Module:Harmonic entropy

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This module primarily serves as a library for other modules and has no corresponding template.

This module provides a means to calculate harmonic Shannon entropy of a particular interval.

Introspection summary for Module:Harmonic entropy
Functions provided (2) Line Function Params Description 6 to_cents (invokable) (frame) 11 _to_cents (ratio, prec)	Lua modules required (2) Variable Module Functions used getArgs Module:Arguments getArgs u Module:Utils eval_num_arg _round _log

---

local getArgs = require('Module:Arguments').getArgs
local u = require('Module:Utils')
local p = {}

-- return measure in cents of an interval ratio, rounded to prec decimal places
function p.to_cents(frame)
	local args = getArgs(frame)
	return p._to_cents(args[1], args[2])
end	

function p._to_cents(ratio, prec)
	-- ratio defaults to 1
	ratio = u.eval_num_arg(ratio, 1)
	-- output without rounding if prec is omitted
	if prec then
		return u._round(1200*u._log(ratio), prec)
	-- output with rounding if prec is given
	else
		-- prec defaults to 3
		prec = u.eval_num_arg(prec, 3)
		return 1200*u._log(ratio)
	end
end

return p