Add likelihood fit event selection hook (#3912)

Jürgen Knödlseder
1 parent 44df8963
Showing 4 changed files with 36 additions and 2 deletions
ChangeLog
NEWS
doc/source/admin/release_history/2.0.rst
src/obs/GObservation.cpp
@@ -3,6 +3,7 @@
         * Version 2.0.0 released
         ========================
  
+        Add likelihood fit event selection hook (#3912)
         Add GCOMModelDRM class (#3910)
         Add angle(GVector&,GVector&) friend function (#3908)
         Make extension name check case insensitive in GFits::extno()
@@ -248,6 +248,8 @@ of functions (#3328).
  
 11. Observation module
 ----------------------
+Add likelihood fit event selection hook (#3912).
+
 Add numerical gradient step size as member of GObservation to allow instrument-
 specific step size values.
  
@@ -36,6 +36,8 @@ Bug fixes
 Improvements
 ------------
  
+* [`3912 <https://cta-redmine.irap.omp.eu/issues/3912>`_] -
+  Add likelihood fit event selection hook
 * [`3908 <https://cta-redmine.irap.omp.eu/issues/3908>`_] -
   Add ``angle(GVector&,GVector&)`` friend function
 * Make extension name check case insensitive in ``GFits::extno()``
@@ -1399,8 +1399,10 @@ double GObservation::likelihood_poisson_unbinned(const GModels&amp; models,
     // Iterate over all events
     for (int i = 0; i < nevents; ++i) {
  
-        // Get event pointer
-        const GEvent* event = (*events())[i];
+        // Skip events that should not be used
+        if (!use_event_for_likelihood(i)) {
+            continue;
+        }
  
         // Get model value
         double model = model_vector[i];
@@ -1533,6 +1535,11 @@ double GObservation::likelihood_poisson_binned(const GModels&amp; models,
     // Iterate over all bins
     for (int i = 0; i < nevents; ++i) {
  
+        // Skip events that should not be used
+        if (!use_event_for_likelihood(i)) {
+            continue;
+        }
+
         // Update number of bins
         #if defined(G_OPT_DEBUG)
         n_bins++;
@@ -1735,6 +1742,11 @@ double GObservation::likelihood_gaussian_binned(const GModels&amp; models,
     // Iterate over all bins
     for (int i = 0; i < nevents; ++i) {
  
+        // Skip events that should not be used
+        if (!use_event_for_likelihood(i)) {
+            continue;
+        }
+
         // Get event pointer
         const GEventBin* bin =
             (*(static_cast<GEventCube*>(const_cast<GEvents*>(events()))))[i];
@@ -1824,6 +1836,23 @@ double GObservation::likelihood_gaussian_binned(const GModels&amp; models,
 }
  
  
+/***********************************************************************//**
+ * @brief Check whether bin should be used for likelihood analysis
+ *
+ * @param[in] index Event index.
+ * @return True.
+ *
+ * This is a dummy virtual method that allows implementation of a hook for
+ * event selection in the likelihood computation. The dummy method always
+ * returns true.
+ ***************************************************************************/
+bool GObservation::use_event_for_likelihood(const int& index) const
+{
+    // Return true
+    return true;
+}
+
+
 /*==========================================================================
  =                                                                         =
  =                         Model gradient methods                          =