def test_major_progenitor_from_minor_progenitor():
generator = tangos.testing.simulation_generator.TestSimulationGenerator(
"sim3")
ts1 = generator.add_timestep()
generator.add_objects_to_timestep(4)
ts2 = generator.add_timestep()
generator.add_objects_to_timestep(3)
generator.link_last_halos_using_mapping({
1: 2,
2: 1,
3: 3,
4: 1
},
adjust_masses=True)
# ts1->ts2: most massive and second most massive halos swap rank ordering by mass because of the
# merger with ts1/h4.
ts3 = generator.add_timestep()
generator.add_objects_to_timestep(2)
# ts2->ts3: there is a major merger of the most massive halos (ts2/h1+ts2/h2)->ts3/h1
generator.link_last_halos_using_mapping({
1: 1,
2: 1,
3: 2
},
adjust_masses=True)
# Check major progenitor correctly reported one step back by MultiSourceMultiHopStrategy
progen_in_ts2 = halo_finding.MultiSourceMultiHopStrategy(
tangos.get_items(["sim3/ts3/1"]), tangos.get_item("sim3/ts2")).all()
testing.assert_halolists_equal(progen_in_ts2, ['sim3/ts2/1'])
# Check major progenitor correctly reported two steps back by MultiHopMajorProgenitorsStrategy
all_progenitors, weights = halo_finding.MultiHopMajorProgenitorsStrategy(
tangos.get_item("sim3/ts3/1")).all_and_weights()
testing.assert_halolists_equal(all_progenitors,
['sim3/ts2/1', 'sim3/ts1/2'])
# Check major progenitor correctly reported two steps back by MultiSourceMultiHopStrategy
# This is where a failure occurred in the past -- the behaviour was inequivalent to always choosing
# the highest weight branch (which is what MultiHopMajorProgenitorsStrategy does).
#
# In the example constructed above, the mapping from ts3 halo 1 reaches:
# ts1, h4 (weight 0.26)
# ts1, h2 (weight 0.35)
# ts1, h1 (weight 0.39)
#
# It looks from these weights like we ought to be picking ts1/h1.
#
# However the correct major progenitor is h2, because one identifies a major progenitor at each step.
# In step ts2, h1 has weight 0.61 and h2 has weight 0.39. So ts2/h1 is the major progenitor. And then,
# going back to ts3, ts1/h2 (weight 0.57) is the major progenitor to ts2/h1.
progen_in_ts1 = halo_finding.MultiSourceMultiHopStrategy(
tangos.get_items(["sim3/ts3/1"]), tangos.get_item("sim3/ts1")).all()
testing.assert_halolists_equal(progen_in_ts1, ['sim3/ts1/2'])
def test_major_progenitors():
results = halo_finding.MultiHopMajorProgenitorsStrategy(
tangos.get_item("sim/ts3/1"), include_startpoint=True).all()
testing.assert_halolists_equal(results,
["sim/ts3/1", "sim/ts2/1", "sim/ts1/2"])