downsample maxmins done

src/HushGP/GP.hs

@@ -15,8 +15,8 @@ import HushGP.Genome
 -- | Using a PushArgs object, generates a population of the specified size with the
 -- specified instructions in parallel.
 generatePopulation :: PushArgs -> IO [Individual]
-generatePopulation pushArgs = do
-  pop <- replicateM (populationSize pushArgs) (makeRandomIndividual pushArgs)
+generatePopulation pushArgs@(PushArgs {populationSize = popSize}) = do
+  pop <- replicateM popSize (makeRandomIndividual pushArgs)
   return (pop `using` evalList rpar) -- Does this work? Need to test this with the HEC viewing tool.
 
 -- | Evaluates a population of plushies with the error function passed in via PushArgs and sorts them.
@@ -32,9 +32,9 @@ updateIndividual errors ind = ind {totalFitness = Just (sum errors), fitnessCase
 -- | The start of the gp loop. Generates the population and then calls
 -- gpLoop' with modifications to the variables if needed.
 gpLoop :: PushArgs -> IO ()
-gpLoop pushArgs = do
+gpLoop pushArgs@(PushArgs {trainingData = tData}) = do
   unEvaledPopulation <- generatePopulation pushArgs
-  let indexedTrainingData = assignIndiciesToData (trainingData pushArgs)
+  let indexedTrainingData = assignIndiciesToData tData
   gpLoop' pushArgs 0 0 unEvaledPopulation indexedTrainingData
 
 -- | The guts of the GP loop. Where the work gets done after the initialization happens

src/HushGP/GP/Downsample.hs

@@ -2,10 +2,12 @@ module HushGP.GP.Downsample where
 
 import System.Random.Shuffle
 import System.Random
+import Data.List
 import HushGP.Genome
 import HushGP.GP.PushData
 import HushGP.GP.PushArgs
-import Data.List
+import HushGP.Tools.Metrics
+import HushGP.Instructions.Utility
 
 -- |Sets the index of the passed training data.
 assignIndiciesToData :: [PushData] -> [PushData]
@@ -21,7 +23,7 @@ updateCaseDistances evaledPop downsampleData trainingData informedDownsamplingTy
 
 -- |Draws a random amount of data points from a passed list of data points.
 selectDownsampleRandom :: PushArgs -> [PushData] -> IO [PushData]
-selectDownsampleRandom pushArgs pushData = take (floor (downsampleRate pushArgs * fromIntegral @Int @Float (length pushData))) . shuffle' pushData (length pushData) <$> initStdGen
+selectDownsampleRandom (PushArgs {downsampleRate = dsRate}) pushData = take (floor (dsRate * fromIntegral @Int @Float (length pushData))) . shuffle' pushData (length pushData) <$> initStdGen
 
 -- |Selects a downsample that has it's cases maximally far away by sequentially
 -- adding cases to the downsample that have their closest case maximally far away.
@@ -43,5 +45,40 @@ selectDownsampleMaxmin' :: [PushData] -> [PushData] -> Int -> IO [PushData]
 selectDownsampleMaxmin' newDownsample casesToPickFrom goalSize
   | length newDownsample >= goalSize = pure newDownsample
   | otherwise = do
-      minCaseDistances
+      let newDistances = map extractDistance newDownsample
+      let minCaseDistances = minOfColumns (map (\distList -> filterByIndex distList (map extractIndex casesToPickFrom)) newDistances)
+      selectedCaseIndex <- argMax minCaseDistances
+      stdGen <- initStdGen
+      selectDownsampleMaxmin'
+        ((casesToPickFrom !! selectedCaseIndex) : newDownsample)
+        (shuffle' (deleteAt selectedCaseIndex casesToPickFrom) (length casesToPickFrom - 1) stdGen)
+        goalSize
 
