time_units: generations
defaults:
  epoch: {size_function: constant}
demes:
- name: a
  epochs:
  - {start_size: 1}
- name: b
  epochs:
  - {start_size: 1}
- name: c
  epochs:
  - {start_size: 1}
- name: d
  ancestors: [a, b, c]
  proportions: [0.2, 0.3, 0.5]
  start_time: 100
  epochs:
  - {start_size: 1, end_time: 50}
  - {start_size: 1, end_size: 100, size_function: exponential}
- name: e
  ancestors: [a, b, c]
  proportions: [0.2, 0.3, 0.5]
  start_time: 100
  epochs:
  - {start_size: 1, end_time: 90, size_function: constant}
  - {start_size: 1, end_size: 100, end_time: 50}
  - {start_size: 100, end_size: 50, end_time: 10}
  - {start_size: 100, end_size: 100}
  defaults:
    epoch: {size_function: exponential}