source: proiecte/ParallelANN/BCMToolbox/Hebbian2.cs @ 171

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

namespace BCMToolbox
{

    #region Hebbian2 Base
    public abstract class SynchronousHebbian2Network : FixedTraceableNetwork
    {
        double[] __intermediaryOutputs = null;
        

        protected Func<double, double> __activation = MathToolbox.Sigmoid;
        protected Func<double, double> __activation_inverse = MathToolbox.InverseSigmoid;

        public SynchronousHebbian2Network(int neuronCount, int newID)
            : base(neuronCount, newID)
        {
            __intermediaryOutputs = new double[neuronCount];
        }

      
        public override string Identification
        {
            get
            {
                return String.Format("Hebb2 Layer #{0}", this.UID);
            }
        }

        public virtual double Inertia
        {
            get
            {
                return 0.02;
            }
        }

        public virtual double OutputDecay
        {
            get
            {
                return 0.85;
            }
        }

        protected abstract double WeightModificationKernel(double weight, double input, double output);
       

        public virtual bool HasNormalizedWeights
        {
            get
            {
                return false;
            }
        }

        public virtual bool HasNormalizedInputs
        {
            get
            {
                return false;
            }
        }

       

        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];
            }

            if(HasNormalizedInputs)
                NormalizePotentials(2.0);
            
            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];
                __intermediaryOutputs[i] = __activation(__intermediaryOutputs[i]);
            }

            if (HasNormalizedInputs)
            {
                double[] temp = __potentials;
                __potentials = __intermediaryOutputs;
                NormalizePotentials(2.0);
                __potentials = temp;
            }

            // 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;

                        __weights[i,j] = WeightModificationKernel(__weights[i, j], __potentials[i], __intermediaryOutputs[j]);


                        System.Diagnostics.Debug.Assert(!double.IsNaN(__weights[i, j]));
                        System.Diagnostics.Debug.Assert(!double.IsInfinity(__weights[i, j]));


                        
                    }
                
                if(HasNormalizedWeights)
                    NormalizeWeights(2.0);

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

        public override void Initialize(Func<int, int, double> initializerWeights, Func<int, double> initializerPotentials)
        {
            base.Initialize(initializerWeights, initializerPotentials);
            if(HasNormalizedInputs)
                NormalizePotentials(2.0);

            if (HasNormalizedWeights)
                NormalizeWeights(2.0);
        }
    }

    #endregion

    // 0->0 (--), 1->0 (+), 1->1 (++), 0->1 (-)
    #region Model 01 
    public class Model01 : SynchronousHebbian2Network
    {
        const double EXC_THRESHOLD = 0.5;
        const double MEMORY_CONSTANT = 2.5;
        public Model01(int neuronCount, int newID)
            : base(neuronCount, newID)
        {
        }

        protected override double WeightModificationKernel(double weight, double input, double output)
        {
            double unpacked = __activation_inverse(weight);
            unpacked += Math.Sign(input - EXC_THRESHOLD)*Math.Pow(Math.Abs(input - EXC_THRESHOLD), MEMORY_CONSTANT) * (1 - Math.Abs(input - output)) * Inertia;
            unpacked = __activation(unpacked);
            

            
            return unpacked;
        }

        public override double Inertia
        {
            get
            {
                return 0.02;
            }
        }
    }
    #endregion
}