Throw an exception if the cutoff distance is greater than half the box size (bug 1023)

openmmapi/src/CustomGBForceImpl.cpp

@@ -95,6 +95,13 @@ void CustomGBForceImpl::initialize(ContextImpl& context) {
         exclusions[particle1].insert(particle2);
         exclusions[particle2].insert(particle1);
     }
+    if (owner.getNonbondedMethod() == CustomGBForce::CutoffPeriodic) {
+        Vec3 boxVectors[3];
+        system.getPeriodicBoxVectors(boxVectors[0], boxVectors[1], boxVectors[2]);
+        double cutoff = owner.getCutoffDistance();
+        if (cutoff > 0.5*boxVectors[0][0] || cutoff > 0.5*boxVectors[1][1] || cutoff > 0.5*boxVectors[2][2])
+            throw OpenMMException("CustomGBForce: The cutoff distance cannot be greater than half the periodic box size.");
+    }
     dynamic_cast<CalcCustomGBForceKernel&>(kernel.getImpl()).initialize(context.getSystem(), owner);
 }
 

openmmapi/src/CustomNonbondedForceImpl.cpp

@@ -95,6 +95,13 @@ void CustomNonbondedForceImpl::initialize(ContextImpl& context) {
         exclusions[particle1].insert(particle2);
         exclusions[particle2].insert(particle1);
     }
+    if (owner.getNonbondedMethod() == CustomNonbondedForce::CutoffPeriodic) {
+        Vec3 boxVectors[3];
+        system.getPeriodicBoxVectors(boxVectors[0], boxVectors[1], boxVectors[2]);
+        double cutoff = owner.getCutoffDistance();
+        if (cutoff > 0.5*boxVectors[0][0] || cutoff > 0.5*boxVectors[1][1] || cutoff > 0.5*boxVectors[2][2])
+            throw OpenMMException("CustomNonbondedForce: The cutoff distance cannot be greater than half the periodic box size.");
+    }
     dynamic_cast<CalcCustomNonbondedForceKernel&>(kernel.getImpl()).initialize(context.getSystem(), owner);
 }
 

openmmapi/src/GBSAOBCForceImpl.cpp

@@ -45,6 +45,13 @@ void GBSAOBCForceImpl::initialize(ContextImpl& context) {
     kernel = context.getPlatform().createKernel(CalcGBSAOBCForceKernel::Name(), context);
     if (owner.getNumParticles() != context.getSystem().getNumParticles())
         throw OpenMMException("GBSAOBCForce must have exactly as many particles as the System it belongs to.");
+    if (owner.getNonbondedMethod() == GBSAOBCForce::CutoffPeriodic) {
+        Vec3 boxVectors[3];
+        context.getSystem().getPeriodicBoxVectors(boxVectors[0], boxVectors[1], boxVectors[2]);
+        double cutoff = owner.getCutoffDistance();
+        if (cutoff > 0.5*boxVectors[0][0] || cutoff > 0.5*boxVectors[1][1] || cutoff > 0.5*boxVectors[2][2])
+            throw OpenMMException("GBSAOBCForce: The cutoff distance cannot be greater than half the periodic box size.");
+    }
     dynamic_cast<CalcGBSAOBCForceKernel&>(kernel.getImpl()).initialize(context.getSystem(), owner);
 }
 

openmmapi/src/GBVIForceImpl.cpp

@@ -94,6 +94,13 @@ void GBVIForceImpl::initialize(ContextImpl& context) {
         bondIndices[i].push_back( particle2 );
         bondLengths[i] = bondLength;
     }   
+    if (owner.getNonbondedMethod() == GBVIForce::CutoffPeriodic) {
+        Vec3 boxVectors[3];
+        system.getPeriodicBoxVectors(boxVectors[0], boxVectors[1], boxVectors[2]);
+        double cutoff = owner.getCutoffDistance();
+        if (cutoff > 0.5*boxVectors[0][0] || cutoff > 0.5*boxVectors[1][1] || cutoff > 0.5*boxVectors[2][2])
+            throw OpenMMException("GBVIForce: The cutoff distance cannot be greater than half the periodic box size.");
+    }
 
     vector<double> scaledRadii;
     scaledRadii.resize(numberOfParticles);

openmmapi/src/NonbondedForceImpl.cpp

@@ -85,6 +85,15 @@ void NonbondedForceImpl::initialize(ContextImpl& context) {
         exceptions[particle1].insert(particle2);
         exceptions[particle2].insert(particle1);
     }
+    if (owner.getNonbondedMethod() == NonbondedForce::CutoffPeriodic ||
+            owner.getNonbondedMethod() == NonbondedForce::Ewald ||
+            owner.getNonbondedMethod() == NonbondedForce::PME) {
+        Vec3 boxVectors[3];
+        system.getPeriodicBoxVectors(boxVectors[0], boxVectors[1], boxVectors[2]);
+        double cutoff = owner.getCutoffDistance();
+        if (cutoff > 0.5*boxVectors[0][0] || cutoff > 0.5*boxVectors[1][1] || cutoff > 0.5*boxVectors[2][2])
+            throw OpenMMException("NonbondedForce: The cutoff distance cannot be greater than half the periodic box size.");
+    }
     dynamic_cast<CalcNonbondedForceKernel&>(kernel.getImpl()).initialize(context.getSystem(), owner);
 }