void testExclusions() {
System system;
VerletIntegrator integrator(0.01);
CustomNonbondedForce* nonbonded = new CustomNonbondedForce("a*r; a=a1+a2");
nonbonded->addPerParticleParameter("a");
vector<double> params(1);
vector<Vec3> positions(4);
for (int i = 0; i < 4; i++) {
system.addParticle(1.0);
params[0] = i+1;
nonbonded->addParticle(params);
positions[i] = Vec3(i, 0, 0);
}
nonbonded->addExclusion(0, 1);
nonbonded->addExclusion(1, 2);
nonbonded->addExclusion(2, 3);
nonbonded->addExclusion(0, 2);
nonbonded->addExclusion(1, 3);
system.addForce(nonbonded);
Context context(system, integrator, platform);
context.setPositions(positions);
State state = context.getState(State::Forces | State::Energy);
const vector<Vec3>& forces = state.getForces();
ASSERT_EQUAL_VEC(Vec3(1+4, 0, 0), forces[0], TOL);
ASSERT_EQUAL_VEC(Vec3(0, 0, 0), forces[1], TOL);
ASSERT_EQUAL_VEC(Vec3(0, 0, 0), forces[2], TOL);
ASSERT_EQUAL_VEC(Vec3(-(1+4), 0, 0), forces[3], TOL);
ASSERT_EQUAL_TOL((1+4)*3.0, state.getPotentialEnergy(), TOL);
}
void testInteractionGroups() {
const int numParticles = 6;
System system;
VerletIntegrator integrator(0.01);
CustomNonbondedForce* nonbonded = new CustomNonbondedForce("v1+v2");
nonbonded->addPerParticleParameter("v");
vector<double> params(1, 0.001);
for (int i = 0; i < numParticles; i++) {
system.addParticle(1.0);
nonbonded->addParticle(params);
params[0] *= 10;
}
set<int> set1, set2, set3, set4;
set1.insert(2);
set2.insert(0);
set2.insert(1);
set2.insert(2);
set2.insert(3);
set2.insert(4);
set2.insert(5);
nonbonded->addInteractionGroup(set1, set2); // Particle 2 interacts with every other particle.
set3.insert(0);
set3.insert(1);
set4.insert(4);
set4.insert(5);
nonbonded->addInteractionGroup(set3, set4); // Particles 0 and 1 interact with 4 and 5.
nonbonded->addExclusion(1, 2); // Add an exclusion to make sure it gets skipped.
system.addForce(nonbonded);
Context context(system, integrator, platform);
vector<Vec3> positions(numParticles);
context.setPositions(positions);
State state = context.getState(State::Energy);
double expectedEnergy = 331.423; // Each digit is the number of interactions a particle particle is involved in.
ASSERT_EQUAL_TOL(expectedEnergy, state.getPotentialEnergy(), TOL);
}
void* CustomNonbondedForceProxy::deserialize(const SerializationNode& node) const {
if (node.getIntProperty("version") != 1)
throw OpenMMException("Unsupported version number");
CustomNonbondedForce* force = NULL;
try {
CustomNonbondedForce* force = new CustomNonbondedForce(node.getStringProperty("energy"));
force->setNonbondedMethod((CustomNonbondedForce::NonbondedMethod) node.getIntProperty("method"));
force->setCutoffDistance(node.getDoubleProperty("cutoff"));
const SerializationNode& perParticleParams = node.getChildNode("PerParticleParameters");
for (int i = 0; i < (int) perParticleParams.getChildren().size(); i++) {
const SerializationNode& parameter = perParticleParams.getChildren()[i];
force->addPerParticleParameter(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"));
}
const SerializationNode& particles = node.getChildNode("Particles");
vector<double> params(force->getNumPerParticleParameters());
for (int i = 0; i < (int) particles.getChildren().size(); i++) {
const SerializationNode& particle = particles.getChildren()[i];
for (int j = 0; j < (int) params.size(); j++) {
stringstream key;
key << "param";
key << j+1;
params[j] = particle.getDoubleProperty(key.str());
}
force->addParticle(params);
}
const SerializationNode& exclusions = node.getChildNode("Exclusions");
for (int i = 0; i < (int) exclusions.getChildren().size(); i++) {
const SerializationNode& exclusion = exclusions.getChildren()[i];
