Upstream FastJet algorithm from MuonCollider fork

CMakeLists.txt

@@ -26,6 +26,7 @@ set(${PROJECT_NAME}_VERSION_MINOR 4)
 set(${PROJECT_NAME}_VERSION_PATCH 0)
 
 set(${PROJECT_NAME}_VERSION "${${PROJECT_NAME}_VERSION_MAJOR}.${${PROJECT_NAME}_VERSION_MINOR}.${${PROJECT_NAME}_VERSION_PATCH}")
+set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 
 option(BUILD_TRACKING "Build conformal tracking" ON)
 
@@ -37,6 +38,8 @@ find_package(k4FWCore 1.4 REQUIRED)
 find_package(ROOT REQUIRED COMPONENTS RIO Tree)
 find_package(k4SimGeant4 REQUIRED)
 
+find_package(FastJet REQUIRED)
+
 include(cmake/Key4hepConfig.cmake)
 
 include(GNUInstallDirs)

README.md

@@ -1,3 +1,14 @@
 # k4Reco
 
 Gaudi algorithms for reconstruction using EDM4hep natively.
+
+## Example steering files
+
+Example steering files that show how to configure and run the algorithms live in the
+`options` directory of the corresponding subfolder of [`k4Reco`](k4Reco), e.g.
+[`k4Reco/Tracking/options`](k4Reco/Tracking/options). The ones that are only used to
+run and validate the algorithms in the tests are kept next to the tests instead, e.g.
+[`test/FastJet`](test/FastJet) for the `FastJetAlg`.
+
+In either case these files are examples and the configurations that we use for testing,
+they are not blessed production configurations.

cmake/FindFastJet.cmake

@@ -0,0 +1,70 @@
+# - Locate FastJet library (including fastjet-contrib)
+# Defines:
+#
+#  FASTJET_FOUND
+#  FASTJET_INCLUDE_DIR
+#  FASTJET_INCLUDE_DIRS (not cached)
+#  FASTJET_LIBRARY
+#  FASTJET_LIBRARIES (not cached)
+#  FASTJET_LIBRARY_DIRS (not cached)
+
+find_path(FASTJET_INCLUDE_DIR fastjet/version.hh
+          HINTS $ENV{FASTJET_ROOT_DIR}/include ${FASTJET_ROOT_DIR}/include)
+
+# fastjet-contrib provides the ValenciaPlugin. It is a separate package that may be
+# installed either into the FastJet prefix or into one of its own
+find_path(FASTJET_CONTRIB_INCLUDE_DIR fastjet/contrib/ValenciaPlugin.hh
+          HINTS $ENV{FJCONTRIB_ROOT_DIR}/include ${FJCONTRIB_ROOT_DIR}/include
+                $ENV{FASTJET_ROOT_DIR}/include ${FASTJET_ROOT_DIR}/include
+                ${FASTJET_INCLUDE_DIR})
+
+find_library(FASTJET_LIBRARY NAMES fastjet
+             HINTS $ENV{FASTJET_ROOT_DIR}/lib ${FASTJET_ROOT_DIR}/lib)
+
+find_library(FASTJETPLUGINS_LIBRARY NAMES fastjetplugins
+             HINTS $ENV{FASTJET_ROOT_DIR}/lib ${FASTJET_ROOT_DIR}/lib)
+
+# Needed by fastjet-contrib, which uses the background estimators and Recluster
+find_library(FASTJETTOOLS_LIBRARY NAMES fastjettools
+             HINTS $ENV{FASTJET_ROOT_DIR}/lib ${FASTJET_ROOT_DIR}/lib)
+
+find_library(FASTJETCONTRIB_LIBRARY NAMES fastjetcontribfragile fastjetcontrib
+             HINTS $ENV{FJCONTRIB_ROOT_DIR}/lib ${FJCONTRIB_ROOT_DIR}/lib
+                   $ENV{FASTJET_ROOT_DIR}/lib ${FASTJET_ROOT_DIR}/lib)
+
+find_library(SISCONE_LIBRARY NAMES siscone
+             HINTS $ENV{FASTJET_ROOT_DIR}/lib ${FASTJET_ROOT_DIR}/lib)
+
+find_library(SISCONE_SPHERICAL_LIBRARY NAMES siscone_spherical
+             HINTS $ENV{FASTJET_ROOT_DIR}/lib ${FASTJET_ROOT_DIR}/lib)
+
+# handle the QUIETLY and REQUIRED arguments and set FASTJET_FOUND to TRUE if
+# all listed variables are TRUE
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(FastJet DEFAULT_MSG FASTJET_INCLUDE_DIR FASTJET_LIBRARY
+                                  FASTJET_CONTRIB_INCLUDE_DIR FASTJETCONTRIB_LIBRARY
+                                  FASTJETTOOLS_LIBRARY)
+
+mark_as_advanced(FASTJET_FOUND FASTJET_INCLUDE_DIR FASTJET_LIBRARY FASTJET_CONTRIB_INCLUDE_DIR
+                 FASTJETPLUGINS_LIBRARY FASTJETTOOLS_LIBRARY FASTJETCONTRIB_LIBRARY
+                 SISCONE_LIBRARY SISCONE_SPHERICAL_LIBRARY)
+
+set(FASTJET_INCLUDE_DIRS ${FASTJET_INCLUDE_DIR} ${FASTJET_CONTRIB_INCLUDE_DIR})
+list(REMOVE_DUPLICATES FASTJET_INCLUDE_DIRS)
+# libfastjetcontribfragile.so is built without linking the FastJet libraries it uses (hence
+# "fragile"): it carries undefined references to fastjettools, and has no DT_NEEDED of its
+# own to satisfy them. Nothing in k4Reco references fastjettools directly, so where
+# --as-needed is the compiler default (Debian/Ubuntu) the linker drops it from our DT_NEEDED
+# and loading the plugin then fails with
+#   undefined symbol: _ZTIN7fastjet28JetMedianBackgroundEstimatorE
+# Pin the pair with --no-as-needed, and keep dependents before dependencies
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  set(FASTJET_CONTRIB_LINK "-Wl,--push-state,--no-as-needed" ${FASTJETCONTRIB_LIBRARY}
+                           ${FASTJETTOOLS_LIBRARY} "-Wl,--pop-state")
+else()
+  set(FASTJET_CONTRIB_LINK ${FASTJETCONTRIB_LIBRARY} ${FASTJETTOOLS_LIBRARY})
+endif()
+
+set(FASTJET_LIBRARIES ${FASTJET_CONTRIB_LINK} ${FASTJETPLUGINS_LIBRARY}
+                      ${SISCONE_SPHERICAL_LIBRARY} ${SISCONE_LIBRARY} ${FASTJET_LIBRARY})
+get_filename_component(FASTJET_LIBRARY_DIRS ${FASTJET_LIBRARY} PATH)

