Problem setup

danielholmes · Feb 17, 2018 · 4b58738 · 4b58738
1 parent ee25de3
commit 4b58738
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Showing 3 changed files with 43 additions and 9 deletions.
diff --git a/src/NeuralNet/Cost.hs b/src/NeuralNet/Cost.hs
@@ -1,11 +1,11 @@
-module NeuralNet.Cost (cost) where
+module NeuralNet.Cost (computeCost) where
 
 import Data.Matrix
 import NeuralNet.Matrix
 
 
-cost :: Matrix Double -> Matrix Double -> Double
-cost al y
+computeCost :: Matrix Double -> Matrix Double -> Double
+computeCost al y
   | nrows al /= 1       = error "al should be a row vector"
   | nrows y /= 1        = error "y should be a row vector"
   | ncols y /= ncols al = error "y and al should be same length"

diff --git a/src/NeuralNet/Problem.hs b/src/NeuralNet/Problem.hs
@@ -1,7 +1,11 @@
 module NeuralNet.Problem (Problem (), createProblem, runProblem) where
 
+import System.Random
 import NeuralNet.Example
 import NeuralNet.Net
+import NeuralNet.Layer
+import NeuralNet.Cost
+import NeuralNet.Train
 
 
 type NumIterations = Int
@@ -15,14 +19,44 @@ type IterationNum = Int
 
 type Cost = Double
 
-type Accuracy = Double
+data RunStep = RunStep IterationNum Cost
 
-data RunStep = RunStep IterationNum Cost Accuracy
+
+problemNNDef :: Problem -> NeuralNetDefinition
+problemNNDef (Problem d _ _ _) = d
+
+problemExampleSet :: Problem -> ExampleSet
+problemExampleSet (Problem _ e _ _) = e
+
+problemLearningRate :: Problem -> LearningRate
+problemLearningRate (Problem _ _ l _) = l
+
+problemNumIterations :: Problem -> NumIterations
+problemNumIterations (Problem _ _ _ i) = i
 
 createProblem :: NeuralNetDefinition -> ExampleSet -> LearningRate -> NumIterations -> Problem
 createProblem def examples learningRate numIterations
   | not (isExampleSetCompatibleWithNNDef examples def) = error "Examples not compatible with nn"
+  | numIterations <= 0                                 = error "Must provide positive numIterations"
+  | learningRate <= 0                                  = error "Must provide positive learningRate"
   | otherwise                                          = Problem def examples learningRate numIterations
 
-runProblem :: Problem -> (Double -> Double) -> (NeuralNet, [RunStep])
-runProblem _ _ = (error "TODO", [RunStep 1 1 1])
+runProblem :: StdGen -> Problem -> (NeuralNet, [RunStep])
+runProblem g p = (resultNN, allSteps)
+  where
+    startNN = initNN g (problemNNDef p)
+    startStep = RunStep 0 1
+    iterations = [1..(problemNumIterations p)]
+    allNNAndSteps = reverse (foldl (\steps@((nn,_):_) i -> runProblemStep p i nn : steps) [(startNN, startStep)] iterations)
+    allSteps = map snd allNNAndSteps
+    resultNN = fst (last allNNAndSteps)
+
+runProblemStep :: Problem -> IterationNum -> NeuralNet -> (NeuralNet, RunStep)
+runProblemStep p i nn = (newNN, RunStep i cost)
+  where
+    exampleSet = problemExampleSet p
+    forwardSteps = nnForwardSet nn exampleSet
+    al = forwardPropA (last forwardSteps)
+    cost = computeCost al (exampleSetY exampleSet)
+    grads = nnBackward nn forwardSteps exampleSet
+    newNN = updateNNParams nn grads (problemLearningRate p)
diff --git a/test/NeuralNet/CostSpec.hs b/test/NeuralNet/CostSpec.hs
@@ -7,9 +7,9 @@ import NeuralNet.Cost
 costSpec :: SpecWith ()
 costSpec =
   describe "NeuralNet.Cost" $
-    describe "cost" $ do
+    describe "computeCost" $ do
       it "calculates correctly for example" $
         let
           al = fromLists [[0.8, 0.9, 0.4]]
           y = fromLists [[1, 1, 1]]
-        in cost al y `shouldBe` 0.41493159961539694
+        in computeCost al y `shouldBe` 0.41493159961539694