trader tool: use result - klog10(price) estimation for value sorting

Author: vaisest

src/Classes/TradeQuery.lua

@@ -358,7 +358,7 @@ on trade site to work on other leagues and realms)]]
 [[Weighted Sum searches will always sort using descending weighted sum
 Additional post filtering options can be done these include:
 Highest Stat Value - Sort from highest to lowest Stat Value change of equipping item
-Highest Stat Value / Price - Sorts from highest to lowest Stat Value per currency
+Highest Stat Value / Price - Sorts from highest to lowest by estimated Stat Value per currency
 Lowest Price - Sorts from lowest to highest price of retrieved items
 Highest Weight - Displays the order retrieved from trade]]
 	-- avoid calling selfunc to avoid updating controls before they are
@@ -858,6 +858,7 @@ function TradeQueryClass:SortFetchResults(row_idx, mode)
 		return newTbl
 	elseif mode == self.sortModes.StatValue  then
 		for result_index = 1, #self.resultTbl[row_idx] do
+			ConPrintf("%.3f", getResultWeight(result_index))
 			t_insert(newTbl, { outputAttr = getResultWeight(result_index), index = result_index })
 		end
 		table.sort(newTbl, function(a,b) return a.outputAttr > b.outputAttr end)
@@ -867,7 +868,20 @@ function TradeQueryClass:SortFetchResults(row_idx, mode)
 			return nil, "MissingConversionRates"
 		end
 		for result_index = 1, #self.resultTbl[row_idx] do
-			t_insert(newTbl, { outputAttr = getResultWeight(result_index) / priceTable[result_index], index = result_index })
+			-- generally, because we are filtering our results to only the top
+			-- contenders, we will end up with a small spread of result weights.
+			-- this is however not true for prices as *decent* items might start
+			-- at a couple of div while perfect items are worth hundreds of
+			-- divs. I think the best option here is weight - k * log10(price)
+			-- to prioritise good items while only slightly punishing high
+			-- prices. another option would be weight / log10(price), but it
+			-- still seems to overrate very cheap items that are bad
+
+			-- scaling factor for price
+			local k = 0.03
+			t_insert(newTbl,
+				{ outputAttr = getResultWeight(result_index) - k * math.log(priceTable[result_index], 10), index =
+				result_index })
 		end
 		table.sort(newTbl, function(a,b) return a.outputAttr > b.outputAttr end)
 	elseif mode == self.sortModes.Price then