dist_skel: Distribution Skeleton

In epiforecasts/EpiNow: Estimate Realtime Case Counts and Time-varying Epidemiological Parameters

Description

This function acts as a skeleton for a truncated distribution defined by model type, maximum value and model parameters. It is designed to be used with the output from get_dist.

Usage

dist_skel(n, dist = FALSE, cum = TRUE, model, params, max_value = 120)

Arguments

n	Numeric vector, number of samples to take (or days for the probability density).
dist	Logical, defaults to FALSE. Should the probability density be returned rather than a number of samples.
cum	Logical, defaults to TRUE. If dist = TRUE should the returned distribution be cumulative.
model	Character string, defining the model to be used. Supported options are exponential ("exp"), gamma ("gamma"), and log normal ("lognorm")
params	A list of parameters values (by name) required for each model. For the exponential model this is a rate parameter and for the gamma model this is alpha and beta.
max_value	Numeric, the maximum value to allow. Defaults to 120. Samples outside of this range are resampled.

Value

A vector of samples or a probability distribution.

Examples

## Exponential model

## Sample
dist_skel(10, model = "exp", params = list(rate = 1))

## Cumulative prob density
dist_skel(1:10, model = "exp", dist = TRUE, params = list(rate = 1))

## Probability density
dist_skel(1:10, model = "exp", dist = TRUE, 
          cum = FALSE, params = list(rate = 1))

## Gamma model

dist_skel(10, model = "gamma", params = list(alpha = 1, beta = 2))

## Cumulative prob density
dist_skel(0:10, model = "gamma", dist = TRUE,
          params = list(alpha = 1, beta = 2))

## Probability density
dist_skel(0:10, model = "gamma", dist = TRUE, 
          cum = FALSE, params = list(alpha = 2, beta = 2))

## Log normal model

dist_skel(10, model = "lognorm", params = list(mean = log(5), sd = log(2)))

## Cumulative prob density
dist_skel(0:10, model = "lognorm", dist = TRUE,
          params = list(mean = log(5), sd = log(2)))

## Probability density
dist_skel(0:10, model = "lognorm", dist = TRUE, cum = FALSE,
          params = list(mean = log(5), sd = log(2)))
        

epiforecasts/EpiNow documentation built on Oct. 26, 2020, 2:38 p.m.