LMSCanceller.cpp

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#include "LMSCanceller.h"
#include "FatalException.h"
#include <iostream>
#include <iterator>
using namespace std;

namespace gplib
  {

    LMSCanceller::LMSCanceller(const int inputsize) :
      LSSOFilter(inputsize), mu(1)
      {
      }

    LMSCanceller::LMSCanceller(const int inputsize, const double Mymu) :
      LSSOFilter(inputsize), mu(Mymu)
      {
      }

    LMSCanceller::~LMSCanceller()
      {
      }

    void LMSCanceller::AdaptFilter(const gplib::rvec &Input,
        const gplib::rvec &Desired)
      {
        if (Input.size() != GetInputLength() || Input.size() != GetWeights().size()
            || Desired.size() != GetOutputLength())
          throw FatalException("Input or Desired do not have expected size !");

        SetEpsilon(Desired - GetFilterOutput()); //Calculate the last prediction error
        double step = ublas::prec_inner_prod(Input, Input); //the power of the input data
        const double delta = 0.0001; // We introduce delta to improve stability for small values
        step = mu / (step + delta); //here see Haykin, p 323
        SetWeights() += 2.0 * step * GetEpsilon()(0) * Input; //update Filter based on prediction error
      }
  }