def check_if_has_holes(sln: RegionMap):
districts = sln.districts
for dist in districts:
neighboring_districts = sln.get_neighboring_districts_of(dist)
if len(neighboring_districts) > 1:
continue
units_on_region_border = dist.get_district_units_on_region_border()
if len(units_on_region_border) == 0:
return True
return False
def create_neighboring_sln(cur_sln: RegionMap):
"""Generates a neighboring solution using the Ising models approach"""
# if unit borders several districts, choose one of these districts randomly
# decide randomly if unit should "go" to another district
all_units = Units.units()
for cur_unit in all_units:
cur_district = cur_sln.find_district_by_unit(cur_unit)
# if cur_unit is the only unit in the district, do not change cur_unit "membership"
# (in favor of another district)
if len(cur_district) <= 1:
continue
neighboring_districts_collection = cur_sln.get_neighboring_districts_of(cur_district)
# find those districts that cur_unit borders
districts_that_cur_unit_borders = []
for neighboring_district in neighboring_districts_collection:
bordering_units = cur_district.get_units_bordering_that_district(neighboring_district)
if cur_unit in bordering_units:
districts_that_cur_unit_borders.append(neighboring_district)
if len(districts_that_cur_unit_borders) == 0:
continue
random_district = rd.choice(districts_that_cur_unit_borders)
cur_district.remove_unit(cur_unit)
random_district.add_unit(cur_unit)
# revert the move if it breaks contiguity or if the move creates holes
if not check_if_contiguous(cur_district) or check_if_has_holes(cur_sln):
random_district.remove_unit(cur_unit)
cur_district.add_unit(cur_unit)
return cur_sln