Provided a vector of per-capita growth rates, this function returns the vector of equivalent doubling times
doubling_time(y, x_scale = 1)
A vector of values for the doubling time equivalent to the
per-capita growth rate supplied for y
Vector of per-capita derivative data to calculate the equivalent doubling time of
Numeric to scale per-capita derivative values by
Set x_scale to the ratio of the the units of
y to the desired units. E.g. if y is in per-second, but the
desired doubling time is in minutes, x_scale = 60
(since there are 60 seconds in 1 minute).