polyparse {ivmte}

Parsing marginal treatment response formulas

Description

This function takes in an MTR formula, and then parses the formula such that it becomes a polynomial in the unobservable u. It then breaks these polynomials into monomials, and then integrates each of them with respect to u. Each integral corresponds to E[md | D, X, Z].

Usage

polyparse(
  formula,
  data,
  uname = "u",
  env = parent.frame(),
  as.function = FALSE
)

Arguments

formula

the MTR.

data

data.frame for which we obtain E[md | D, X, Z] for each observation.

uname

variable name for unobservable used in declaring the MTR.

env

environment, the original environment in which the formula was declared.

as.function

boolean, if FALSE then a list of the polynomial terms are returned; if TRUE then a list of functions corresponding to the polynomials are returned.

Value

A list (of lists) of monomials corresponding to the original MTR (for each observation); a list (of lists) of the integrated monomials; a vector for the degree of each of the original monomials in the MTR; and a vector for the names of each variable entering into the MTR (note x^2 + x has only one term, x).

Examples

dtm <- ivmte:::gendistMosquito()

## Declare MTR functions
formula1 = ~ 1 + u
formula0 = ~ 1 + u

## Construct MTR polynomials
polynomials0 <- polyparse(formula = formula0,
                          data = dtm,
                          uname = u,
                          as.function = FALSE)

polynomials1 <- polyparse(formula = formula0,
                          data = dtm,
                          uname = u,
                          as.function = FALSE)