void testPeriodic() {
// Create a force that uses periodic boundary conditions, then compare to an identical custom force.
System system;
system.setDefaultPeriodicBoxVectors(Vec3(3, 0, 0), Vec3(0, 3, 0), Vec3(0, 0, 3));
int numParticles = 3;
for (int ii = 0; ii < numParticles; ii++)
system.addParticle(1.0);
LangevinIntegrator integrator(0.0, 0.1, 0.01);
AmoebaAngleForce* amoebaAngleForce = new AmoebaAngleForce();
double angle = 100.0;
double quadraticK = 1.0;
double cubicK = 1.0e-01;
double quarticK = 1.0e-02;
double penticK = 1.0e-03;
double sexticK = 1.0e-04;
amoebaAngleForce->addAngle(0, 1, 2, angle, quadraticK);
amoebaAngleForce->setAmoebaGlobalAngleCubic(cubicK);
amoebaAngleForce->setAmoebaGlobalAngleQuartic(quarticK);
amoebaAngleForce->setAmoebaGlobalAnglePentic(penticK);
amoebaAngleForce->setAmoebaGlobalAngleSextic(sexticK);
amoebaAngleForce->setUsesPeriodicBoundaryConditions(true);
system.addForce(amoebaAngleForce);
CustomAngleForce* customForce = new CustomAngleForce("k2*delta^2 + k3*delta^3 + k4*delta^4 + k5*delta^5 + k6*delta^6; delta=theta-theta0");
customForce->addGlobalParameter("theta0", angle*M_PI/180);
customForce->addGlobalParameter("k2", quadraticK*pow(180/M_PI, 2.0));
customForce->addGlobalParameter("k3", cubicK*pow(180/M_PI, 3.0));
customForce->addGlobalParameter("k4", quarticK*pow(180/M_PI, 4.0));
customForce->addGlobalParameter("k5", penticK*pow(180/M_PI, 5.0));
customForce->addGlobalParameter("k6", sexticK*pow(180/M_PI, 6.0));
customForce->addAngle(0, 1, 2);
customForce->setUsesPeriodicBoundaryConditions(true);
customForce->setForceGroup(1);
system.addForce(customForce);
Context context(system, integrator, Platform::getPlatformByName("CUDA"));
std::vector<Vec3> positions(numParticles);
positions[0] = Vec3(0, 1, 0);
positions[1] = Vec3(0, 0, 0);
positions[2] = Vec3(0, 0, 2);
context.setPositions(positions);
State s1 = context.getState(State::Forces | State::Energy, true, 1);
State s2 = context.getState(State::Forces | State::Energy, true, 2);
ASSERT_EQUAL_TOL(s2.getPotentialEnergy(), s1.getPotentialEnergy(), 1e-5);
for (int i = 0; i < numParticles; i++)
ASSERT_EQUAL_VEC(s2.getForces()[i], s1.getForces()[i], 1e-5);
}
void* CustomAngleForceProxy::deserialize(const SerializationNode& node) const {
int version = node.getIntProperty("version");
if (version < 1 || version > 3)
throw OpenMMException("Unsupported version number");
CustomAngleForce* force = NULL;
try {
CustomAngleForce* force = new CustomAngleForce(node.getStringProperty("energy"));
force->setForceGroup(node.getIntProperty("forceGroup", 0));
if (version > 1)
force->setUsesPeriodicBoundaryConditions(node.getBoolProperty("usesPeriodic"));
const SerializationNode& perAngleParams = node.getChildNode("PerAngleParameters");
for (int i = 0; i < (int) perAngleParams.getChildren().size(); i++) {
const SerializationNode& parameter = perAngleParams.getChildren()[i];
force->addPerAngleParameter(parameter.getStringProperty("name"));
}
const SerializationNode& globalParams = node.getChildNode("GlobalParameters");
for (int i = 0; i < (int) globalParams.getChildren().size(); i++) {
const SerializationNode& parameter = globalParams.getChildren()[i];
force->addGlobalParameter(parameter.getStringProperty("name"), parameter.getDoubleProperty("default"));
}
if (version > 2) {
const SerializationNode& energyDerivs = node.getChildNode("EnergyParameterDerivatives");
for (int i = 0; i < (int) energyDerivs.getChildren().size(); i++) {
const SerializationNode& parameter = energyDerivs.getChildren()[i];
force->addEnergyParameterDerivative(parameter.getStringProperty("name"));
}
}
const SerializationNode& angles = node.getChildNode("Angles");
vector<double> params(force->getNumPerAngleParameters());
for (int i = 0; i < (int) angles.getChildren().size(); i++) {
const SerializationNode& angle = angles.getChildren()[i];
for (int j = 0; j < (int) params.size(); j++) {
stringstream key;
key << "param";
key << j+1;
params[j] = angle.getDoubleProperty(key.str());
}
force->addAngle(angle.getIntProperty("p1"), angle.getIntProperty("p2"), angle.getIntProperty("p3"), params);
}
return force;
}
catch (...) {
if (force != NULL)
delete force;
throw;
}
}