Module:Mediants: Difference between revisions

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@@ Line 5: / Line 5: @@
 -- Module for finding mediants, either by search depth or by search function.
+--------------------------------------------------------------------------------
+------------------------------- FILTER FUNCTIONS -------------------------------
+--------------------------------------------------------------------------------
+-- Filter functions determine whether a mediant meets a specific criteria (eg,
+-- int limit), based on either the mediant itself, its search depth, or both.
+-- This filter adds (or excludes) mediants based on int limit, and does nothing
+-- with the depth param.
+function p.int_limit_filter(mediant, depth, int_limit)
+	local int_max = math.max(mediant[1], mediant[2])
+	return int_max <= int_limit
+end
+-- This filter adds (or excludes) mediants based on search depth, and does
+-- nothing with the mediant itself.
+function p.search_depth_filter(mediant, depth, search_depth)
+	return depth <= search_depth
+end
+--------------------------------------------------------------------------------
+------------------------------- SEARCH FUNCTIONS -------------------------------
+--------------------------------------------------------------------------------
+-- Find mediants by depth, how many times mediants are found in a set of ratios.
 function p.find_mediants_by_depth(init_ratios, depth)
 	local init_ratios = init_ratios or {{1,1}, {1,0}}
 	local depth = depth or 5
 	local ratios = {}
 	local depths = {}
-	for i = 1, #init_ratios do
+	local filter_arg = depth
-		table.insert(ratios, init_ratios[i])
+	local filter_func = p.search_depth_filter
-		table.insert(depths, 0)
-	end
-	for i = 1, depth do
+	ratios, depths = p.find_mediants_by_filter(init_ratios, filter_func, filter_arg)
-		local new_ratios = {}
-		local new_depths = {}
-		for j = 1, #ratios - 1 do
-			local ratio_1 = ratios[j]
-			local ratio_2 = ratios[j+1]
-			local mediant = { ratio_1[1] + ratio_2[1], ratio_1[2] + ratio_2[2] }
-			table.insert(new_ratios, ratio_1)
-			table.insert(new_ratios, mediant)
-			local depth_1 = depths[j]
-			local depth_2 = depths[j+1]
-			table.insert(new_depths, depth_1)
-			table.insert(new_depths, math.max(depth_1, depth_2) + 1)
-		end
-		table.insert(new_ratios, ratios[#ratios])
-		table.insert(new_depths, depths[#depths])
-		ratios = new_ratios
-		depths = new_depths
-	end
 	return ratios, depths
 end
--- Filter functions calculate whether a mediant is allowed to be added to the
+-- Find mediants by filter, where the filter function and its args are passed in
--- running set of mediants, and are passed to the find-mediants-by-filter
+-- as part of the function call.
--- function as a parameter, followed by its arg(s).
-function p.int_limit_filter(ratio_1, ratio_2, int_limit)
-	local mediant = { ratio_1[1] + ratio_2[1], ratio_1[2] + ratio_2[2] }
-	local int_max = math.max(mediant[1], mediant[2])
-	return int_max <= int_limit
-end
 function p.find_mediants_by_filter(init_ratios, filter, filter_arg)
 	local init_ratios = init_ratios or {{1,1}, {1,0}}
@@ Line 70: / Line 64: @@
 			local ratio_1 = ratios[i]
 			local ratio_2 = ratios[i+1]
+			local mediant = { ratio_1[1] + ratio_2[1], ratio_1[2] + ratio_2[2] }
 			table.insert(new_ratios, ratio_1)
-			if filter(ratio_1, ratio_2, filter_arg) then
+			local depth_1 = depths[i]
-				local mediant = { ratio_1[1] + ratio_2[1], ratio_1[2] + ratio_2[2] }
+			local depth_2 = depths[i+1]
+			local new_depth = math.max(depth_1, depth_2) + 1
+			table.insert(new_depths, depth_1)
+			if filter(mediant, new_depth, filter_arg) then
 				table.insert(new_ratios, mediant)
+				table.insert(new_depths, new_depth)
 				new_ratios_added = true
 			end
@@ Line 86: / Line 86: @@
 	return ratios, depths
 end
+--------------------------------------------------------------------------------
+----------------------------------- TESTER -------------------------------------
+--------------------------------------------------------------------------------
 function p.tester()