force->addExclusion(exclusion.getIntProperty("p1"), exclusion.getIntProperty("p2"));
}
const SerializationNode& functions = node.getChildNode("Functions");
for (int i = 0; i < (int) functions.getChildren().size(); i++) {
const SerializationNode& function = functions.getChildren()[i];
const SerializationNode& valuesNode = function.getChildNode("Values");
vector<double> values;
for (int j = 0; j < (int) valuesNode.getChildren().size(); j++)
values.push_back(valuesNode.getChildren()[j].getDoubleProperty("v"));
force->addFunction(function.getStringProperty("name"), values, function.getDoubleProperty("min"), function.getDoubleProperty("max"));
}
return force;
}
catch (...) {
if (force != NULL)
delete force;
throw;
}
}
void testParallelComputation() {
System system;
const int numParticles = 200;
for (int i = 0; i < numParticles; i++)
system.addParticle(1.0);
CustomNonbondedForce* force = new CustomNonbondedForce("4*eps*((sigma/r)^12-(sigma/r)^6); sigma=0.5; eps=1");
vector<double> params;
for (int i = 0; i < numParticles; i++)
force->addParticle(params);
system.addForce(force);
OpenMM_SFMT::SFMT sfmt;
init_gen_rand(0, sfmt);
vector<Vec3> positions(numParticles);
for (int i = 0; i < numParticles; i++)
positions[i] = Vec3(5*genrand_real2(sfmt), 5*genrand_real2(sfmt), 5*genrand_real2(sfmt));
for (int i = 0; i < numParticles; ++i)
for (int j = 0; j < i; ++j) {
Vec3 delta = positions[i]-positions[j];
if (delta.dot(delta) < 0.1)
force->addExclusion(i, j);
}
VerletIntegrator integrator1(0.01);
Context context1(system, integrator1, platform);
context1.setPositions(positions);
State state1 = context1.getState(State::Forces | State::Energy);
VerletIntegrator integrator2(0.01);
string deviceIndex = platform.getPropertyValue(context1, CudaPlatform::CudaDeviceIndex());
map<string, string> props;
props[CudaPlatform::CudaDeviceIndex()] = deviceIndex+","+deviceIndex;
Context context2(system, integrator2, platform, props);
context2.setPositions(positions);
State state2 = context2.getState(State::Forces | State::Energy);
ASSERT_EQUAL_TOL(state1.getPotentialEnergy(), state2.getPotentialEnergy(), 1e-5);
for (int i = 0; i < numParticles; i++)
ASSERT_EQUAL_VEC(state1.getForces()[i], state2.getForces()[i], 1e-5);
}
void testLargeInteractionGroup() {
const int numMolecules = 300;
const int numParticles = numMolecules*2;
const double boxSize = 20.0;
// Create a large system.
System system;
system.setDefaultPeriodicBoxVectors(Vec3(boxSize, 0, 0), Vec3(0, boxSize, 0), Vec3(0, 0, boxSize));
for (int i = 0; i < numParticles; i++)
system.addParticle(1.0);
CustomNonbondedForce* nonbonded = new CustomNonbondedForce("4*eps*((sigma/r)^12-(sigma/r)^6)+138.935456*q/r; q=q1*q2; sigma=0.5*(sigma1+sigma2); eps=sqrt(eps1*eps2)");
nonbonded->addPerParticleParameter("q");
nonbonded->addPerParticleParameter("sigma");
nonbonded->addPerParticleParameter("eps");
vector<Vec3> positions(numParticles);
OpenMM_SFMT::SFMT sfmt;
init_gen_rand(0, sfmt);
vector<double> params(3);
for (int i = 0; i < numMolecules; i++) {
if (i < numMolecules/2) {
params[0] = 1.0;
params[1] = 0.2;
params[2] = 0.1;
nonbonded->addParticle(params);
params[0] = -1.0;
params[1] = 0.1;
nonbonded->addParticle(params);
}
else {
params[0] = 1.0;
params[1] = 0.2;
params[2] = 0.2;
nonbonded->addParticle(params);
params[0] = -1.0;
params[1] = 0.1;
nonbonded->addParticle(params);
}
positions[2*i] = Vec3(boxSize*genrand_real2(sfmt), boxSize*genrand_real2(sfmt), boxSize*genrand_real2(sfmt));
positions[2*i+1] = Vec3(positions[2*i][0]+1.0, positions[2*i][1], positions[2*i][2]);
nonbonded->addExclusion(2*i, 2*i+1);
}
nonbonded->setNonbondedMethod(CustomNonbondedForce::CutoffPeriodic);
system.addForce(nonbonded);
// Compute the forces.