k4Reco/CMakeLists.txt

@@ -19,6 +19,7 @@ limitations under the License.
 
 set(sources
   DDPlanarDigi/components/DDPlanarDigi.cpp
+  FastJet/src/FastJetAlg.cpp
   GaudiLumiCalClusterer/components/GaudiLumiCalClusterer.cpp
   GaudiLumiCalClusterer/src/LumiCalClusterer.cpp
   GaudiLumiCalClusterer/src/LumiCalClusterer_getCalHits.cpp
@@ -44,6 +45,7 @@ set(libs
         ROOT::Core
         ROOT::MathCore
         ROOT::Tree
+        ${FASTJET_LIBRARIES}
 )
 
 if(BUILD_TRACKING)
@@ -123,6 +125,11 @@ target_include_directories(k4RecoPlugins PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/Tracking/include>
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
 
+# Only the FastJetAlg sources use these, nothing links against a Gaudi module
+target_include_directories(k4RecoPlugins PRIVATE
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/FastJet/include>)
+target_include_directories(k4RecoPlugins SYSTEM PRIVATE ${FASTJET_INCLUDE_DIRS})
+
 if(BUILD_TRACKING)
   target_include_directories(k4RecoPlugins
     PUBLIC
@@ -136,7 +143,12 @@ if(BUILD_TRACKING)
   )
 endif()
 
-install(TARGETS GaudiTrkUtils k4RecoPlugins
+set(install_targets k4RecoPlugins)
+if(BUILD_TRACKING)
+  list(APPEND install_targets GaudiTrkUtils)
+endif()
+
+install(TARGETS ${install_targets}
   EXPORT k4RecoTargets
   RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT bin
   LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}" COMPONENT shlib

k4Reco/FastJet/include/EClusterMode.h

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2020-2024 Key4hep-Project.
+ *
+ * This file is part of Key4hep.
+ * See https://key4hep.github.io/key4hep-doc/ for further info.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef K4RECO_FASTJET_ECLUSTERMODE_H
+#define K4RECO_FASTJET_ECLUSTERMODE_H
+
+#include <iostream>
+
+// The enum, name and value of the enum for the Cluster Mode
+namespace k4Reco::FastJet {
+enum EClusterMode {
+  NONE = 0,
+  FJ_exclusive_yCut = 1,     // exclusive clustering mode implemented in FastJet
+  FJ_exclusive_nJets = 2,    // exclusive clustering mode implemented in FastJet
+  FJ_inclusive = 4,          // inclusive "-"
+  OWN_inclusiveIteration = 8 // use FJ inclusive Clustering, but iterate until we have the desired number of jets
+};
+std::ostream& operator<<(std::ostream& out, EClusterMode& m) {
+  switch (m) {
+  case OWN_inclusiveIteration:
+    out << "InclusiveIterativeNJets";
+    break;
+  case FJ_inclusive:
+    out << "Inclusive";
+    break;
+  case FJ_exclusive_nJets:
+    out << "ExclusiveNJets";
+    break;
+  case FJ_exclusive_yCut:
+    out << "ExclusiveYCut";
+    break;
+  default:
+    out << "unknown";
+    break;
+  }
+  return out;
+}
+
+} // namespace k4Reco::FastJet
+#endif