Merge pull request #2 from daniel4x/xor-example

Added XOR example to examples/

Author: daniel4x

engine/engine.go

@@ -110,6 +110,22 @@ func (v *Value) Backward() {
 	}
 }
 
+func (v *Value) Data() float64 {
+	return v.data
+}
+
+func (v *Value) SetData(data float64) {
+	v.data = data
+}
+
+func (v *Value) Grad() float64 {
+	return v.grad
+}
+
+func (v *Value) ZeroGrad() {
+	v.grad = 0
+}
+
 func (v Value) String() string {
 	return fmt.Sprintf("Value(label=%s, data=%f, children=(%v), op=%s, grad=%f)", v.label, v.data, v.children, v.op, v.grad)
 }
@@ -126,7 +142,7 @@ func validateValue(candidate interface{}) *Value {
 }
 
 // Helper functions to create Value slices and matrices (Tensor like objects)
-func makeValues(data []float64) []*Value {
+func MakeValues(data []float64) []*Value {
 	/**
 	 * Create a slice of Value pointers from a slice of float64.
 	 **/
@@ -137,13 +153,13 @@ func makeValues(data []float64) []*Value {
 	return ans
 }
 
-func makeValueMatrix(data [][]float64) [][]*Value {
+func MakeValueMatrix(data [][]float64) [][]*Value {
 	/**
 	 * Create a matrix of Value pointers from a matrix of float64.
 	 **/
 	ans := make([][]*Value, len(data))
 	for i := 0; i < len(data); i++ {
-		ans[i] = makeValues(data[i])
+		ans[i] = MakeValues(data[i])
 	}
 	return ans
 }

engine/nn.go

@@ -1,6 +1,9 @@
 package engine
 
-import "math/rand"
+import (
+	"fmt"
+	"math/rand"
+)
 
 /**
  * The structs and functions in this file are used to create a simple feedforward neural network (MLP).
@@ -41,6 +44,12 @@ func NewNeuron(in int) *Neuron {
 	return &Neuron{weights: weights, bias: bias}
 }
 
+func (n *Neuron) String() string {
+	ans := "Neuron{"
+	ans += fmt.Sprintf("Weights=%v, ", len(n.weights))
+	return ans + "Bias}"
+}
+
 type Layer struct {
 	neurons []*Neuron
 }
@@ -70,6 +79,15 @@ func NewLayer(in, out int) *Layer {
 	return &Layer{neurons: neurons}
 }
 
+func (l *Layer) String() string {
+	ans := "Layer{\n"
+	for i := 0; i < len(l.neurons); i++ {
+		ans += "\t\t" + l.neurons[i].String() + ",\n"
+	}
+	ans += "\t}"
+	return ans
+}
+
 type MLP struct {
 	layers []*Layer
 }
@@ -106,3 +124,12 @@ func NewMLP(in int, outs []int) *MLP {
 
 	return &MLP{layers: layers}
 }
+
+func (m *MLP) String() string {
+	ans := "MLP{\n"
+	for i := 0; i < len(m.layers); i++ {
+		ans += "\t" + m.layers[i].String() + ",\n"
+	}
+	ans += "}"
+	return ans
+}

engine/nn_test.go

@@ -6,7 +6,7 @@ import (
 )
 
 func TestMLPSimpleScenario(t *testing.T) {
-	x := makeValueMatrix(
+	x := MakeValueMatrix(
 		[][]float64{
 			{2.0, 3.0, -1.0},
 			{3.0, -1.0, 0.5},

examples/xor.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	"fmt"
+	"math"
+
+	e "github.com/daniel4x/GoGrad/engine"
+)
+
+func createXORData() ([][]*e.Value, []float64) {
+	x := [][]float64{
+		{0, 0},
+		{0, 1},
+		{1, 0},
+		{1, 1},
+	}
+	y := []float64{-1, 1, 1, -1} // setting False as -1 and True as 1 just to get a cleaner outputs from the model
+
+	return e.MakeValueMatrix(x), y
+}
+
+func printData(X [][]*e.Value, y []float64) {
+	for i := 0; i < len(X); i++ {
+		fmt.Printf("(%v, %v) -> %v\n", X[i][0].Data(), X[i][1].Data(), y[i])
+	}
+}
+
+func main() {
+	// Create XOR dataset
+	X, y := createXORData()
+	fmt.Println("XOR dataset:")
+	printData(X, y)
+
+	// Define a two-layer MLP with 2 input neurons, 2 hidden layers with 4 neurons each, and 1 output neuron
+	nn := e.NewMLP(2, []int{4, 4, 1})
+	fmt.Println("\nMulti-layer Perceptron Definition:\n", nn)
+
+	// Train the model
+	epochs := 2000
+	alpha := 0.01
+
+	for i := 0; i < epochs; i++ {
+		y_model := make([]*e.Value, len(X))
+
+		// Forward pass
+		// Feed in each data point
+		for j := 0; j < len(X); j++ {
+			y_model[j] = nn.Call(X[j])
+		}
+
+		// Compute the loss
+		loss := y_model[0].Sub(y[0]).Pow(2)
+		for j := 1; j < len(y_model); j++ {
+			loss = loss.Add(y_model[j].Sub(y[j]).Pow(2))
+		}
+
+		// Backward pass
+		// zero the gradients to avoid accumulation between epochs
+		params := nn.Parameters()
+		for j := 0; j < len(params); j++ {
+			params[j].ZeroGrad()
+		}
+
+		loss.Backward() // backward
+
+		// Update the parameters
+		for j := 0; j < len(params); j++ {
+			params[j].SetData(params[j].Data() - alpha*params[j].Grad())
+		}
+
+		if (i+1)%100 == 0 {
+			// Print the loss every 100 epochs
+			fmt.Println("epoch", i, "loss", loss.Data())
+		}
+	}
+
+	// Test the model
+	predictions := make([]float64, len(X))
+	for i := 0; i < len(X); i++ {
+		predictions[i] = nn.Call(X[i]).Data()
+	}
+
+	fmt.Println("\nTesting the model:")
+	for i := 0; i < len(X); i++ {
+		fmt.Printf("(%v, %v) -> Actual: %v Prediction %v\n", X[i][0].Data(), X[i][1].Data(), y[i], predictions[i])
+	}
+
+	// Raise error if the difference between the actual and predicted values is greater than 0.1
+	for i := 0; i < len(X); i++ {
+		if math.Abs(y[i]-predictions[i]) > 0.1 {
+			panic(fmt.Sprintf("\nTest failed: (%v, %v) -> Actual: %v Prediction %v\n", X[i][0].Data(), X[i][1].Data(), y[i], predictions[i]))
+		}
+	}
+}