- Changes to saving of IterationConfigs to several files:

  - Add option of using %s in file-name-format that injects algorithm name.
  - Make writing of iteration-info index in JSON save files optional.
    Default now is not to write.
    This is to be used when loading a single IterationConfig.
```
void ConfigJson_Save_Iterations(IterationsInfo &its_info, const std::string &fname_fmt,
                                bool include_iter_info_preamble);
```

- Provide another version of JSON reading where a single iteration is loaded
  over an existing one. These are the two variants:
```
// Patch IterationsInfo from a vector of files.
// Assumes patch files include iteration-info preambles, i.e., they
// were saved with include_iter_info_preamble=true.
// If report is non-null counts are added to existing object.
void             ConfigJson_Patch_Files(IterationsInfo &its_info, const std::vector<std::string> &fnames,
                                       ConfigJsonPatcher::PatchReport *report=nullptr);

// Load a single iteration from JSON file.
// Searches for a match between m_algorithm in its_info and in JSON file to decide
// which IterationConfig it will load over.
// Assumes JSON file has been saved WITHOUT iteration-info preamble.
// Returns reference to the selected IterationConfig.
// If report is non-null counts are added to existing object.
IterationConfig& ConfigJson_Load_File(IterationsInfo &its_info, const std::string &fname,
                                      ConfigJsonPatcher::PatchReport *report=nullptr);
```

- Add new command-line options and remove 'patch' from most of the existing one:
```
JSON config patcher options:

  --json-load  <filename>  load iteration config from given JSON file (def: do not load)
                           can be specified multiple times for several files
  --json-patch <filename>  patch iteration config from given JSON file (def: do not patch)
                           can be specified multiple times for several files
  --json-save-iterations <fname-fmt> save per iteration json files
                           %d in fname-fmt gets replaced with iteration number
                           %s in fname-fmt get replaced with iteration algorithm name
                           exactly one of %d and %s must be specified
  --json-save-iterations-include-iter-info-preamble (def: false)
  --json-verbose     print each patch assignment as it is being made (def: false)
  --json-dump-before print iteration config before patching (def: false)
  --json-dump-after  print iteration config after  patching (def: false)
```

- When counting replacements of leaf config values only count assignments where value
  has actually changed.

- Use nlohmann::ordered_json when saving configs to JSON files and dumping to stdout.
  This preserves data-member definition order and makes these outputs more readable.

Config.cc

@@ -99,11 +99,13 @@ namespace Config
   bool  backwardFit = false;
   bool  includePCA = false;
 
-  bool        json_patch_dump_before = false;
-  bool        json_patch_dump_after  = false;
-  bool        json_patch_verbose     = false;
+  bool        json_dump_before = false;
+  bool        json_dump_after  = false;
+  bool        json_verbose     = false;
   std::vector<std::string> json_patch_filenames;
+  std::vector<std::string> json_load_filenames;
   std::string              json_save_iters_fname_fmt;
+  bool        json_save_iters_include_iter_info_preamble = false;
 
   void RecalculateDependentConstants()
   {

Config.h

@@ -399,11 +399,13 @@ namespace Config
 
   // ================================================================
 
-  extern bool        json_patch_dump_before;
-  extern bool        json_patch_dump_after;
-  extern bool        json_patch_verbose;
+  extern bool        json_dump_before;
+  extern bool        json_dump_after;
+  extern bool        json_verbose;
   extern std::vector<std::string> json_patch_filenames;
+  extern std::vector<std::string> json_load_filenames;
   extern std::string              json_save_iters_fname_fmt;
+  extern bool        json_save_iters_include_iter_info_preamble;
 
   // ================================================================
 

Track.cc

@@ -100,6 +100,25 @@ bool TrackBase::hasSillyValues(bool dump, bool fix, const char* pref)
   return is_silly;
 }
 
