Add comments for uniqueID svc (#83)

* Add Unique ID generation service
key4hep · May 20, 2022 · 73edff3 · 73edff3
1 parent d6555ad
commit 73edff3
Show file tree

Hide file tree

Showing 5 changed files with 33 additions and 10 deletions.
diff --git a/k4FWCore/components/UniqueIDGenSvc.cpp b/k4FWCore/components/UniqueIDGenSvc.cpp
@@ -11,18 +11,22 @@ StatusCode UniqueIDGenSvc::initialize() {
 }
 
 const size_t bits32 = std::numeric_limits<uint32_t>::digits;
+const size_t bits64 = std::numeric_limits<uint64_t>::digits;
 const size_t bitsSizeT = std::numeric_limits<size_t>::digits;
 
 size_t UniqueIDGenSvc::getUniqueID(
-  uint32_t evt_num, uint32_t run_num, std::string name) const 
+  uint32_t evt_num, uint32_t run_num, const std::string& name) const
 {
-  std::bitset<bits32> event_num_bits(evt_num);
-  std::bitset<bits32> run_num_bits(run_num);
+  std::bitset<bits64> seed_bits(this->m_seed);
+  std::bitset<bits32> event_num_bits(evt_num), run_num_bits(run_num);
   size_t str_hash = std::hash<std::string>{}(name);
   std::bitset<bitsSizeT> name_bits(str_hash);
 
+  std::bitset<bits64+bits32+bits32+bitsSizeT> combined_bits(
+    seed_bits.to_string() +
+    event_num_bits.to_string() +
+    run_num_bits.to_string() +
+    name_bits.to_string());
 
-  std::bitset<bits32+bits32+bitsSizeT> combined_bits(event_num_bits.to_string() + run_num_bits.to_string() + name_bits.to_string());
-
-  return std::hash<std::bitset<bits32+bits32+bitsSizeT>>{}(combined_bits);
+  return std::hash<std::bitset<bits64+bits32+bits32+bitsSizeT>>{}(combined_bits);
 }
diff --git a/k4FWCore/components/UniqueIDGenSvc.h b/k4FWCore/components/UniqueIDGenSvc.h
@@ -7,11 +7,20 @@
 #include <GaudiKernel/Service.h>
 #include "k4Interface/IUniqueIDGenSvc.h"
 
+
+/** @class UniqueIDGenSvc
+ *  Generate unique, reproducible numbers using
+ *  event number, run number, algorithm name, and global seed.
+ *  To be used as reproducible per event seeds for random number generators used inside algorithms.
+ *
+ */
 class UniqueIDGenSvc : public extends<Service, IUniqueIDGenSvc> {
 public:
   UniqueIDGenSvc(const std::string& name, ISvcLocator* svcLoc);
   StatusCode initialize() override;
-  size_t getUniqueID(uint32_t evt_num, uint32_t run_num, std::string name) const override;
+  size_t getUniqueID(uint32_t evt_num, uint32_t run_num, const std::string& name) const override;
+private:
+  Gaudi::Property<int64_t> m_seed{this, "Seed", {123456789}};
 };
 
 #endif
diff --git a/k4Interface/include/k4Interface/IUniqueIDGenSvc.h b/k4Interface/include/k4Interface/IUniqueIDGenSvc.h
@@ -9,9 +9,17 @@
 
 #include <GaudiKernel/IInterface.h>
 
+/** @class IUniqueIDGenSvc
+ *
+ *  Interface to the UniqueIDGenSvc
+ *
+ *  @author Placido Fernandez Declara
+ */
+
 struct GAUDI_API IUniqueIDGenSvc : extend_interfaces<IInterface> {
   DeclareInterfaceID(IUniqueIDGenSvc, 2, 0);
-  virtual size_t getUniqueID(uint32_t evt_num, uint32_t run_num, std::string name) const = 0;
+  virtual size_t getUniqueID(
+    uint32_t evt_num, uint32_t run_num, const std::string& name) const = 0;
 };
 
 #endif
diff --git a/test/k4FWCoreTest/options/TestUniqueIDGenSvc.py b/test/k4FWCoreTest/options/TestUniqueIDGenSvc.py
@@ -1,5 +1,8 @@
 from Gaudi.Configuration import *
 
+from Configurables import UniqueIDGenSvc
+UniqueIDGenSvc().Seed = 987
+
 from Configurables import ApplicationMgr
 ApplicationMgr().EvtSel = "NONE"
 ApplicationMgr().EvtMax = 5

diff --git a/test/k4FWCoreTest/src/components/TestUniqueIDGenSvc.h b/test/k4FWCoreTest/src/components/TestUniqueIDGenSvc.h
@@ -2,8 +2,7 @@
 #define TEST_UNIQUEIDGENSVC_H
 
 // GAUDI
-#include "GaudiAlg/GaudiAlgorithm.h"
-
+#include <GaudiAlg/GaudiAlgorithm.h>
 
 #include "k4Interface/IUniqueIDGenSvc.h"