foxes

This file calculates the birth rate, death rate, and population of foxes.

fox_births

fox_births[ t ] is the number of foxes born during time t.

table fox_births : time -> general.

fox_births[ t ] =
  number_of_foxes[ t ] *
  birth_rate_of_foxes[] *
  ( number_of_rabbits[ t ] / 10 ) *
  0.001.

fox_deaths

fox_deaths[ t ] is the number of foxes killed during time t.

table fox_deaths : time -> general.

fox_deaths[ t ] =
  number_of_foxes[ t ] *
  death_rate_of_foxes[] *
  0.05.

number_of_foxes

number_of_foxes[ t ] is the population of foxes at time t.

table number_of_foxes : time -> general.

number_of_foxes[ 1 ] =
  initial_number_of_foxes[].

number_of_foxes[ t>1 ] =
  number_of_foxes[ t-1 ] +
  fox_births[ t-1 ] -
  fox_deaths[ t-1 ].

initial_number_of_foxes

initial_number_of_foxes[] is the fox population at time 1. This is input by the user.

table initial_number_of_foxes : -> general.

initial_number_of_foxes[] =
  30.

birth_rate_of_foxes

birth_rate_of_foxes[] is the proportion of foxes born in a year. It is input by the user.

table birth_rate_of_foxes : -> general.

birth_rate_of_foxes[] =
  1.

death_rate_of_foxes

death_rate_of_foxes[] is the proportion of foxes that die in a year. It is input by the user.

table death_rate_of_foxes : -> general.

death_rate_of_foxes[] =
  1.