+const char* TrackBase::algoint_to_cstr(int algo)
+{
+  static const char* names[] = { "undefAlgorithm", "ctf", "duplicateMerge",
+    "cosmics", "initialStep", "lowPtTripletStep", "pixelPairStep", "detachedTripletStep",
+    "mixedTripletStep", "pixelLessStep", "tobTecStep", "jetCoreRegionalStep", "conversionStep",
+    "muonSeededStepInOut", "muonSeededStepOutIn", "outInEcalSeededConv", "inOutEcalSeededConv",
+    "nuclInter", "standAloneMuon", "globalMuon", "cosmicStandAloneMuon", "cosmicGlobalMuon",
+    "highPtTripletStep", "lowPtQuadStep", "detachedQuadStep", "reservedForUpgrades1",
+    "reservedForUpgrades2", "bTagGhostTracks", "beamhalo", "gsf", "hltPixel", "hltIter0",
+    "hltIter1", "hltIter2", "hltIter3", "hltIter4", "hltIterX", "hiRegitMuInitialStep",
+    "hiRegitMuLowPtTripletStep", "hiRegitMuPixelPairStep", "hiRegitMuDetachedTripletStep",
+    "hiRegitMuMixedTripletStep", "hiRegitMuPixelLessStep", "hiRegitMuTobTecStep",
+    "hiRegitMuMuonSeededStepInOut", "hiRegitMuMuonSeededStepOutIn", "algoSize" };
+
+    if (algo < 0 || algo >= (int) TrackAlgorithm::algoSize) return names[0];
+    return names[algo];
+}
+
+
 //==============================================================================
 // Track
 //==============================================================================

Track.h

@@ -341,6 +341,8 @@ class TrackBase
   // bool isStopped() const { return status_.stopped; }
   // void setStopped()      { status_.stopped = true; }
 
+  static const char* algoint_to_cstr(int algo);
+
   // ------------------------------------------------------------------------
 
 protected:

mkFit/IterationConfig.cc

@@ -1,5 +1,6 @@
 #include "IterationConfig.h"
 #include "Config.h"
+#include "Track.h" // for TrackBase::algoint_to_cstr, sigh
 
 #include "nlohmann/json.hpp"
 
@@ -8,11 +9,18 @@
 #include <iostream>
 #include <iomanip>
 
+// Redefine to also support ordered_json ... we want to keep variable order in JSON save files.
+#define ITCONF_DEFINE_TYPE_NON_INTRUSIVE(Type, ...)  \
+    inline void to_json(nlohmann::json& nlohmann_json_j, const Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_TO, __VA_ARGS__)) } \
+    inline void from_json(const nlohmann::json& nlohmann_json_j, Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_FROM, __VA_ARGS__)) } \
+    inline void to_json(nlohmann::ordered_json& nlohmann_json_j, const Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_TO, __VA_ARGS__)) } \
+    inline void from_json(const nlohmann::ordered_json& nlohmann_json_j, Type& nlohmann_json_t) { NLOHMANN_JSON_EXPAND(NLOHMANN_JSON_PASTE(NLOHMANN_JSON_FROM, __VA_ARGS__)) }
+
 namespace mkfit {
 
 // Begin AUTO code, some members commented out.
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationLayerConfig,
+ITCONF_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationLayerConfig,
   /* float */   m_select_min_dphi,
   /* float */   m_select_max_dphi,
   /* float */   m_select_min_dq,
@@ -31,7 +39,7 @@ NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationLayerConfig,
   /* float */   c_c2_2
 )
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationParams,
+ITCONF_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationParams,
   /* int */   nlayers_per_seed,
   /* int */   maxCandsPerSeed,
   /* int */   maxHolesPerCand,
@@ -50,7 +58,7 @@ NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationParams,
   /* float */   c_dzmax_el
 )
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationConfig,
+ITCONF_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationConfig,
   // /* int */   m_iteration_index,
   /* int */                      m_track_algorithm,
   /* mkfit::IterationParams */   m_params,
@@ -63,7 +71,7 @@ NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationConfig,
   // /* function<void(const TrackerInfo&,const TrackVec&,const EventOfHits&,IterationSeedPartition&)> */   m_partition_seeds
 )
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationsInfo,
+ITCONF_DEFINE_TYPE_NON_INTRUSIVE(mkfit::IterationsInfo,
   /* vector<mkfit::IterationConfig> */   m_iterations
 )
 
