Added option to RPMDIntegrator.getState() to specify force groups

plugins/rpmd/openmmapi/include/openmm/RPMDIntegrator.h

@@ -145,8 +145,10 @@ public:
      * @param enforcePeriodicBox if false, the position of each particle will be whatever position
      * is stored by the integrator, regardless of periodic boundary conditions.  If true, particle
      * positions will be translated so the center of every molecule lies in the same periodic box.
+     * @param groups a set of bit flags for which force groups to include when computing forces
+     * and energies.  Group i will be included if (groups&(1<<i)) != 0.  The default value includes all groups.
      */
-    State getState(int copy, int types, bool enforcePeriodicBox=false);
+    State getState(int copy, int types, bool enforcePeriodicBox=false, int groups=0xFFFFFFFF);
     /**
      * Advance a simulation through time by taking a series of time steps.
      *

plugins/rpmd/openmmapi/src/RPMDIntegrator.cpp

@@ -81,9 +81,9 @@ void RPMDIntegrator::setVelocities(int copy, const vector<Vec3>& velocities) {
     hasSetVelocity = true;
 }
 
-State RPMDIntegrator::getState(int copy, int types, bool enforcePeriodicBox) {
+State RPMDIntegrator::getState(int copy, int types, bool enforcePeriodicBox, int groups) {
     dynamic_cast<IntegrateRPMDStepKernel&>(kernel.getImpl()).copyToContext(copy, *context);
-    return context->getOwner().getState(types, enforcePeriodicBox);
+    return context->getOwner().getState(types, enforcePeriodicBox, groups);
 }
 
 void RPMDIntegrator::step(int steps) {