For the O deme, the population size remained at 8140 until 8046.4 generations ago, at which point a exponential change took place until 7802.7 generations for size 4156. Afterward, the population saw an linear increase to 4754 by 2272.689. From 2272.689 generations ago to today, there's been a exponential growth from 4754 to 6718.
time_units: generations
demes:
  - name: O
    start_time: .inf
    epochs:
      - start_size: 8140
        end_time: 8046.4
      - start_size: 8140
        end_size: 4156
        end_time: 7802.7
        size_function: exponential
      - start_size: 4156
        end_time: 2272.689
        end_size: 4754
        size_function: linear
      - end_time: 0
        start_size: 4754
        end_size: 6718
        size_function: exponential