Document how to make internal plots of truncation in Tracklet code. (c…

…ms-sw#256)

* Document writeMonitorData cfg

* Update README.md

L1Trigger/TrackFindingTracklet/README.md

@@ -15,3 +15,8 @@ Both can be run via makeHists.csh .
 
 The optional "NewKF" track fit can be run by changing L1TRKALGO=HYBRID_NEWKF. It corresponds to the curent FW, but is is not yet the default, as only a basic duplicate track removal is available for it. It is configured via 
 TrackTrigger/python/ProducerSetup_cfi.py, (which also configures the DTC).
+
+For experts
+============
+
+1) To make plots to monitor data rates assicuated to truncation after each step in the tracklet pattern reco algo, set writeMonitorData_ = true in Settings.h . This creates txt files, which the ROOT macros in https://github.com/cms-L1TK/TrackPerf/tree/master/PatternReco can then use to study truncation of individual algo steps within tracklet chain.

L1Trigger/TrackFindingTracklet/interface/Settings.h

@@ -893,7 +893,9 @@ namespace trklet {
         {"TRE", 108},
         {"DR", 108}};  //Specifies how many tracks allowed per bin in DR
 
-    // If set to true this will generate debub printout in text files
+    // If set to true this creates txt files, which the ROOT macros in 
+    // https://github.com/cms-L1TK/TrackPerf/tree/master/PatternReco
+    // can then use to study truncation of individual algo steps within tracklet chain.
     std::unordered_map<std::string, bool> writeMonitorData_{{"IL", false},
                                                             {"TE", false},
                                                             {"CT", false},