how: implement the model

[lhaze]

• [ ] population of alive people

• [x] natural growth (mind that it is the natural growth on the other side of the Shroud)

• [ ] population of wraiths per DoD

• [ ] population of wraiths en masse

• [ ] population of shades

• [x] migration of wraiths

• [ ] alive population pyramid per year

• [ ] population pyramid per year

[lhaze]

natural growth

natural_growth(t) = lambda t: int(deaths(t) * wraith_turn_factor(t)) + migration(t)

deaths(t) = lambda t: int(alive_population(t) * mortality_rate(t)) + additional_deaths(t)

migration(t) = lambda t: int((immigration_rate(t) + emigration_rate(t)) * population(t-1))

immigration

is proportional to population of wraiths. One can consider it mostly dependent on wraiths from towns, villages and suburbs of the very City moving into the Citadel for safety or because their Fetters are moving into the City. There is some sense to assume that the amount of immigration to be proportional to the population of the region which roughly is proportional to the population of the City itself. Immigration rate can be considered rising up from the beginning of the industrial age as a process of the urbanization is approaching its climax.

emigration

can be assumed to be just a fraction of the population of the Citadel moving forward, towards the Stygia or other, bigger Citadels.

[lhaze]

real growth

real_growth(t) = lambda t: int(natural_growth(t) * (1 - enfant_survavibility_rate(t)))

shades_growth(t) = lambda t: int(natural_growth(t) * enfant_oblivion_rate(t) + \
    population(t - 1) * senior_oblivion_rate(t))