Module:Rational: Difference between revisions

← Older edit Newer edit →

@@ Line 746: / Line 746: @@
 end
+-- FJS representation of a rational number
+-- might be a bit incorrect
 function p.as_FJS(a)
 	if type(a) == 'number' then
@@ Line 774: / Line 776: @@
 	table.sort(utonal)
 	local fifths = b[3] or 0
-	mw.log(p.as_ratio(b))
-	mw.log('fifths=' .. fifths)
+	if fifths % 7 == 6 then
+		b = p.div(b, red(p.new(2, 3)))
+	else
+		b = p.div(b, red(p.pow(p.new(3, 2), fifths % 7)))
+	end
-	local red3 = red(p.pow(3, fifths))
+	b = p.div(b, p.pow(p.new(2187, 2048), math.floor((fifths + 1) / 7)))
-	mw.log('dividing by ' .. p.as_ratio(red3))
-	b = p.div(b, red3)
 	local octaves = b[2] or 0
-	mw.log('octaves=' .. octaves)
-	if math.abs(fifths) >= 12 and math.abs(fifths) % 7 == 5 then
-		-- still wrong results with 4096/2187: d1 instead of d8
-		octaves = octaves - u.signum(fifths)
-		mw.log('octaves=' .. octaves)
-	end
-	-- a terrible hack, I have no idea how/why this is supposed to work
-	-- local octaves = (b[2] or 0) + fifths + 4 * math.floor(fifths / 7) + math.floor((fifths % 7) / 2)
 	local noshift = {1, 5, 2, 6, 3, 7, 4}
-	local num = noshift[1 + (fifths % 7)] + octaves * 7
+	local base_num = noshift[1 + (fifths % 7)]
+	local num = base_num + octaves * 7
 	if octaves < 0 then
-		mw.log('octaves < 0, inverting')
 		fifths = -fifths
-		-- wrong results on 3^53/2^84, which should be AAAAAAA3 but is computed as ddddddd-6
+		octaves = -octaves - 1
-		-- octaves = -(b[2] or 0) + fifths + 4 * math.floor(fifths / 7) + math.floor((fifths % 7) / 2)
+		base_num = (8 - base_num) % 7 + 1
-		-- num = -noshift[1 + (fifths % 7)] - octaves * 7
+		num = -base_num - octaves * 7
-		if fifths ~= 0 then
-			num = num - 2
-		else
-			num = num + 5
-		end
 	end