Loading a checkpoint marks that positions have been set

openmmapi/src/ContextImpl.cpp

@@ -449,4 +449,5 @@ void ContextImpl::loadCheckpoint(istream& stream) {
         parameters[name] = value;
     }
     updateStateDataKernel.getAs<UpdateStateDataKernel>().loadCheckpoint(*this, stream);
+    hasSetPositions = true;
 }

platforms/cpu/tests/TestCpuCheckpoints.cpp

@@ -92,6 +92,15 @@ void testCheckpoint() {
     integrator.step(10);
     State s4 = context.getState(State::Positions | State::Velocities | State::Parameters);
     compareStates(s2, s4);
+    
+    // See if a checkpoint created from one Context can be loaded into a different one.
+    
+    VerletIntegrator integrator2(0.001);
+    Context context2(system, integrator2, platform);
+    stream1.seekg(0, stream1.beg);
+    context2.loadCheckpoint(stream1);
+    State s5 = context2.getState(State::Positions | State::Velocities | State::Parameters | State::Energy);
+    compareStates(s1, s5);
 }
 
 void runPlatformTests() {

platforms/cuda/tests/TestCudaCheckpoints.cpp

@@ -120,6 +120,15 @@ void testCheckpoint() {
     integrator2.step(10);
     State s8 = context2.getState(State::Positions | State::Velocities | State::Parameters);
     compareStates(s6, s8);
+    
+    // See if a checkpoint created from one Context can be loaded into a different one.
+    
+    VerletIntegrator integrator3(0.001);
+    Context context3(system, integrator3, platform);
+    stream1.seekg(0, stream1.beg);
+    context3.loadCheckpoint(stream1);
+    State s9 = context3.getState(State::Positions | State::Velocities | State::Parameters | State::Energy);
+    compareStates(s1, s9);
 }
 
 void runPlatformTests() {

platforms/opencl/tests/TestOpenCLCheckpoints.cpp

@@ -120,6 +120,15 @@ void testCheckpoint() {
     integrator2.step(10);
     State s8 = context2.getState(State::Positions | State::Velocities | State::Parameters);
     compareStates(s6, s8);
+    
+    // See if a checkpoint created from one Context can be loaded into a different one.
+    
+    VerletIntegrator integrator3(0.001);
+    Context context3(system, integrator3, platform);
+    stream1.seekg(0, stream1.beg);
+    context3.loadCheckpoint(stream1);
+    State s9 = context3.getState(State::Positions | State::Velocities | State::Parameters | State::Energy);
+    compareStates(s1, s9);
 }
 
 void runPlatformTests() {

platforms/reference/tests/TestReferenceCheckpoints.cpp

@@ -92,6 +92,15 @@ void testCheckpoint() {
     integrator.step(10);
     State s4 = context.getState(State::Positions | State::Velocities | State::Parameters);
     compareStates(s2, s4);
+    
+    // See if a checkpoint created from one Context can be loaded into a different one.
+    
+    VerletIntegrator integrator2(0.001);
+    Context context2(system, integrator2, platform);
+    stream1.seekg(0, stream1.beg);
+    context2.loadCheckpoint(stream1);
+    State s5 = context2.getState(State::Positions | State::Velocities | State::Parameters | State::Energy);
+    compareStates(s1, s5);
 }
 
 void runPlatformTests() {