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ProcMatrix.cc

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// -*- C++ -*-
//
// Package:     MVAComputer
// Class  :     ProcMatrix
// 

// Implementation:
//     Variable processor to apply a matrix transformation to the input
//     variables. An n x m matrix applied to n input variables results in
//     m output variables.
//
// Author:      Christophe Saout
// Created:     Sat Apr 24 15:18 CEST 2007
// $Id: ProcMatrix.cc,v 1.3 2007/07/15 22:31:46 saout Exp $
//

#include <stdlib.h>

#include "PhysicsTools/MVAComputer/interface/VarProcessor.h"
#include "PhysicsTools/MVAComputer/interface/Calibration.h"

using namespace PhysicsTools;

namespace { // anonymous

class ProcMatrix : public VarProcessor {
    public:
        typedef VarProcessor::Registry::Registry<ProcMatrix,
                                        Calibration::ProcMatrix> Registry;

        ProcMatrix(const char *name,
                   const Calibration::ProcMatrix *calib,
                   const MVAComputer *computer);
        virtual ~ProcMatrix() {}      

        virtual void configure(ConfIterator iter, unsigned int n);
        virtual void eval(ValueIterator iter, unsigned int n) const;

    private:
        class Matrix {
            public:
                inline Matrix(const Calibration::Matrix *calib) :
                        rows(calib->rows), cols(calib->columns),
                        coeffs(calib->elements) {}

                inline unsigned int getRows() const { return rows; }
                inline unsigned int getCols() const { return cols; }

                inline double operator () (unsigned int row,
                                           unsigned int col) const
                { return coeffs[row * cols + col]; }

            private:
                unsigned int            rows;
                unsigned int            cols;
                std::vector<double>     coeffs;
        };

        Matrix  matrix;
};

static ProcMatrix::Registry registry("ProcMatrix");

ProcMatrix::ProcMatrix(const char *name,
                       const Calibration::ProcMatrix *calib,
                       const MVAComputer *computer) :
        VarProcessor(name, calib, computer),
        matrix(&calib->matrix)
{
}

void ProcMatrix::configure(ConfIterator iter, unsigned int n)
{
        if (n != matrix.getCols())
                return;

        for(unsigned int col = 0; col < matrix.getCols(); col++)
                iter++(Variable::FLAG_NONE);

        for(unsigned int row = 0; row < matrix.getRows(); row++)
                iter << Variable::FLAG_NONE;
}

void ProcMatrix::eval(ValueIterator iter, unsigned int n) const
{
        double *sums = (double*)alloca(matrix.getRows() * sizeof(double));
        for(unsigned int row = 0; row < matrix.getRows(); row++)
                sums[row] = 0.0;

        for(unsigned int col = 0; col < matrix.getCols(); col++) {
                double val = *iter++;
                for(unsigned int row = 0; row < matrix.getRows(); row++)
                        sums[row] += matrix(row, col) * val;
        }

        for(unsigned int row = 0; row < matrix.getRows(); row++)
                iter(sums[row]);
}

} // anonymous namespace

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