@@ -243,12 +251,18 @@ int ConfigJsonPatcher::replace(const nlohmann::json &j)
                 std::string s("/");
                 s += key;
                 nlohmann::json::json_pointer jp(s);
-                if (m_verbose)
+                if (m_current->at(jp) != value)
                 {
-                    std::cout << "  " << get_abs_path() << s << ": " << m_current->at(jp) << " -> " << value << "\n";
+                    if (m_verbose)
+                        std::cout << "  " << get_abs_path() << s << ": " << m_current->at(jp) << " -> " << value << "\n";
+
+                    m_current->at(jp) = value;
+                    ++n_replaced;
                 }
-                m_current->at(jp) = value;
-                ++n_replaced;
+                // else {
+                //     if (m_verbose)
+                //         std::cout << "  " << get_abs_path() << s << ": " << m_current->at(jp) << " -> unchanged\n";
+                // }
             }
             else
             {
@@ -382,113 +396,179 @@ namespace
     }
 }
 
-ConfigJsonPatcher::PatchReport
-ConfigJson_Patch_File(IterationsInfo &its_info, const std::vector<std::string> &fnames)
+void ConfigJson_Patch_Files(IterationsInfo &its_info, const std::vector<std::string> &fnames,
+                           ConfigJsonPatcher::PatchReport *report)
 {
-    using nlohmann::json;
-
-    ConfigJsonPatcher cjp(Config::json_patch_verbose);
+    ConfigJsonPatcher cjp(Config::json_verbose);
     cjp.Load(its_info);
 
-    if (Config::json_patch_dump_before)
-    {
-        std::cout << cjp.dump(3) << "\n";
-    }
-
-    ConfigJsonPatcher::PatchReport report;
+    ConfigJsonPatcher::PatchReport rep;
 
     for (auto &fname : fnames)
     {
         std::ifstream ifs;
         open_ifstream(ifs, fname, __func__);
 
-        if (Config::json_patch_verbose)
+        if (Config::json_verbose)
         {
             printf("%s begin reading from file %s.\n", __func__, fname.c_str());
         }
 
         int n_read = 0, n_tot_replaced = 0;
         while (skipws_ifstream(ifs))
         {
-            json j;
+            nlohmann::json j;
             ifs >> j;
             ++n_read;
 
-            if (Config::json_patch_verbose)
+            if (Config::json_verbose)
             {
                 std::cout << " Read JSON entity " << n_read << " -- applying patch:\n";
                 // std::cout << j.dump(3) << "\n";
             }
 
             int n_replaced = cjp.replace(j);
 
-            if (Config::json_patch_verbose)
+            if (Config::json_verbose)
             {
                 std::cout << " Replaced " << n_replaced << " entries.\n";
             }
             cjp.cd_top();
             n_tot_replaced += n_replaced;
         }
 
-        if (Config::json_patch_verbose)
+        if (Config::json_verbose)
         {
             printf("%s read %d JSON entities from file %s, replaced %d parameters.\n",
                 __func__, n_read, fname.c_str(), n_tot_replaced);
         }
 
         ifs.close();
 
-        report.inc_counts(1, n_read, n_tot_replaced);
+        rep.inc_counts(1, n_read, n_tot_replaced);
     }
 
-    if (Config::json_patch_dump_after)
+    if (rep.n_replacements > 0)
     {
-        std::cout << cjp.dump(3) << "\n";
+        cjp.Save(its_info);
     }
 
