TRestComponentFormula.cxx

/*************************************************************************
 * This file is part of the REST software framework.                     *
 *                                                                       *
 * Copyright (C) 2016 GIFNA/TREX (University of Zaragoza)                *
 * For more information see https://gifna.unizar.es/trex                 *
 *                                                                       *
 * REST 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.                                   *
 *                                                                       *
 * REST 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 a copy of the GNU General Public License along with   *
 * REST in $REST_PATH/LICENSE.                                           *
 * If not, see https://www.gnu.org/licenses/.                            *
 * For the list of contributors see $REST_PATH/CREDITS.                  *
 *************************************************************************/
 
#include "TRestComponentFormula.h"
 
#include <numeric>
 
#include "TKey.h"
 
ClassImp(TRestComponentFormula);
 
TRestComponentFormula::TRestComponentFormula() { Initialize(); }
 
TRestComponentFormula::TRestComponentFormula(const char* cfgFileName, const std::string& name)
    : TRestComponent(cfgFileName) {
    Initialize();
 
    LoadConfigFromFile(fConfigFileName, name);
 
    if (GetVerboseLevel() >= TRestStringOutput::REST_Verbose_Level::REST_Info) PrintMetadata();
}
 
TRestComponentFormula::~TRestComponentFormula() {}
 
void TRestComponentFormula::Initialize() {
    TRestComponent::Initialize();
 
    SetSectionName(this->ClassName());
 
    FillHistograms();
}
 
Double_t TRestComponentFormula::GetFormulaRate(std::vector<Double_t> point) {
    if (fVariables.size() != point.size()) {
        RESTError << "Point should have same dimensions as number of variables!" << RESTendl;
        return 0;
    }
 
    Double_t result = 0;
    for (auto& formula : fFormulas) {
        for (size_t n = 0; n < fVariables.size(); n++) formula.SetParameter(fVariables[n].c_str(), point[n]);
 
        result += formula.EvalPar(nullptr);
    }
 
    Double_t normFactor = 1;
    for (size_t n = 0; n < GetDimensions(); n++) {
        normFactor *= (fRanges[n].Y() - fRanges[n].X()) / fNbins[n];
    }
 
    return normFactor * result / units(fUnits);
}
 
void TRestComponentFormula::FillHistograms() {
    if (fFormulas.empty()) return;
 
    RESTInfo << "Generating N-dim histogram for " << GetName() << RESTendl;
 
    TString hName = "formula";
 
    Int_t* bins = new Int_t[fNbins.size()];
    Double_t* xlow = new Double_t[fNbins.size()];
    Double_t* xhigh = new Double_t[fNbins.size()];
 
    for (size_t n = 0; n < fNbins.size(); n++) {
        bins[n] = fNbins[n];
        xlow[n] = fRanges[n].X();
        xhigh[n] = fRanges[n].Y();
    }
 
    THnD* hNd = new THnD(hName, hName, fNbins.size(), bins, xlow, xhigh);
 
    // Calculate the bin width in each dimension
    std::vector<double> binWidths;
    for (size_t i = 0; i < fNbins.size(); ++i) {
        double width = static_cast<double>(xhigh[i] - xlow[i]) / bins[i];
        binWidths.push_back(width);
    }
 
    // Nested loop to iterate over each bin and print its center
    std::vector<int> binIndices(fNbins.size(), 0);  // Initialize bin indices to 0 in each dimension
 
    bool carry = false;
    while (!carry) {
        // Calculate the center of the current bin in each dimension
        std::vector<double> binCenter;
        for (size_t i = 0; i < fNbins.size(); ++i)
            binCenter.push_back(xlow[i] + (binIndices[i] + 0.5) * binWidths[i]);
 
        hNd->Fill(binCenter.data(), GetFormulaRate(binCenter));
 
        // Update bin indices for the next iteration
        carry = true;
        for (size_t i = 0; i < fNbins.size(); ++i) {
            binIndices[i]++;
            if (binIndices[i] < bins[i]) {
                carry = false;
                break;
            }
            binIndices[i] = 0;
        }
    }
 
    fNodeDensity.clear();
    fNodeDensity.push_back(hNd);
    fActiveNode = 0;  // For the moment only 1-node!
}
 
void TRestComponentFormula::PrintMetadata() {
    TRestComponent::PrintMetadata();
 
    RESTMetadata << " " << RESTendl;
    RESTMetadata << "Formula units: " << fUnits << RESTendl;
 
    if (!fFormulas.empty()) {
        RESTMetadata << " " << RESTendl;
        RESTMetadata << " == Contributions implemented inside the component ==" << RESTendl;
 
        for (const auto& x : fFormulas)
            RESTMetadata << "- " << x.GetName() << " = " << x.GetExpFormula() << RESTendl;
 
        RESTMetadata << " " << RESTendl;
    }
 
    RESTMetadata << "----" << RESTendl;
}
 
void TRestComponentFormula::InitFromConfigFile() {
    TRestComponent::InitFromConfigFile();
 
    if (!fFormulas.empty()) return;
 
    auto ele = GetElement("formula");
    while (ele != nullptr) {
        std::string name = GetParameter("name", ele, "");
        std::string expression = GetParameter("expression", ele, "");
 
        if (expression.empty()) {
            RESTWarning << "TRestComponentFormula::InitFromConfigFile. Invalid formula" << RESTendl;
        } else {
            TFormula formula(name.c_str(), expression.c_str());
 
            for (Int_t n = 0; n < formula.GetNpar(); n++) {
                if (std::find(fVariables.begin(), fVariables.end(), formula.GetParName(n)) ==
                    fVariables.end()) {
                    RESTError << "Variable : " << formula.GetParName(n) << " not found in component! "
                              << RESTendl;
                    RESTError << "TRestComponentFormula evaluation will lead to wrong results!" << RESTendl;
                }
            }
 
            for (const auto& varName : fVariables) formula.SetParameter(varName.c_str(), 0.0);
 
            fFormulas.push_back(formula);
        }
 
        ele = GetNextElement(ele);
    }
}