R/utils.R

In targeted: Targeted Inference

Identical <- function(x, y=1, tolerance=.Machine$double.eps^0.5) {
    Mod(x-y) < tolerance
}

rd2pr <- function(rd, op) {
    a <- op - 1
    b <- -op*(2-rd) - rd
    p0 <- (-b  - sqrt(b^2 - 4*op*(1-rd)*a))/(2*a)
    op1 <- which(sapply(op, function(x) Identical(x, 1)))
    if (length(op1) > 0)
        p0[op1] = 0.5 * (1 - rd[op1])
    p1 <- p0 + rd
    cbind(p0, p1)
}

rr2pr <- function(rr, op) {
    b <- op*(1 + rr)
    a <- rr*(1 - op)
    p0 <- (-b + sqrt(b^2 + 4*a*op))/(2*a)
    op1 <- which(sapply(op, function(x) Identical(x, 1)))
    if (length(op1) > 0)
        p0[op1] = 1/(1+rr[op1])
    p1 <- p0*rr
    cbind(p0, p1)
}