-    if (report.n_replacements > 0)
+    if (report) report->inc_counts(rep);
+}
+
+IterationConfig& ConfigJson_Load_File(IterationsInfo &its_info, const std::string &fname,
+                                      ConfigJsonPatcher::PatchReport *report)
+{
+    ConfigJsonPatcher::PatchReport rep;
+
+    std::ifstream ifs;
+    open_ifstream(ifs, fname, __func__);
+
+    if (Config::json_verbose)
     {
-        cjp.Save(its_info);
+        printf("%s begin reading from file %s.\n", __func__, fname.c_str());
     }
 
-    return report;
-}
+    if ( ! skipws_ifstream(ifs)) throw std::runtime_error("empty file");
+
+    nlohmann::json j;
+    ifs >> j;
+    int track_algo = j["m_track_algorithm"];
+
+    int iii = -1;
+    for (int i = 0; i < its_info.size(); ++i)
+    {
+        if (its_info[i].m_track_algorithm == track_algo) {
+            iii = i;
+            break;
+        }
+    }
+    if (iii == -1) throw std::runtime_error("matching IterationConfig not found");
+
+    if (Config::json_verbose)
+    {
+        std::cout << " Read JSON entity, Iteration index is " << iii << " -- applying patch:\n";
+    }
 
+    ConfigJsonPatcher cjp(Config::json_verbose);
+    cjp.Load(its_info[iii]);
+
+    int n_replaced = cjp.replace(j);
+
+    cjp.cd_top();
+
+    if (Config::json_verbose)
+    {
+        printf("%s read 1 JSON entity from file %s, replaced %d parameters.\n",
+            __func__, fname.c_str(), n_replaced);
+    }
+
+    ifs.close();
+
+    rep.inc_counts(1, 1, n_replaced);
+
+    if (rep.n_replacements > 0)
+    {
+        cjp.Save(its_info[iii]);
+    }
+
+    if (report) report->inc_counts(rep);
+
+    return its_info[iii];
+}
 
 // ============================================================================
 // Save each IterationConfig into a separate json file
 // ============================================================================
 
-void ConfigJson_Save_Iterations(IterationsInfo &its_info, const std::string &fname_fmt)
+void ConfigJson_Save_Iterations(IterationsInfo &its_info, const std::string &fname_fmt,
+                                bool include_iter_info_preamble)
 {
-    assert(fname_fmt.find("%d") != std::string::npos && "JSON save filename-format must include a %d substring");
+    bool has_pct_d = fname_fmt.find("%d") != std::string::npos;
+    bool has_pct_s = fname_fmt.find("%s") != std::string::npos;
+
+    assert( (has_pct_d || has_pct_s) && "JSON save filename-format must include a %d or %s substring");
+    assert(!(has_pct_d && has_pct_s) && "JSON save filename-format must include only one of %d or %s substrings");
 
     for (int ii = 0; ii < its_info.size(); ++ii)
     {
         const IterationConfig &itconf = its_info[ii];
 
         char fname[1024];
-        snprintf(fname, 1024, fname_fmt.c_str(), ii);
+        if (has_pct_d)
+            snprintf(fname, 1024, fname_fmt.c_str(), ii);
+        else
+            snprintf(fname, 1024, fname_fmt.c_str(), TrackBase::algoint_to_cstr(itconf.m_track_algorithm));
 
         std::ofstream ofs;
         open_ofstream(ofs, fname, __func__);
 
-        ofs << "{ \"m_iterations/" << ii << "\": ";
-
-        ofs << std::setprecision(5);
+        if (include_iter_info_preamble)
+        {
+            ofs << "{ \"m_iterations/" << ii << "\": ";
+        }
 
-        nlohmann::json j;
+        nlohmann::ordered_json j;
         to_json(j, itconf);
 
         ofs << std::setw(1);
         ofs << j;
 
-        ofs << " }\n";
+        if (include_iter_info_preamble)
+        {
+            ofs << " }";
+        }
 
+        ofs << "\n";
         ofs.close();
     }
 }
 
+void ConfigJson_Dump(IterationsInfo &its_info)
+{
+    nlohmann::ordered_json j = its_info;
+    std::cout << j.dump(3) << "\n";
+}
 
 // ============================================================================
 // Tests for ConfigJson stuff