Find the smallest ship at each period in the Omosso p392_pairs census

filter_p392_pairs.py

# Before using this code the textcensus needs to be fetched from Catagolue.
# $curl -o stdin_c98_pairs.txt https://catagolue.appspot.com/textcensus/b2k3acijr4ijqy6i7cs2aek3ijnqr4it5n/stdin_c98_pairs
# Format: "{apgcode}", {count}

import lifelib
import sys

omosso = "b2k3acijr4ijqy6i7cs2aek3ijnqr4it5n"
lt = lifelib.load_rules(omosso).lifetree(memory=4000)

def get_minima(ship, period):
  minpop = ship.population
  bbox = ship.bounding_box
  minbbox = bbox[2] * bbox[3]
  for _ in range(period):
    ship = ship[1]
    pop = ship.population
    if pop < minpop:
      minpop = pop
      bbox = ship.bounding_box
      minbbox = bbox[2] * bbox[3]
    elif pop == minpop:
      bbox = ship.bounding_box
      bboxarea = bbox[2] * bbox[3]
      minbbox = min(minbbox, bboxarea)
  return minpop, minbbox


def maxminofabs(v):
  v = [abs(x) for x in v]
  return max(v), min(v)


# Process all c/98 ships in Omosso census
shipMinima = {}
minShips = {}
N = 0
with open("stdin_c98_pairs.txt") as Fin:
  for line in Fin.readlines():
    N += 1
    shipstr = line.split(",")[0].strip('"')
    if not shipstr.startswith("xq"):
      continue
    period = int(shipstr.split("_")[0][2:])
    if period in [12, 16, 100, 98, 196, 294, 392, 490, 588, 686, 784, 882, 980]:
      # Ignore periods already known to 5S
      continue
    ship = lt.pattern(shipstr)
    speed = maxminofabs(ship.displacement) + (period,)
    minima = get_minima(ship, period)
    try:
      if minima < shipMinima[speed]:
        shipMinima[speed] = minima
        minShips[speed] = shipstr
    except KeyError:
      shipMinima[speed] = minima
      minShips[speed] = shipstr
    if (N % 100) == 0:
      print('.', end='')
      sys.stdout.flush()
print()


# Write minimum ships to file
with open("omosso_ships.txt", "w") as Fout:
  for speed, shipstr in sorted(minShips.items()):
    minima = shipMinima[speed]
    shiprle = lt.pattern(shipstr).rle_string()
    print(', '.join(map(str, minima[0:1] + speed)))
    print(shiprle, file=Fout)