Adding skeleton helper library.

- This library should be added to and expanded.

CMakeLists.txt

@@ -4,7 +4,6 @@ project(EICD
   LANGUAGES CXX)
 
 #--- Declare options -----------------------------------------------------------
-option(CREATE_DOC "Whether or not to create doxygen doc target.")
 option(BUILD_DATA_MODEL "Run podio class generator yaml file" ON)
 
 if(APPLE)
@@ -12,8 +11,6 @@ if(APPLE)
 endif(APPLE)
 
 
-#set(PODIO $ENV{PODIO})
-#set(CMAKE_MODULE_PATH ${PODIO}/lib/cmake/podio)
 find_package(podio 0.11.0 REQUIRED)
 include_directories(${podio_INCLUDE_DIR})
 
@@ -50,6 +47,9 @@ PODIO_GENERATE_DICTIONARY(eicd ${headers}
 set_target_properties(eicd-dictgen PROPERTIES EXCLUDE_FROM_ALL TRUE)
 target_sources(eicd PRIVATE eicd.cxx)
 
+add_subdirectory(source)
+
+
 install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/eicd
   DESTINATION include
   FILES_MATCHING PATTERN *.h
@@ -74,6 +74,8 @@ add_custom_target( doc_doxygen #ALL
   COMMENT "Generating API documentation with Doxygen"
   VERBATIM )
 
+
+
 # -------------------------
 # install library config
 include(CMakePackageConfigHelpers)

source/CMakeLists.txt

+find_package(ROOT REQUIRED COMPONENTS GenVector MathCore)
+
+#ROOT_GENERATE_DICTIONARY(G__NPDetGeoCad
+#  include/TGeoToStep.h
+#  OPTIONS -I${OpenCASCADE_INCLUDE_DIR} 
+#  OPTIONS -I${CMAKE_CURRENT_SOURCE_DIR} 
+#  OPTIONS -I${CMAKE_CURRENT_SOURCE_DIR}/include 
+#  OPTIONS -I${CMAKE_CURRENT_SOURCE_DIR}/src 
+#  LINKDEF include/LinkDef.h
+#  )
+#add_custom_target(G__NPDetGeoCad_ROOTDICT DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/G__NPDetGeoCad.cxx)
+
+add_library(eicd_core SHARED
+  src/helpers.cxx
+  )
+
+target_compile_features(eicd_core
+    PUBLIC cxx_auto_type
+    PUBLIC cxx_trailing_return_types
+    PUBLIC cxx_std_17
+    PRIVATE cxx_variadic_templates
+    )
+
+target_compile_options(eicd_core PRIVATE 
+  -Wno-extra
+  -Wno-ignored-qualifiers
+  -Wno-overloaded-virtual
+  -Wno-shadow)
+
+target_link_libraries(eicd_core 
+  PUBLIC eicd
+  PUBLIC ROOT::GenVector ROOT::MathCore)
+
+target_include_directories(eicd_core 
+  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+  PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+  PUBLIC $<INSTALL_INTERFACE:include>
+  )
+
+install(FILES 
+  include/eicd/helpers.h
+  DESTINATION include/eicd
+  )
+#install(FILES
+#  "${CMAKE_CURRENT_BINARY_DIR}/libNPDetGeoCad.rootmap"
+#  "${CMAKE_CURRENT_BINARY_DIR}/libNPDetGeoCad_rdict.pcm"
+#  DESTINATION lib)
+
+
+install(TARGETS eicd_core
+  EXPORT ${PROJECT_NAME}Targets
+  LIBRARY DESTINATION lib
+  ARCHIVE DESTINATION lib
+  RUNTIME DESTINATION bin
+  INCLUDES DESTINATION include
+  )

source/include/eicd/helpers.h

+#ifndef EICD_HELPERS_HH
+#define EICD_HELPERS_HH
+
+
+#include <algorithm>
+#include <cmath>
+#include <exception>
+#include <limits>
+#include <string>
+#include <vector>
+
+#include <Math/Vector4D.h>
+
+#include "eicd/TrackParametersCollection.h"
+#include "eicd/ReconstructedParticleCollection.h"
+#include "eicd/ReconstructedParticleData.h"
+
+namespace eicd::helpers {
+
+  /** Four momentum from track and mass.
+   * Get a vector of 4-momenta from raw tracking info, using an externally
+   * provided particle mass assumption. 
+   */
+  inline auto momenta_from_tracking(const std::vector<eic::TrackParametersData>& tracks,
+                                    const double                                 mass)
+  {
+    std::vector<ROOT::Math::PxPyPzMVector> momenta{tracks.size()};
+    // transform our raw tracker info into proper 4-momenta
+    std::transform(tracks.begin(), tracks.end(), momenta.begin(), [mass](const auto& track) {
+      // make sure we don't divide by zero
+      if (fabs(track.qOverP) < 1e-9) {
+        return ROOT::Math::PxPyPzMVector{};
+      }
+      const double p  = fabs(1. / track.qOverP);
+      const double px = p * cos(track.phi) * sin(track.theta);
+      const double py = p * sin(track.phi) * sin(track.theta);
+      const double pz = p * cos(track.theta);
+      return ROOT::Math::PxPyPzMVector{px, py, pz, mass};
+    });
+    return momenta;
+  }
+} // namespace eicd::helpers
+#endif

source/src/helpers.cxx

+#include "eicd/helpers.h"
+
+