+-- |selects a downsample that has it's cases maximally far away by sequentially 
+-- adding cases to the downsample that have their closest case maximally far away
+-- automatically stops when the maximum minimum distance is below delta
+selectDownsampleMaxminAdaptive :: PushArgs -> [PushData] -> IO [PushData]
+selectDownsampleMaxminAdaptive (PushArgs {caseDelta = cDelta}) pushData = do
+  shuffledCases <- shuffle' pushData (length pushData) <$> initStdGen
+  selectDownsampleMaxminAdaptive'
+    (case uncons shuffledCases of (Just (x, _)) -> [x]; _ -> error "error: shuffledCases empty!")
+    (drop 1 shuffledCases)
+    cDelta
+
+-- |The main loop of selectDownsampleMaxmin. This is where most of calculation happens.
+-- When called from selectDownsampleMaxmin: The first [PushData] holds the head of the
+-- original pushData wrapped in a list, the second [PushData] holds the rest of the list
+-- without the aformentioned head. The Int is the caseDelta derived from the downsample rate
+-- and the length of the original [pushData].
+selectDownsampleMaxminAdaptive' :: [PushData] -> [PushData] -> Double -> IO [PushData]
+selectDownsampleMaxminAdaptive' newDownsample casesToPickFrom cDelta = do
+      let newDistances = map extractDistance newDownsample
+      let minCaseDistances = minOfColumns (map (\distList -> filterByIndex distList (map extractIndex casesToPickFrom)) newDistances)
+      selectedCaseIndex <- argMax minCaseDistances
+      stdGen <- initStdGen
+      if null casesToPickFrom || (maximum minCaseDistances <= cDelta)
+      then pure newDownsample
+      else selectDownsampleMaxminAdaptive'
+            ((casesToPickFrom !! selectedCaseIndex) : newDownsample)
+            (shuffle' (deleteAt selectedCaseIndex casesToPickFrom) (length casesToPickFrom - 1) stdGen)
+            cDelta

src/HushGP/GP/PushArgs.hs

@@ -93,7 +93,10 @@ data PushArgs = PushArgs
     -- Takes a Map of String -> Float where the string is the genetic operator
     variation :: Map.Map String Float,
     -- | The epsilons calculated for epsilon lexicase selection. Only used for epsilon lexicase selection.
-    epsilons :: Maybe [Double]
+    epsilons :: Maybe [Double],
+    -- | Used with the CaseMaxminAuto downsampling strategy. Tells downsampling to stop when
+    -- the maximum minimum distance is too far away.
+    caseDelta :: Double
   }
 
 -- | The default values for which all runs of Hush derive
@@ -139,5 +142,6 @@ defaultPushArgs = PushArgs {
     trainingData = error "Must supply the trainingData yourself",
     umadRate = 0.1,
     variation = Map.fromList [("umad", 1.0)],
-    epsilons = Nothing
+    epsilons = Nothing,
+    caseDelta = 0.0
   }

src/HushGP/GP/PushData.hs

@@ -12,4 +12,20 @@ data PushData = PushData {
   _caseDistances :: Maybe [Double]
 } deriving (Show)
 
+-- |Extracts the case distances from a PushData object. Errors if the
+-- _caseDistances list is Nothing.
+extractDistance :: PushData -> [Double]
+extractDistance PushData{_caseDistances = Nothing} = error "Error: Case distances are empty!. This should never happen"
+extractDistance PushData{_caseDistances = Just xs} = xs
+
+-- |Extracts the downsample index from a PushData object. Errors if the
+-- _downsampleIndex is Nothing.
+extractIndex :: PushData -> Int
+extractIndex PushData{_downsampleIndex = Nothing} = error "Error: Case distances are empty!. This should never happen"
+extractIndex PushData{_downsampleIndex = Just x} = x
+
+-- |Filters a list by another list of indicies.
+filterByIndex :: [a] -> [Int] -> [a]
+filterByIndex origList = map (origList !!)
+
 $(makeLenses ''PushData)

src/HushGP/Tools/Metrics.hs

@@ -1,3 +1,20 @@
 module HushGP.Tools.Metrics where
 
+import Data.List
+import System.Random
+import System.Random.Shuffle
 
+-- |Maps minimum over the transposed [[Double]].
+minOfColumns :: [[Double]] -> [Double]
+minOfColumns columns = map minimum (transpose columns)
+
+-- |Returns the index of the maximum value in a list, randomly tiebreaking.
+argMax :: Ord a => [a] -> IO Int
+argMax xs = argMaxHead . shuffle' (elemIndices (maximum xs) xs) (length xs) <$> initStdGen
+
+-- |Takes the first element from a list and returns an error as specified. For use with
+-- the argMax function.
+argMaxHead :: [a] -> a
+argMaxHead xs = case uncons xs of
+  Just (x, _) -> x
+  _ -> error "Error: Head is empty in argMax!"