VerletIntegrator integrator(0.01);
Context context(system, integrator, platform);
context.setPositions(positions);
State state1 = context.getState(State::Forces);
// Modify the force so only one particle interacts with everything else.
set<int> set1, set2;
set1.insert(151);
for (int i = 0; i < numParticles; i++)
set2.insert(i);
nonbonded->addInteractionGroup(set1, set2);
context.reinitialize();
context.setPositions(positions);
State state2 = context.getState(State::Forces);
// The force on that one particle should be the same.
ASSERT_EQUAL_VEC(state1.getForces()[151], state2.getForces()[151], 1e-4);
// Modify the interaction group so it includes all interactions. This should now reproduce the original forces
// on all atoms.
for (int i = 0; i < numParticles; i++)
set1.insert(i);
nonbonded->setInteractionGroupParameters(0, set1, set2);
context.reinitialize();
context.setPositions(positions);
State state3 = context.getState(State::Forces);
for (int i = 0; i < numParticles; i++)
ASSERT_EQUAL_VEC(state1.getForces()[i], state3.getForces()[i], 1e-4);
}
void testCoulombLennardJones() {
const int numMolecules = 300;
const int numParticles = numMolecules*2;
const double boxSize = 20.0;
// Create two systems: one with a NonbondedForce, and one using a CustomNonbondedForce to implement the same interaction.
System standardSystem;
System customSystem;
for (int i = 0; i < numParticles; i++) {
standardSystem.addParticle(1.0);
customSystem.addParticle(1.0);
}
NonbondedForce* standardNonbonded = new NonbondedForce();
CustomNonbondedForce* customNonbonded = new CustomNonbondedForce("4*eps*((sigma/r)^12-(sigma/r)^6)+138.935456*q/r; q=q1*q2; sigma=0.5*(sigma1+sigma2); eps=sqrt(eps1*eps2)");
customNonbonded->addPerParticleParameter("q");
customNonbonded->addPerParticleParameter("sigma");
customNonbonded->addPerParticleParameter("eps");
vector<Vec3> positions(numParticles);
vector<Vec3> velocities(numParticles);
OpenMM_SFMT::SFMT sfmt;
init_gen_rand(0, sfmt);
vector<double> params(3);
for (int i = 0; i < numMolecules; i++) {
if (i < numMolecules/2) {
standardNonbonded->addParticle(1.0, 0.2, 0.1);
params[0] = 1.0;
params[1] = 0.2;
params[2] = 0.1;
customNonbonded->addParticle(params);
standardNonbonded->addParticle(-1.0, 0.1, 0.1);
params[0] = -1.0;
params[1] = 0.1;
customNonbonded->addParticle(params);
}
else {
standardNonbonded->addParticle(1.0, 0.2, 0.2);
params[0] = 1.0;
params[1] = 0.2;
params[2] = 0.2;
customNonbonded->addParticle(params);
standardNonbonded->addParticle(-1.0, 0.1, 0.2);
params[0] = -1.0;
params[1] = 0.1;
customNonbonded->addParticle(params);
}
positions[2*i] = Vec3(boxSize*genrand_real2(sfmt), boxSize*genrand_real2(sfmt), boxSize*genrand_real2(sfmt));
positions[2*i+1] = Vec3(positions[2*i][0]+1.0, positions[2*i][1], positions[2*i][2]);
velocities[2*i] = Vec3(genrand_real2(sfmt), genrand_real2(sfmt), genrand_real2(sfmt));
velocities[2*i+1] = Vec3(genrand_real2(sfmt), genrand_real2(sfmt), genrand_real2(sfmt));
standardNonbonded->addException(2*i, 2*i+1, 0.0, 1.0, 0.0);
customNonbonded->addExclusion(2*i, 2*i+1);
}
standardNonbonded->setNonbondedMethod(NonbondedForce::NoCutoff);
customNonbonded->setNonbondedMethod(CustomNonbondedForce::NoCutoff);
standardSystem.addForce(standardNonbonded);
customSystem.addForce(customNonbonded);
VerletIntegrator integrator1(0.01);
VerletIntegrator integrator2(0.01);
Context context1(standardSystem, integrator1, platform);
Context context2(customSystem, integrator2, platform);
context1.setPositions(positions);
context2.setPositions(positions);
context1.setVelocities(velocities);
context2.setVelocities(velocities);
State state1 = context1.getState(State::Forces | State::Energy);
State state2 = context2.getState(State::Forces | State::Energy);
ASSERT_EQUAL_TOL(state1.getPotentialEnergy(), state2.getPotentialEnergy(), 1e-4);
