source: proiecte/ParallelANN/BCMToolbox/Oja.cs @ 171

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BCMToolbox
{
    public class SynchronousOjaNetwork : FixedTraceableNetwork
    {
        double[] __intermediaryOutputs = null;
        double __inertia = 0.005;
        public SynchronousOjaNetwork(int neuronCount, int newID)
            : base(neuronCount, newID)
        {
            __intermediaryOutputs = new double[neuronCount];
        }

      
        public override string Identification
        {
            get
            {
                return String.Format("Oja Layer #{0}", this.UID);
            }
        }

        public double Inertia
        {
            get
            {
                return __inertia;
            }
            set
            {
                __inertia = value;
            }
        }

       

        public override void ApplyInputs(double[] inputs)
        {
            lock (SyncRoot)
            {
                if (inputs == null)
                    throw new ArgumentNullException();

                if (inputs.Length != this.Count)
                    throw new ArgumentException("Invalid input size. Expected: ", this.Count.ToString());

                for (int i = 0; i < this.Count; i++)
                    __potentials[i] += inputs[i];
            }
            
            base.ApplyInputs(inputs);
        }


        public override void Propagate()
        {
            // calculate outputs
            for (int i = 0; i < this.Count; i++)
            {
                __intermediaryOutputs[i] = 0.0;
                for (int j = 0; j < this.Count; j++)
                    if ((i != j) && !double.IsNaN(__weights[j, i]))
                        __intermediaryOutputs[i] += __weights[j, i] * __potentials[j];
            }

            // update weights and lock outputs
            lock (SyncRoot)
            {               
                for (int i = 0; i < this.Count; i++)
                    for (int j = 0; j < this.Count; j++)
                    {
                        if ((i == j) || double.IsNaN(__weights[i, j]))
                            continue;

                        double delta = __intermediaryOutputs[j];
                        delta *= __inertia;
                        delta *= __potentials[i] - __intermediaryOutputs[j] * __weights[i, j];

                        System.Diagnostics.Debug.Assert(!double.IsNaN(delta));
                        System.Diagnostics.Debug.Assert(!double.IsInfinity(delta));

                        __weights[i, j] += delta;
                    }
                //NormalizeWeights(2.0);

                for (int i = 0; i < this.Count; i++)
                    __potentials[i] = __intermediaryOutputs[i];
            }
           
            base.Propagate();
        }

        public override void Initialize(Func<int, int, double> initializerWeights, Func<int, double> initializerPotentials)
        {
            base.Initialize(initializerWeights, initializerPotentials);
            NormalizeWeights(2.0);
        }
    }

    
}