lib/converter/roi.ex
defmodule Exoddic.Converter.Roi do
@behaviour Exoddic.Converter
@moduledoc """
Per-unit return on investment
"""
def from_prob(amount) when amount == 0, do: 0.0
def from_prob(amount) when amount != 0, do: 1 / amount - 1
def to_prob(amount) when amount == 0, do: 0.0
def to_prob(amount) when amount != 0, do: 1 / (amount + 1)
@doc "Formatted as an integer percentage"
def for_display(amount), do: "#{round(amount * 100)}%"
end