Calculate observed variant prevalence at time t given logistic growth

This function calculates the observed variant prevalence after t time steps (e.g., days) given a logistic growth rate and initial variant prevalence.

varfreq_freq_logistic(t, p0_v1, r_v1, c_ratio = 1)

Arguments

t

time step number (e.g., days) at which to calculate prevalence

p0_v1

initial variant prevalence (# introductions / infected population size)

r_v1

logistic growth rate

c_ratio

coefficient of detection ratio, calculated as the ratio of the coefficients of variant 1 to variant 2; default = 1 (no bias)

Value

scalar giving the variant prevalence at time t

See also

Other logistic growth functions: varfreq_cdf_logistic()

Other variant frequency functions: varfreq_cdf_logistic(), varfreq_expected_mbias(), varfreq_obs_freq()

Author

Shirlee Wohl, Elizabeth C. Lee, Bethany L. DiPrete, and Justin Lessler

Examples

varfreq_freq_logistic(t = 30, p0_v1 = 1/10000, r_v1 = 0.1, c_ratio = 1)
#> [1] 0.002004728