initial commit

.gitignore

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+bin/
+.settings/
+.cache
+.classpath

.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>scala-nnetworks</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.scala-ide.sdt.core.scalabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.scala-ide.sdt.core.scalanature</nature>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>

src/nnetworks/NNetwork.scala

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+package nnetworks
+
+object Functions {
+  def roundedSigmoid(v: Double): Double = math.round(1.0 / (1.0 + math.exp(-v)))
+}
+
+/**
+ * layer is a two dimensional array of doubles - weights
+ */
+class Layer(weights: Array[Array[Double]]) {
+
+  /**
+   * Fastest implementation based on http://blog.scala4java.com/2011/12/matrix-multiplication-in-scala-single.html
+   */
+  def multiThreadedIdiomatic(m1: Array[Double], m2: Array[Array[Double]]) = {
+    val res = Array.fill[Double](m2(0).length)(0.0)
+    for (
+      col <- (0 until m2(0).length).par;
+      i <- 0 until m1.par.length
+    ) {
+      res(col) += m1(i) * m2(i)(col)
+    }
+    res
+  }
+
+  def applyInputs(input: Array[Double], fun: Double => Double): Array[Double] = {
+    multiThreadedIdiomatic(input, weights) map (fun(_))
+  }
+
+  def applyInputs(input: Array[Double]): Array[Double] = {
+    multiThreadedIdiomatic(input, weights)
+  }
+
+}

test/nnetworks/NetworkTestSuite.scala

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+package nnetworks
+
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+import org.scalatest.FunSuite
+
+/**
+ * This class is a test suite for the methods in object FunSets. To run
+ * the test suite, you can either:
+ *  - run the "test" command in the SBT console
+ *  - right-click the file in eclipse and chose "Run As" - "JUnit Test"
+ */
+@RunWith(classOf[JUnitRunner])
+class NetworkTestSuite extends FunSuite {
+
+    test("Test AND network implemented") {
+    val weights: Array[Array[Double]] = Array(Array(-30.0), Array(20), Array(20))
+    val layer = new Layer(weights)
+
+    assert(layer.applyInputs(Array(1., 0., 0.)) === Array(-30.))
+    assert(layer.applyInputs(Array(1., 0., 1.)) === Array(-10.))
+    assert(layer.applyInputs(Array(1., 1., 0.)) === Array(-10.))
+    assert(layer.applyInputs(Array(1., 1., 1.)) === Array(10.))
+
+  }
+
+
+  test("Test AND network implemented with activation function") {
+    val weights: Array[Array[Double]] = Array(Array(-30.0), Array(20), Array(20))
+    val layer = new Layer(weights)
+
+    assert(layer.applyInputs(Array(1., 0., 0.),Functions.roundedSigmoid ) === Array(0))
+    assert(layer.applyInputs(Array(1., 0., 1.), Functions.roundedSigmoid) === Array(0))
+    assert(layer.applyInputs(Array(1., 1., 0.), Functions.roundedSigmoid) === Array(0))
+    assert(layer.applyInputs(Array(1., 1., 1.), Functions.roundedSigmoid) === Array(1))
+
+  }
+
+  test("Test XOR network implemented") {
+    val weights: Array[Array[Double]] = Array(Array(-30.0, 10.), Array(20, -20.), Array(20, -10.))
+    val layer = new Layer(weights)
+
+    assert(layer.applyInputs(Array(1., 0., 0.), Functions.roundedSigmoid) === Array(0, 1))
+    assert(layer.applyInputs(Array(1., 0., 1.), Functions.roundedSigmoid) === Array(0, 1))
+    assert(layer.applyInputs(Array(1., 1., 0.),Functions.roundedSigmoid) === Array(0, 0))
+    assert(layer.applyInputs(Array(1., 1., 1.), Functions.roundedSigmoid) === Array(1, 0))
+
+  }
+
+  test("Test sigmoid funciton"){
+    assert(Functions.roundedSigmoid(-4) === 0)
+    assert(Functions.roundedSigmoid(-1) === 0)
+    assert(Functions.roundedSigmoid(0) === 1)
+    assert(Functions.roundedSigmoid(1) === 1)
+    assert(Functions.roundedSigmoid(4) === 1)
+  }
+
+}