def execute(prefs, print_output=True, recursion_limit=10000):
# adjust the system's recursion call depth limit
# system default is 1000
sys.setrecursionlimit(recursion_limit)
# SETUP --> CREATE PERSON OBJECTS
Person.setup(prefs)
if print_output:
print("Starting Preference Matrix -- Phase 0 Complete:")
pprint.pprint(Person.prefsMatrix('current'))
# PHASE 1
#core of phase 1 --> everybody proposes to their top choice
for person in Person.ppl.values():
# before proposing, we need to make sure everybody hasn't rejected them yet!
# this would happen iff everybody else has already received better offers...
if len(person.current_prefs) > 0:
person.propose_to(person.current_prefs[0]) # propose to your top choice
if print_output:
print("Phase 1 Complete:")
pprint.pprint(Person.prefsMatrix('current'))
# does anybody have an empty column at the end of phase one?
has_empty_column_after_phase_one = Person.empty_column()
print("Empty column --> " + str(has_empty_column_after_phase_one))
# PHASE 2
#find the initial person with a second column
current_person = Person.find_person_with_second_column()
num_rotations = 1 # number of rotations so far...
# while we still have a person with a second column
while current_person:
# grab their second choice preference
current_pref = current_person.current_prefs[1]
# and cross off that person's last preference....
# which kicks off the rotation
current_pref.cross_off(current_pref.current_prefs[-1])
if print_output:
print("Rotating around person " + current_person.name +
", with preference " + current_pref.name)
print("Rotation #" + str(num_rotations) + ":")
num_rotations = num_rotations + 1
pprint.pprint(Person.prefsMatrix('current'))
# find another person to work with... if there is one
current_person = Person.find_person_with_second_column()
if print_output:
print("Phase 2 Complete:")
pprint.pprint(Person.prefsMatrix('current'))
print("\nRESULTS:\n")
# who wasn't matched?
ppl_without_match = Person.who_wasnt_matched()
stable = False
#if everybody was matched, was the match stable?
if len(ppl_without_match) == 0:
stable = Person.was_the_match_stable()
# grab the corresponding result object
result = Result(Person.ppl,ppl_without_match,stable,Person.prefsMatrix("initial"))
if print_output:
result.print_nicely()
# HYPOTHESIS: if there is not an empty column at the end of phase one,
# there should be a stable match --> but this is currently NOT the case
# if (not stable) and (not has_empty_column_after_phase_one):
# raise Exception("The match was unstable, yet there was not an empty column at the end of phase one.")
return result
