't seen a single problem in the section, we don't have to grade it at all! We can assume 0%
|
|
for moduledescriptor in section['xmoduledescriptors']:
|
|
if student_module_cache.lookup(
|
|
course.id, moduledescriptor.category, moduledescriptor.location.url()):
|
|
should_grade_section = True
|
|
break
|
|
|
|
if should_grade_section:
|
|
scores = []
|
|
|
|
def create_module(descriptor):
|
|
# TODO: We need the request to pass into here. If we could forgo that, our arguments
|
|
# would be simpler
|
|
return get_module(student, request, descriptor.location,
|
|
student_module_cache, course.id)
|
|
|
|
for module_descriptor in yield_dynamic_descriptor_descendents(section_descriptor, create_module):
|
|
|
|
(correct, total) = get_score(course.id, student, module_descriptor, create_module, student_module_cache)
|
|
if correct is None and total is None:
|
|
continue
|
|
|
|
if settings.GENERATE_PROFILE_SCORES: # for debugging!
|
|
if total > 1:
|
|
correct = random.randrange(max(total - 2, 1), total + 1)
|
|
else:
|
|
correct = total
|
|
|
|
graded = module_descriptor.metadata.get("graded", False)
|
|
if not total > 0:
|
|
#We simply cannot grade a problem that is 12/0, because we might need it as a percentage
|
|
graded = False
|
|
|
|
scores.append(Score(correct, total, graded, module_descriptor.metadata.get('display_name')))
|
|
|
|
section_total, graded_total = graders.aggregate_scores(scores, section_name)
|
|
if keep_raw_scores:
|
|
raw_scores += scores
|
|
else:
|
|
section_total = Score(0.0, 1.0, False, section_name)
|
|
graded_total = Score(0.0, 1.0, True, section_name)
|
|
|
|
#Add the graded total to totaled_scores
|
|
if graded_total.possible > 0:
|
|
format_scores.append(graded_total)
|
|
else:
|
|
log.exception("Unable to grade a section with a total possible score of zero. " + str(section_descriptor.location))
|
|
|
|
totaled_scores[section_format] = format_scores
|
|
|
|
grade_summary = course.grader.grade(totaled_scores, generate_random_scores=settings.GENERATE_PROFILE_SCORES)
|
|
|
|
# We round the grade here, to make sure that the grade is an whole percentage and
|
|
# doesn't get displayed differently than it gets grades
|
|
grade_summary['percent'] = round(grade_summary['percent'] * 100 + 0.05) / 100
|
|
|
|
letter_grade = grade_for_percentage(course.grade_cutoffs, grade_summary['percent'])
|
|
grade_summary['grade'] = letter_grade
|
|
grade_summary['totaled_scores'] = totaled_scores # make this available, eg for instructor download & debugging
|
|
if keep_raw_scores:
|
|
grade_summary['raw_scores'] = raw_scores # way to get all RAW scores out to instructor
|
|
# so grader can be double-checked
|
|
return grade_summary
|
|
|
|
def grade_for_percentage(grade_cutoffs, percentage):
|
|
"""
|
|
Returns a letter grade as defined in grading_policy (e.g. 'A' 'B' 'C' for 6.002x) or None.
|
|
|
|
Arguments
|
|
- grade_cutoffs is a dictionary mapping a grade to the lowest
|
|
possible percentage to earn that grade.
|
|
- percentage is the final percent across all problems in a course
|
|
"""
|
|
|
|
letter_grade = None
|
|
|
|
# Possible grades, sorted in descending order of score
|
|
descending_grades = sorted(grade_cutoffs, key=lambda x: grade_cutoffs[x], reverse=True)
|
|
for possible_grade in descending_grades:
|
|
if percentage >= grade_cutoffs[possible_grade]:
|
|
letter_grade = possible_grade
|
|
break
|
|
|
|
return letter_grade
|
|
|
|
|
|
# TODO: This method is not very good. It was written in the old course style and
|
|
# then converted over and performance is not good. Once the progress page is redesigned
|
|
# to not have the progress summary this method should be deleted (so it won't be copied).
|
|
def progress_summary(student, request, course, student_module_cache):
|
|
"""
|
|
This pulls a summary of all problems in the course.
|
|
|
|
Returns
|
|
- 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.
|
|
|
|
Arguments:
|
|
student: A User object for the student to grade
|
|
course: A Descriptor containing the course to grade
|
|
student_module_cache: A StudentModuleCache initialized with all
|
|
instance_modules for the student
|
|
|
|
If the student does not have access to load the course module, this function
|
|
will return None.
