Forward Tagger Energy Correction Function

CODEOWNERS

@@ -1,6 +1,7 @@
 #################################################################################
 # GitHub Handle                Name
 # =============                ====
+# @asligonulacar               Asli Acar
 # @c-dilks                     Christopher Dilks
 # @RichCap                     Richard Capobianco
 # @rtysonCLAS12                Richard Tyson
@@ -10,4 +11,5 @@
 src/iguana/algorithms/clas12/MomentumCorrection/* @RichCap @c-dilks
 src/iguana/algorithms/clas12/ZVertexFilter/* @rtysonCLAS12
 src/iguana/algorithms/clas12/SectorFinder/* @rtysonCLAS12
+src/iguana/algorithms/clas12/FTEnergyCorrection/* @asligonulacar
 src/iguana/services/YAMLReader.* @rtysonCLAS12 @c-dilks

src/iguana/algorithms/clas12/FTEnergyCorrection/Algorithm.cc

@@ -0,0 +1,43 @@
+#include "Algorithm.h"
+
+namespace iguana::clas12 {
+  REGISTER_IGUANA_ALGORITHM(FTEnergyCorrection);
+
+  void FTEnergyCorrection::Start(hipo::banklist& banks) {
+    b_ft_particle = GetBankIndex(banks, "RECFT::Particle");
+    electron_mass = particle::mass.at(particle::electron);
+  }
+
+  void FTEnergyCorrection::Run(hipo::banklist& banks) const {
+    auto& ftParticleBank = GetBank(banks, b_ft_particle, "RECFT::Particle");
+    ShowBank(ftParticleBank, Logger::Header("INPUT FT PARTICLES"));
+    for(auto const& row : ftParticleBank.getRowList()) {
+      if(ftParticleBank.getInt("pid", row) == particle::PDG::electron) {
+        auto px = ftParticleBank.getFloat("px", row);
+        auto py = ftParticleBank.getFloat("py", row);
+        auto pz = ftParticleBank.getFloat("pz", row);
+        auto E = std::hypot(std::hypot(px, py, pz), electron_mass);
+        auto [px_new, py_new, pz_new, E_new] = Transform(px, py, pz, E);
+        ftParticleBank.putFloat("px", row, px_new);
+        ftParticleBank.putFloat("py", row, py_new);
+        ftParticleBank.putFloat("pz", row, pz_new);
+      }
+    }
+    ShowBank(ftParticleBank, Logger::Header("OUTPUT FT PARTICLES"));
+  }
+
+  vector4_t  FTEnergyCorrection::Transform(
+      vector_element_t px,
+      vector_element_t py,
+      vector_element_t pz,
+      vector_element_t E) const
+  {
+    vector_element_t rho = std::hypot(px, py, pz);
+    vector_element_t E_new = E +  0.0208922 + 0.050158*E - 0.0181107*pow(E,2) + 0.00305671*pow(E,3) - 0.000178235*pow(E,4);
+    return { E_new*(px/rho), E_new*(py/rho), E_new*(pz/rho), E_new };
+  }
+
+  void FTEnergyCorrection::Stop() {
+  }
+
+}

src/iguana/algorithms/clas12/FTEnergyCorrection/Algorithm.h

@@ -0,0 +1,45 @@
+#pragma once
+
+#include "iguana/algorithms/Algorithm.h"
+#include "iguana/algorithms/TypeDefs.h"
+
+namespace iguana::clas12 {
+
+  /// @brief_algo Forward Tagger energy correction
+  ///
+  /// @begin_doc_algo{Transformer}
+  /// @input_banks{RECFT::Particle}
+  /// @output_banks{RECFT::Particle}
+  /// @end_doc
+  class FTEnergyCorrection : public Algorithm {
+
+    DEFINE_IGUANA_ALGORITHM(FTEnergyCorrection, clas12::FTEnergyCorrection)
+
+    public:
+
+      void Start(hipo::banklist& banks) override;
+      void Run(hipo::banklist& banks) const override;
+      void Stop() override;
+
+      /// @action_function{scalar transformer}
+      /// Transformation function that returns 4-vector of electron with corrected energy for the Forward Tagger.
+      /// Currently only validated for Fall 2018 outbending data.
+      /// @param px @f$p_x@f$
+      /// @param py @f$p_y@f$
+      /// @param pz @f$p_z@f$
+      /// @param E @f$E@f$
+      /// @returns an electron 4-vector with the corrected energy for the Forward Tagger.
+      vector4_t Transform(
+          vector_element_t px,
+          vector_element_t py,
+          vector_element_t pz,
+          vector_element_t E) const;
+
+    private:
+
+      hipo::banklist::size_type b_ft_particle;
+      double electron_mass;
+
+  };
+
+}

src/iguana/algorithms/meson.build

@@ -65,6 +65,13 @@ algo_dict += [
     'has_validator': false,
     'test_args': { 'banks': ['REC::Particle'] },
   },
+  {
+    'name': 'clas12::FTEnergyCorrection',
+    'has_config': false,
+    'has_c_bindings': false,
+    'has_validator': false,
+    'test_args': { 'banks': ['RECFT::Particle'] },
+  },
   {
     'name': 'clas12::MomentumCorrection',
     'has_config': false,