37 lines
1.1 KiB
R
37 lines
1.1 KiB
R
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#' Combine Dice
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#'
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#' This function is a way to combine two independent dice rolls into a new die.
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#'
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#' @param x A die
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#' @param y A die
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#' @param fun A function that takes two vectors containing the possible
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#' combinations of die rolls of \code{x} and \code{y}; the output should be of
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#' the same length. Example - \code{pmax} is such a function and is used to
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#' take the maximum of two rolls.
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#'
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#' @return A new die with the possible possibilities and their corresponding
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#' probabilties
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#' @export
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#'
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#' @examples
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#' summed.die <- combineDice(d4, d6, `+`)
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#' advantaged.die <- combineDice(d4, d4, pmax)
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combineDice <- function(x, y, fun){
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rolls <- expand.grid(x.numbers = x$numbers, y.numbers = y$numbers)
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rolls$x.probs <- getProbabilitiy(x, rolls$x.numbers)
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rolls$y.probs <- getProbabilitiy(y, rolls$y.numbers)
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rolls$combined.prob <- rolls$x.probs*rolls$y.probs
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rolls$combined.num <- fun(rolls$x.numbers, rolls$y.numbers)
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new.die.probs <- rolls %>%
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group_by(combined.num) %>%
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summarize(prob = sum(combined.prob)) %>%
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arrange(combined.num)
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new.die <- makeDie(new.die.probs$combined.num, new.die.probs$prob)
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return(new.die)
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}
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