[Rivet-svn] rivet: 2 new changesets

[Rivet Mercurial]

details:   https://rivet.hepforge.org/hg/rivet/rev/5819ee47434f
branches:  
changeset: 5256:5819ee47434f
user:      Andy Buckley <andy at insectnation.org>
date:      Tue Jun 14 12:51:24 2016 +0100
description:
Add and rename 4-vector boost calculation methods: new methods beta, betaVec, gamma & gammaVec are now preferred to the deprecated boostVector method.

details:   https://rivet.hepforge.org/hg/rivet/rev/7814ff1af043
branches:  
changeset: 5257:7814ff1af043
user:      Andy Buckley <andy at insectnation.org>
date:      Tue Jun 14 12:54:37 2016 +0100
description:
Use betaVec rather than boostVector

diffs (truncated from 337 to 50 lines):

--- a/ChangeLog	Mon Jun 13 21:29:26 2016 +0100
+++ b/ChangeLog	Tue Jun 14 12:54:37 2016 +0100
@@ -1,3 +1,9 @@
+2016-06-14  Andy Buckley  <andy.buckley at cern.ch>
+
+	* Add and rename 4-vector boost calculation methods: new methods
+	beta, betaVec, gamma & gammaVec are now preferred to the
+	deprecated boostVector method.
+
 2016-06-13  Andy Buckley  <andy.buckley at cern.ch>
 
 	* Add and use projection handling methods declare(proj, pname) and
--- a/include/Rivet/Math/Vector4.hh	Mon Jun 13 21:29:26 2016 +0100
+++ b/include/Rivet/Math/Vector4.hh	Tue Jun 14 12:54:37 2016 +0100
@@ -614,23 +614,41 @@
       return E() * sin(polarAngle());
     }
 
+    //@}
 
-    /// Calculate the boost vector (in units of \f$ \beta \f$).
-    Vector3 boostVector() const {
-      // const Vector3 p3 = vector3();
-      // const double m2 = mass2();
-      // if (Rivet::isZero(m2)) return p3.unit();
-      // else {
-      //   // Could also do this via beta = tanh(rapidity), but that's
-      //   // probably more messy from a numerical hygiene point of view.
-      //   const double p2 = p3.mod2();
-      //   const double beta = sqrt( p2 / (m2 + p2) );
-      //   return beta * p3.unit();
-      // }
-      /// @todo Be careful about c=1 convention...
-      return Vector3(px()/E(), py()/E(), pz()/E());
+
+    /// @name Lorentz boost factors and vectors
+    //@{
+
+    /// Calculate the boost factor \f$ \gamma \f$.
+    /// @note \f$ \gamma = E/mc^2 \f$ so we rely on the c=1 convention
+    double gamma() const {
+      return sqrt(E2()/mass2());
     }
 
+    /// Calculate the boost vector \f$ \vec{\gamma} \f$.
+    /// @note \f$ \gamma = E/mc^2 \f$ so we rely on the c=1 convention
+    Vector3 gammaVec() const {
+      return gamma() * p3().unit();
+    }
+