show error messages on bad input/state

2 files changed, 36 insertions, 22 deletions

diff --git a/src/Mind.hs b/src/Mind.hs
index 359293c..d686e24 100644
--- a/src/Mind.hs
+++ b/src/Mind.hs
@@ -76,12 +76,15 @@ insertEdge ns i e
 
 
 -- network computation
-compute :: Network -> [Float] -> [Float] -> Maybe ([Float], [Float])
-compute net input state = 
-  let 
-    s = newState net input state
-    state' = map (Just) s
-  in Just $ (output net input state state', s)
+compute :: Network -> [Float] -> [Float] -> Either String ([Float], [Float])
+compute net input state 
+ | (length input) /= (numInput net) = Left $ "Bad input length: " ++ (show $ length input)
+ | (length state) /= (length $ internalNeurons net) = Left $ "Bad state length: " ++ (show $ length state)  
+ | otherwise = 
+   let 
+      s = newState net input state
+      state' = map (Just) s
+    in Right $ (output net input state state', s)
 
 
 type InputState = ([Float], [Float])
@@ -89,7 +92,7 @@ type NewState = [Maybe Float]
 
 
 output :: Network -> [Float] -> [Float] -> NewState -> [Float]
-output net input state state'= 
+output net input state state' = 
   let 
     numOutput = length $ outputNeurons net
   in 
@@ -97,16 +100,16 @@ output net input state state'=
 
 newState :: Network -> [Float] -> [Float] -> [Float]
 newState net input state =
-  let numInternal = length $ internalNeurons net
-  in fst $ 
-    foldr 
-    (\x (r, ns) ->
-      let (value, ns') = getValue net (input, state) ns (Internal x)
-      in (value:r, ns')
-    )
-    ([], replicate numInternal Nothing)
-    [0..numInternal-1]
-
+    let numInternal = length $ internalNeurons net
+    in fst $ 
+      foldr 
+      (\x (r, ns) ->
+        let (value, ns') = getValue net (input, state) ns (Internal x)
+        in (value:r, ns')
+      )
+      ([], replicate numInternal Nothing)
+      [0..numInternal-1]
+  
 
 
 updateValue :: NewState -> Int -> Float -> NewState
diff --git a/test/MindTest.hs b/test/MindTest.hs
index d8b63cf..01185f1 100644
--- a/test/MindTest.hs
+++ b/test/MindTest.hs
@@ -3,6 +3,7 @@ module MindTest (suite) where
 import Test.Tasty
 import Test.Tasty.HUnit
 import Mind
+import Data.Either
 
 suite :: TestTree
 suite = testGroup "mind tests" $
@@ -64,7 +65,7 @@ networkTests = testGroup "network tests" $
   , testCase "single input, single output" $
     let 
       net = Network 1 [] [[Edge (Input 0, 2.0)]]
-      Just (output, state) = compute net [negate 0.5] []
+      Right (output, state) = compute net [negate 0.5] []
     in (output, state) @?=
     ( [tanh (2.0 * (negate 0.5))]
     , []
@@ -77,7 +78,7 @@ networkTests = testGroup "network tests" $
         , Edge (Input 2, 1.0)
         , Edge (Input 3, 2.0)
         ]]
-      Just (output, state) = compute net [1, 2, 3, 5] []
+      Right (output, state) = compute net [1, 2, 3, 5] []
     in (output, state) @?=
     ( 
       [tanh 
@@ -99,7 +100,7 @@ networkTests = testGroup "network tests" $
           , Edge (Input 3, 1.0)
           ]
         ]
-      Just (output, state) = compute net [1, 2, 3, 5] []
+      Right (output, state) = compute net [1, 2, 3, 5] []
     in (output, state) @?=
     ( 
       [ tanh (2 - 1)
@@ -123,7 +124,7 @@ networkTests = testGroup "network tests" $
           , Edge (Internal 1, 1.0)
           ]
         ]
-      Just (output, state) = compute net [1, 2, 3, 5] [0, 0]
+      Right (output, state) = compute net [1, 2, 3, 5] [0, 0]
     in (output, state) @?=
     ( 
       [ tanh ( (tanh (5-3)) - (tanh (2-1)) ) ]
@@ -138,9 +139,19 @@ networkTests = testGroup "network tests" $
         [ [ Edge (Internal 0, negate 0.5) ] ]
         -- output neurons
         [ [ Edge (Internal 0, 2) ] ]
-      Just result = compute net [] [1.0]
+      Right result = compute net [] [1.0]
     in result @?=
     ( [ tanh $ 2 * (tanh (negate 0.5)) ]
     , [ tanh (negate 0.5) ]
     )
+  , testCase "computation fails for bad input length" $
+    let 
+      net = Network 2 [[]] [[]]
+      result = compute net (replicate 3 1.0) [1]
+    in (isLeft result) @?= True
+  , testCase "computation fails for bad state length" $
+    let 
+      net = Network 2 [[]] [[]]
+      result = compute net (replicate 2 1.0) [1, 1]
+    in (isLeft result) @?= True
   ]