Module:TAMNAMS: Difference between revisions

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@@ Line 79: / Line 79: @@
 }
--- Lookup table for official tamnams names
+-- Lookup table for tamnams names within the range of 6-10 steps
 p.tamnams_name = {
 	['1L 1s'] = 'monowood',
@@ Line 296: / Line 296: @@
 end
-function p.lookup_named_ancestor(input_mos)
+-- Given a mos, find the ancestor mos within the target note count.
+function p.find_ancestor(input_mos, target_note_count)
+	local target_note_count = target_note_count or 10
+	local z = input_mos.nL
+	local w = input_mos.ns
+	while (z ~= w) and (z + w > target_note_count) do
+		local m1 = math.max(z, w)
+		local m2 = math.min(z, w)
+		-- For use with updating ancestor mos chunks
+		local z_prev = z
+		-- Update step ratios
+		z = m2
+		w = m1 - m2
+	end
+	return p.new(z, w, mos.equave)
+end
+-- Given a mos, find the ancestor mos within the target note count, while also
+-- returning the step ancestor's step ratio range (as two ratios) and the number
+-- of generations between the two mosses. (A more in-depth version of the prev.)
+function p.find_ancestor_info(input_mos, target_step_count)
+	local target_step_count = target_step_count or 10
+	-- For an ancestor mos zU wv and descendant xL ys, how many steps of size
+	-- L and s can fit inside U and v? (basically the chunking operation)
+	local z = input_mos.nL
+	local w = input_mos.ns
+	local lg_chunk = { nL = 1, ns = 0 }
+	local sm_chunk = { nL = 0, ns = 1 }
+	local generations = 0
+	while (z ~= w) and (z + w > target_step_count) do
+		local m1 = math.max(z, w)
+		local m2 = math.min(z, w)
+		-- For use with updating ancestor mos chunks
+		local z_prev = z
+		-- Count how many generations
+		generations = generations + 1
+		-- Update step ratios
+		z = m2
+		w = m1 - m2
+		-- Update large chunk
+		local prev_lg_chunk = { nL = lg_chunk.nL, ns = lg_chunk.ns }
+		lg_chunk.nL = lg_chunk.nL + sm_chunk.nL
+		lg_chunk.ns = lg_chunk.ns + sm_chunk.ns
+		-- Update small chunk
+		if z ~= z_prev then
+			sm_chunk = prev_lg_chunk
+		end
+	end
+	-- Translate chunks into step ratios
+	local ratio_1, ratio_2
+	if num1/den1 < num2/den2 then
+		ratio_1 = { lg_chunk.nL + lg_chunk.ns, sm_chunk.nL + sm_chunk.ns }
+		ratio_2 = { lg_chunk.nL, sm_chunk.nL }
+	else
+		ratio_2 = { lg_chunk.nL + lg_chunk.ns, sm_chunk.nL + sm_chunk.ns }
+		ratio_1 = { lg_chunk.nL, sm_chunk.nL }
+	end
+	return mos.new(z, w), ratio_1, ratio_2, generations
 end