Added SigmaPerVdwRadius and VdwRadiusPerSigma and removed bootleg declarations from examples.

examples/HelloEthane.cpp

@@ -208,14 +208,6 @@ int main() {
 #include "OpenMM.h"
 using OpenMM::Vec3; // so we can just say "Vec3" below
 
-// Add definitions missing from the current version of OpenMM.
-namespace OpenMM {
-// This conversion factor takes you from a van der Waals radius (defined as 1/2 
-// the minimum energy separation) to the related Lennard Jones "sigma" parameter
-// (defined as the zero crossing separation). The value is 2*pow(2, -1/6).
-static const double SigmaPerVdwRadius = 1.78179743628068;
-}
-
 // This is our opaque "handle" class containing all the OpenMM objects that
 // must persist from call to call during a simulation. The main program gets 
 // a pointer to one of these but sees it as essentially a void* since it 

examples/HelloSodiumChloride.cpp

@@ -166,14 +166,6 @@ int main() {
 #include "OpenMM.h"
 using OpenMM::Vec3; // so we can just say "Vec3" below
 
-// Add definition missing from the current version of OpenMM.
-namespace OpenMM {
-// This conversion factor takes you from a van der Waals radius (defined as 1/2 
-// the minimum energy separation) to the related Lennard Jones "sigma" parameter
-// (defined as the zero crossing separation). The value is 2*pow(2, -1/6).
-static const double SigmaPerVdwRadius = 1.78179743628068;
-}
-
 struct MyOpenMMData {
     MyOpenMMData() : system(0), context(0), integrator(0) {}
     ~MyOpenMMData() {delete system; delete context; delete integrator;}

examples/HelloWaterBox.cpp

@@ -176,13 +176,6 @@ int main() {
 #include "OpenMM.h"
 using OpenMM::Vec3; // so we can just say "Vec3" below
 
-// Add definition missing from the current version of OpenMM.
-namespace OpenMM {
-// This conversion factor takes you from a van der Waals radius (defined as 1/2 
-// the minimum energy separation) to the related Lennard Jones "sigma" parameter
-// (defined as the zero crossing separation). The value is 2*pow(2, -1/6).
-static const double SigmaPerVdwRadius = 1.78179743628068;
-}
 
 // This is our opaque "handle" class containing all the OpenMM objects that
 // must persist from call to call during a simulation. The main program gets 

examples/OpenMM_CWrapper.h

@@ -126,7 +126,7 @@ static const double OpenMM_DegreesPerRadian = 180.0/3.1415926535897932385;
  * "sigma" parameter (defined as the zero crossing separation). The value
  * is 2*pow(2, -1/6).
  */
-static const double OpenMM_SigmaPerVdwRadius = 1.78179743628068;
+static const double OpenMM_SigmaPerVdwRadius = 1.7817974362806786095;
 
 
 #if defined(__cplusplus)

openmmapi/include/openmm/Units.h

@@ -83,6 +83,14 @@ namespace OpenMM {
      * The number of degrees in a radian.
      */
     static const double DegreesPerRadian = 180.0/3.1415926535897932385;
+    /**
+     * L-J sigma per unit van der Waals radius: 2/(2^1/6).
+     */
+    static const double SigmaPerVdwRadius = 1.7817974362806786095;
+    /**
+     * van der Waals radius per unit L-J sigma: (2^1/6)/2.
+     */
+    static const double VdwRadiusPerSigma = .56123102415468649070;
 
 } // namespace OpenMM