The Y deme had a size of 6840 until 8500.31 generations ago. From 8500.31 generations to time 4396.879, its size grew linearly to 8026 individuals. After that, until 1951.0, the population had a linear change to 6747 individuals. It then changed from 6747 to 4490, starting 1951.0 generations ago, until current times, at a exponential rate.
time_units: generations
demes:
  - name: Y
    start_time: .inf
    epochs:
      - start_size: 6840
        end_time: 8500.31
      - start_size: 6840
        end_size: 8026
        end_time: 4396.879
        size_function: linear
      - start_size: 8026
        end_time: 1951.0
        end_size: 6747
        size_function: linear
      - end_time: 0
        start_size: 6747
        end_size: 4490
        size_function: exponential