LinearCombinator.cc

/*
 *  MoMEMta: a modular implementation of the Matrix Element Method
 *  Copyright (C) 2016  Universite catholique de Louvain (UCL), Belgium
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <momemta/ParameterSet.h>
#include <momemta/Module.h>
#include <momemta/Types.h>
#include <momemta/Utils.h>

#include <stdexcept>

template<typename T>
class LinearCombinator: public Module {
    public:

        LinearCombinator(PoolPtr pool, const ParameterSet& parameters): Module(pool, parameters.getModuleName()) {
            auto tags = parameters.get<std::vector<InputTag>>("inputs");
            for (auto& v: tags)
                m_terms.push_back(get<T>(v));

            m_coefficients = parameters.get<std::vector<double>>("coefficients");

            if (m_coefficients.size() == 0 || m_terms.size() == 0){
                auto exception = std::invalid_argument("Tried to call LinearCombinator with an empty input.");
                LOG(fatal) << exception.what();
                throw exception;
            }
            if (m_coefficients.size() != m_terms.size()){
                auto exception = std::invalid_argument("The Term and Coefficient lists passed to LinearCombinator have different sizes.");
                LOG(fatal) << exception.what();
                throw exception;
            }
        };

        virtual Status work() override {

            T temp_result = m_coefficients[0] * *m_terms[0];
            for (std::size_t i = 1; i < m_terms.size(); i++)
                temp_result += m_coefficients[i] * *m_terms[i];

            *output = temp_result;

            return Status::OK;
        }

    private:

        // Inputs
        std::vector<double> m_coefficients;
        std::vector<Value<T>> m_terms;

        // Outputs
        std::shared_ptr<T> output = produce<T>("output");
};

REGISTER_MODULE_NAME("VectorLinearCombinator", LinearCombinator<LorentzVector>)
        .Inputs("inputs")
        .Output("output")
        .Attr("coefficients:list(double)");

REGISTER_MODULE_NAME("DoubleLinearCombinator", LinearCombinator<double>)
        .Inputs("inputs")
        .Output("output")
        .Attr("coefficients:list(double)");

REGISTER_MODULE_NAME("IntLinearCombinator", LinearCombinator<int64_t>)
        .Inputs("inputs")
        .Output("output")
        .Attr("coefficients:list(double)");