sps_iterator: Iteratively draw a sequential Poisson sample

In sps: Sequential Poisson Sampling

Iteratively draw a sequential Poisson sample

Description

Create a function that draws new units, one at a time, according to the sequential Poisson method without replacing previously sampled units.

Usage

sps_iterator(x, n = 0L, prn = NULL, alpha = 0.001, cutoff = Inf)

Arguments

x	⁠[numeric >= 0]⁠ A positive and finite numeric vector of sizes for units in the population (e.g., revenue for drawing a sample of businesses).
n	⁠[integer(1) >= 0]⁠ A positive integer giving the initial sample size for the iterator. The default is 0.
prn	⁠[0 < numeric < 1]⁠ A numeric vector of permanent random numbers for units in the population, distributed uniform between 0 and 1. The default does not use permanent random numbers, instead generating a random vector when the function is called.
alpha	⁠[0 <= numeric(1) <= 1]⁠ A number between 0 and 1. Units with inclusion probabilities greater than or equal to 1 - alpha are set to 1. The default is slightly larger than 0.
cutoff	⁠[numeric(1) > 0]⁠ A numeric cutoff. Units with x >= cutoff get an inclusion probability of 1. The default does not apply a cutoff.

Value

A function that returns the next unit in the sample. It takes a single argument giving the sentinel value to indicate that there are no units left to sample (default NULL).

See Also

sps() for drawing a sequential Poisson sample.

Examples

prn <- runif(5)
s <- sps_iterator(1:5, prn = prn)
s()
s()
s()

# Same as drawing the sample with 3 units.
sps(1:5, 3, prn = prn)

sps documentation built on Aug. 31, 2026, 5:10 p.m.