|
|
|
|
"""
|
|
|
|
|
|
# TODO: We need the request to pass into here. If we could forgo that, our arguments
|
|
# would be simpler
|
|
course_module = get_module(student, request,
|
|
course.location, student_module_cache,
|
|
course.id)
|
|
if not course_module:
|
|
# This student must not have access to the course.
|
|
return None
|
|
|
|
chapters = []
|
|
# Don't include chapters that aren't displayable (e.g. due to error)
|
|
for chapter_module in course_module.get_display_items():
|
|
# Skip if the chapter is hidden
|
|
hidden = chapter_module.metadata.get('hide_from_toc','false')
|
|
if hidden.lower() == 'true':
|
|
continue
|
|
|
|
sections = []
|
|
for section_module in chapter_module.get_display_items():
|
|
# Skip if the section is hidden
|
|
hidden = section_module.metadata.get('hide_from_toc','false')
|
|
if hidden.lower() == 'true':
|
|
continue
|
|
|
|
# Same for sections
|
|
graded = section_module.metadata.get('graded', False)
|
|
scores = []
|
|
|
|
module_creator = lambda descriptor : section_module.system.get_module(descriptor.location)
|
|
|
|
for module_descriptor in yield_dynamic_descriptor_descendents(section_module.descriptor, module_creator):
|
|
|
|
course_id = course.id
|
|
(correct, total) = get_score(course_id, student, module_descriptor, module_creator, student_module_cache)
|
|
if correct is None and total is None:
|
|
continue
|
|
|
|
scores.append(Score(correct, total, graded,
|
|
module_descriptor.metadata.get('display_name')))
|
|
|
|
scores.reverse()
|
|
section_total, graded_total = graders.aggregate_scores(
|
|
scores, section_module.metadata.get('display_name'))
|
|
|
|
format = section_module.metadata.get('format', "")
|
|
sections.append({
|
|
'display_name': section_module.display_name,
|
|
'url_name': section_module.url_name,
|
|
'scores': scores,
|
|
'section_total': section_total,
|
|
'format': format,
|
|
'due': section_module.metadata.get("due", ""),
|
|
'graded': graded,
|
|
})
|
|
|
|
chapters.append({'course': course.display_name,
|
|
'display_name': chapter_module.display_name,
|
|
'url_name': chapter_module.url_name,
|
|
'sections': sections})
|
|
|
|
return chapters
|
|
|
|
|
|
def get_score(course_id, user, problem_descriptor, module_creator, student_module_cache):
|
|
"""
|
|
Return the score for a user on a problem, as a tuple (correct, total).
|
|
e.g. (5,7) if you got 5 out of 7 points.
|
|
|
|
If this problem doesn't have a score, or we couldn't load it, returns (None,
|
|
None).
|
|
|
|
user: a Student object
|
|
problem_descriptor: an XModuleDescriptor
|
|
module_creator: a function that takes a descriptor, and returns the corresponding XModule for this user.
|
|
Can return None if user doesn't have access, or if something else went wrong.
|
|
cache: A StudentModuleCache
|
|
"""
|
|
if not (problem_descriptor.stores_state and problem_descriptor.has_score):
|
|
# These are not problems, and do not have a score
|
|
return (None, None)
|
|
|
|
correct = 0.0
|
|
|
|
instance_module = student_module_cache.lookup(
|
|
course_id, problem_descriptor.category, problem_descriptor.location.url())
|
|
|
|
if not instance_module:
|
|
# If the problem was not in the cache, we need to instantiate the problem.
|
|
# Otherwise, the max score (cached in instance_module) won't be available
|
|
problem = module_creator(problem_descriptor)
|
|
if problem is None:
|
|
return (None, None)
|
|
instance_module = get_instance_module(course_id, user, problem, student_module_cache)
|
|
|
|
# If this problem is ungraded/ungradable, bail
|
|
if not instance_module or instance_module.max_grade is None:
|
|
return (None, None)
|
|
|
|
correct = instance_module.grade if instance_module.grade is not None else 0
|
|
total = instance_module.max_grade
|
|
|
|
if correct is not None and total is not None:
|
|
#Now we re-weight the problem, if specified
|
|
weight = getattr(problem_descriptor, 'weight', None)
|
|
if weight is not None:
|
|
if total == 0:
|
|
log.exception("Cannot reweight a problem with zero total points. Problem: " + str(instance_module))
|
|
return (correct, total)
|
|
correct = correct * weight / total
|
|
total = weight
|
|
|
|
return (correct, total)
|