Merge pull request #1517 from peastman/drude

DrudeLangevinIntegrator was not disabling hardwall constraint for maxDistance=0

plugins/drude/platforms/cuda/src/CudaDrudeKernels.cpp

@@ -364,9 +364,11 @@ void CudaIntegrateDrudeLangevinStepKernel::execute(ContextImpl& context, const D
     
     // Apply hard wall constraints.
     
+    if (maxDrudeDistance > 0) {
         void* hardwallArgs[] = {&cu.getPosq().getDevicePointer(), &posCorrection, &cu.getVelm().getDevicePointer(),
                 &pairParticles->getDevicePointer(), &integration.getStepSize().getDevicePointer(), maxDrudeDistancePtr, hardwallscaleDrudePtr};
         cu.executeKernel(hardwallKernel, hardwallArgs, pairParticles->getSize());
+    }
     integration.computeVirtualSites();
 
     // Update the time and step count.

plugins/drude/platforms/opencl/src/OpenCLDrudeKernels.cpp

@@ -376,6 +376,7 @@ void OpenCLIntegrateDrudeLangevinStepKernel::execute(ContextImpl& context, const
     
     // Apply hard wall constraints.
     
+    if (maxDrudeDistance > 0)
         cl.executeKernel(hardwallKernel, pairParticles->getSize());
     integration.computeVirtualSites();