R: Get Constraints for Product-Multinomial Probabilities

Ab_multinom {multinomineq}

R Documentation

Get Constraints for Product-Multinomial Probabilities

Description

Get or add inequality constraints (or vertices) to ensure that multinomial probabilities are positive and sum to one for all choice options within each item type.

Usage

Ab_multinom(options, A = NULL, b = NULL, nonneg = FALSE)

Arguments

`options`	number of observable categories/probabilities for each item type/multinomial distribution, e.g., `c(3,2)` for a ternary and binary item.
`A`	a matrix defining the convex polytope via `A*x <= b`. The columns of `A` do not include the last choice option per item type and thus the number of columns must be equal to `sum(options-1)` (e.g., the column order of `A` for `k = c(a1,a2,a2, b1,b2)` is `c(a1,a2, b1)`).
`b`	a vector of the same length as the number of rows of `A`.
`nonneg`	whether to add constraints that probabilities must be nonnegative

Details

If A and b are provided, the constraints are added to these inequality constraints.

Examples

# three binary and two ternary choices:
options <- c(2, 2, 2, 3, 3)
Ab_multinom(options)
Ab_multinom(options, nonneg = TRUE)