Module:Rational: Difference between revisions
Re-comment some functions; implement log base 2 from module: Utils |
Sorting functions |
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| Line 923: | Line 923: | ||
end | end | ||
return logarithm | return logarithm | ||
end | |||
-- convert a rational number to its size in cents | |||
function p.cents(a) | |||
if type(a) == 'number' then | |||
a = p.new(a) | |||
end | |||
if a.nan or a.inf or a.zero or a.sign < 0 then | |||
return nil | |||
end | |||
local c = 0 | |||
for factor, power in pairs(a) do | |||
if type(factor) == 'number' then | |||
c = c + power * u._log(factor, base) | |||
end | |||
end | |||
return c * 1200 | |||
end | |||
-- convert a rational number (interpreted as an interval) into Hz | |||
function p.hz(a, base) | |||
base = base or 440 | |||
if type(a) == 'number' then | |||
a = p.new(a) | |||
end | |||
if a.nan or a.inf or a.sign < 0 then | |||
return nil | |||
end | |||
if a.zero then | |||
return 0 | |||
end | |||
local log_hz = math.log(base) | |||
for factor, power in pairs(a) do | |||
if type(factor) == 'number' then | |||
log_hz = log_hz + power * math.log(factor) | |||
end | |||
end | |||
return math.exp(log_hz) | |||
end | end | ||
| Line 1,172: | Line 1,210: | ||
end | end | ||
return n_factors <= 1 and m_factors <= 1 | return n_factors <= 1 and m_factors <= 1 | ||
end | end | ||