Changeset 973b92a in git for external/fastjet/contribs/Nsubjettiness/ExtraRecombiners.cc

Timestamp:

Oct 9, 2015, 2:47:38 PM (9 years ago)

Author:

Pavel Demin <pavel.demin@…>

Branches:

ImprovedOutputFile, Timing, dual_readout, llp, master

Children:

8713dee

Parents:

f118021

Message:

update FastJet library to 3.1.3 and Nsubjettiness library to 2.2.1

File:

• external/fastjet/contribs/Nsubjettiness/ExtraRecombiners.cc (moved) (moved from external/fastjet/contribs/Nsubjettiness/WinnerTakeAllRecombiner.cc ) (2 diffs)

external/fastjet/contribs/Nsubjettiness/ExtraRecombiners.cc

@@ -5 +5 @@
 //  Jesse Thaler, Ken Van Tilburg, Christopher K. Vermilion, and TJ Wilkason
 //
-//  $Id: WinnerTakeAllRecombiner.cc 597 2014-04-16 23:07:55Z jthaler $
+//  $Id: ExtraRecombiners.cc 842 2015-08-20 13:44:31Z jthaler $
 //----------------------------------------------------------------------
 // This file is part of FastJet contrib.
@@ -23 +23 @@
 //----------------------------------------------------------------------
 
-#include "WinnerTakeAllRecombiner.hh"
+#include "ExtraRecombiners.hh"
 
 FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh
 
 namespace contrib{
+  
+std::string GeneralEtSchemeRecombiner::description() const {
+   return "General Et-scheme recombination";
+}
+
+// recombine pa and pb according to a generalized Et-scheme parameterized by the power delta
+void GeneralEtSchemeRecombiner::recombine(const fastjet::PseudoJet & pa, const fastjet::PseudoJet & pb, fastjet::PseudoJet & pab) const {
+   
+   // Define new weights for recombination according to delta
+   // definition of ratio done so that we do not encounter issues about numbers being too large for huge values of delta
+   double ratio;
+   if (std::abs(_delta - 1.0) < std::numeric_limits<double>::epsilon()) ratio = pb.perp()/pa.perp(); // save computation time of pow()
+   else ratio = pow(pb.perp()/pa.perp(), _delta);
+   double weighta = 1.0/(1.0 + ratio);
+   double weightb = 1.0/(1.0 + 1.0/ratio);
+   
+   double perp_ab = pa.perp() + pb.perp();
+   // reweight the phi and rap sums according to the weights above
+   if (perp_ab != 0.0) {
+      double y_ab = (weighta * pa.rap() + weightb * pb.rap());
+      
+      double phi_a = pa.phi(), phi_b = pb.phi();
+      if (phi_a - phi_b > pi)  phi_b += twopi;
+      if (phi_a - phi_b < -pi) phi_b -= twopi;
+      double phi_ab = (weighta * phi_a + weightb * phi_b);
+      
+      pab.reset_PtYPhiM(perp_ab, y_ab, phi_ab);
+      
+   }
+   else {
+      pab.reset(0.0,0.0,0.0,0.0);
+   }
+}
+
 
 std::string WinnerTakeAllRecombiner::description() const {
-   return "Winner Take All scheme recombination";
+   return "Winner-Take-All recombination";
 }