Changeset 3666 for trunk/MagicSoft/Mars/mbase/MMath.cc

Timestamp:

04/06/04 13:41:56 (20 years ago)

Author:

tbretz

Message:

*** empty log message ***

File:

• trunk/MagicSoft/Mars/mbase/MMath.cc (modified) (3 diffs)

trunk/MagicSoft/Mars/mbase/MMath.cc

@@ -52 +52 @@
 // --------------------------------------------------------------------------
 //
+// Symmetrized significance - this is somehow analog to
+// SignificanceLiMaSigned
+//
+// Returns Significance(s,b) if s>b otherwise -Significance(b, s);
+// 
+Double_t MMath::SignificanceSym(Double_t s, Double_t b)
+{
+    return s>b ? Significance(s, b) : -Significance(b, s);
+}
+
+// --------------------------------------------------------------------------
+//
 //  calculates the significance according to Li & Ma
 //  ApJ 272 (1983) 317, Formula 17
@@ -58 +70 @@
 //  b                    // b: number of off events
 //  alpha = t_on/t_off;  // t: observation time
+//
+//  The significance has the same (positive!) value for s>b and b>s.
 //
 //  Returns -1 if sum<0 or alpha<0 or the argument of sqrt<0
@@ -77 +91 @@
     return l+m<0 ? -1 : TMath::Sqrt((l+m)*2);
 }
+
+// --------------------------------------------------------------------------
+//
+// Calculates MMath::SignificanceLiMa(s, b, alpha). Returns 0 if the
+// calculation has failed. Otherwise the Li/Ma significance which was
+// calculated. If s<b a negative value is returned.
+//
+Double_t MMath::SignificanceLiMaSigned(Double_t s, Double_t b, Double_t alpha)
+{
+    const Double_t sig = SignificanceLiMa(s, b, alpha);
+    if (sig<=0)
+        return 0;
+
+    return TMath::Sign(sig, s-b);
+}