Index: /trunk/Mars/fact/processing/ontime.C
===================================================================
--- /trunk/Mars/fact/processing/ontime.C	(revision 15513)
+++ /trunk/Mars/fact/processing/ontime.C	(revision 15513)
@@ -0,0 +1,90 @@
+void ontime(const char *fname, double beg=0, double end=100000)
+{
+    //open the file
+    fits file(fname);
+
+    //file.PrintColumns();
+    //file.PrintKeys();
+
+    //allocate variables to read data into
+    Double_t time;
+    Float_t OnTime, ElTime, TriggerRate;
+    file.SetPtrAddress("Time",  &time);
+    file.SetPtrAddress("OnTime", &OnTime);
+    file.SetPtrAddress("ElapsedTime", &ElTime);
+    file.SetPtrAddress("TriggerRate", &TriggerRate);
+
+    //some file MJDREF offset fun. Before a given day, the MJDREF was not subtracted correctly.
+    //Also, see the logbook for more details (there are also some broken files)
+    UInt_t offset = file.GetUInt("MJDREF");
+    if (beg < 30000)
+        beg+=offset;
+    if (end < 30000)
+        end+=offset;
+
+    //variables to calculate stuff with
+    double  SumOnTime           = 0.;   //Sum up the OnTime_i for later effective on calculation
+    double  SumElTime           = 0.;   //sum up ElTime_i for later effective on calculation
+
+    double  SumOnEl             = 0.;   //Sum of the OnTime_i / ElapsedTime_i
+    double  SumOnEl2            = 0.;   //Sum of the (OnTime_i / ElapsedTime_i)^2,
+                                        //both values needed for variance of the effective on timeseries
+
+    double  EffectiveOn         = 0.;   //this will be the one effective on value
+    double  EffectiveOnRMS      = 0.;   //this will be variance(effective on)
+    int     counter             = 0;    //cnt the number of non zero ElTime datapoints
+
+    double  TriggerTimeOver125  = 0.;   //this will be the time  in sec the Trigger
+                                        //is above 125Hz
+
+    //loop over all rows in slow-file
+    while (file.GetNextRow())
+    {
+        //add the offset, as the data is saved with the offset subtracted
+        time += offset;
+
+        //if the end of the run is reached, break
+        if (time>end)
+            break;
+
+        //if the data is before the beginning of the run, continue
+        if (time<beg)
+        {
+            continue;
+        }
+
+        //sum the data for the mean effective on
+        SumOnTime   += OnTime;
+        SumElTime   += ElTime;
+
+        //sum the data for the variance of the effective on timeseries, check for zero elapsed time
+        if (ElTime>0){
+            SumOnEl     += OnTime/ElTime;
+            SumOnEl2    += OnTime/ElTime*OnTime/ElTime;
+            counter++;
+            //cout << "OnTime:" << OnTime << " # ElTime:" << ElTime << " # OnTime/ElTime:" << OnTime/ElTime << " # (OnTime/ElTime)^2:" << OnTime/ElTime*OnTime/ElTime << " # Counter:" << counter << endl;
+        }
+
+        //sum the time the trigger is over 125Hz
+        if (TriggerRate>125.){
+            TriggerTimeOver125 += ElTime;
+        }
+
+    }
+
+    //cout << "SumOnEl2:" << SumOnEl2 << " # SumOnEl:" << SumOnEl << " # (SumOnEl2/counter-(SumOnEl/counter*SumOnEl/counter)): " << (SumOnEl2/counter-(SumOnEl/counter*SumOnEl/counter)) << endl;
+
+    //calculate the return values, watch out for traps when doing math operations!
+    EffectiveOn         = SumElTime>0 ? SumOnTime/SumElTime : 0.;
+    EffectiveOnRMS      = counter>0 ? (SumOnEl2/counter-
+                                       (SumOnEl/counter*SumOnEl/counter)) : 0.;
+    EffectiveOnRMS      = EffectiveOnRMS>0 ? sqrt(EffectiveOnRMS) : 0;
+
+    //check for crap data, which happenes sometimes...
+    if (EffectiveOn>1.) EffectiveOn = 1.;
+    if (EffectiveOnRMS>0.5) EffectiveOnRMS = 0.5;
+
+    //return fun. The style from daniela (grep the output) requires an non scientific notation,
+    //i.e. withour exponential+ therefore set the precision to ~double with fixed width after decimal point
+    cout << setiosflags(ios::fixed) << setprecision(12) << "result " << EffectiveOn << " " << EffectiveOnRMS << " " << SumOnTime << " " << TriggerTimeOver125 << endl;
+}