for (int i = 0; i < numParticles; i++) {
ASSERT_EQUAL_VEC(state1.getForces()[i], state2.getForces()[i], 1e-4);
}
}
void* CustomNonbondedForceProxy::deserialize(const SerializationNode& node) const {
int version = node.getIntProperty("version");
if (version < 1 || version > 2)
throw OpenMMException("Unsupported version number");
CustomNonbondedForce* force = NULL;
try {
CustomNonbondedForce* force = new CustomNonbondedForce(node.getStringProperty("energy"));
force->setForceGroup(node.getIntProperty("forceGroup", 0));
force->setNonbondedMethod((CustomNonbondedForce::NonbondedMethod) node.getIntProperty("method"));
force->setCutoffDistance(node.getDoubleProperty("cutoff"));
force->setUseSwitchingFunction(node.getBoolProperty("useSwitchingFunction", false));
force->setSwitchingDistance(node.getDoubleProperty("switchingDistance", -1.0));
force->setUseLongRangeCorrection(node.getBoolProperty("useLongRangeCorrection", false));
const SerializationNode& perParticleParams = node.getChildNode("PerParticleParameters");
for (int i = 0; i < (int) perParticleParams.getChildren().size(); i++) {
const SerializationNode& parameter = perParticleParams.getChildren()[i];
force->addPerParticleParameter(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 > 1) {
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& particles = node.getChildNode("Particles");
vector<double> params(force->getNumPerParticleParameters());
for (int i = 0; i < (int) particles.getChildren().size(); i++) {
const SerializationNode& particle = particles.getChildren()[i];
for (int j = 0; j < (int) params.size(); j++) {
stringstream key;
key << "param";
key << j+1;
params[j] = particle.getDoubleProperty(key.str());
}
force->addParticle(params);
}
const SerializationNode& exclusions = node.getChildNode("Exclusions");
for (int i = 0; i < (int) exclusions.getChildren().size(); i++) {
const SerializationNode& exclusion = exclusions.getChildren()[i];
force->addExclusion(exclusion.getIntProperty("p1"), exclusion.getIntProperty("p2"));
}
const SerializationNode& functions = node.getChildNode("Functions");
for (int i = 0; i < (int) functions.getChildren().size(); i++) {
const SerializationNode& function = functions.getChildren()[i];
if (function.hasProperty("type")) {
force->addTabulatedFunction(function.getStringProperty("name"), function.decodeObject<TabulatedFunction>());
}
else {
// This is an old file created before TabulatedFunction existed.
const SerializationNode& valuesNode = function.getChildNode("Values");
vector<double> values;
for (int j = 0; j < (int) valuesNode.getChildren().size(); j++)
values.push_back(valuesNode.getChildren()[j].getDoubleProperty("v"));
force->addTabulatedFunction(function.getStringProperty("name"), new Continuous1DFunction(values, function.getDoubleProperty("min"), function.getDoubleProperty("max")));
}
}
bool hasInteractionGroups = false; // Older files will be missing this block.
for (int i = 0; i < (int) node.getChildren().size(); i++) {
if (node.getChildren()[i].getName() == "InteractionGroups")
hasInteractionGroups = true;
}
if (hasInteractionGroups) {
const SerializationNode& interactionGroups = node.getChildNode("InteractionGroups");
for (int i = 0; i < (int) interactionGroups.getChildren().size(); i++) {
const SerializationNode& interactionGroup = interactionGroups.getChildren()[i];
// Get set 1.
const SerializationNode& set1node = interactionGroup.getChildNode("Set1");
std::set<int> set1;
for (int j = 0; j < (int) set1node.getChildren().size(); j++)
set1.insert(set1node.getChildren()[j].getIntProperty("index"));
// Get set 2.
const SerializationNode& set2node = interactionGroup.getChildNode("Set2");
std::set<int> set2;
for (int j = 0; j < (int) set2node.getChildren().size(); j++)
set2.insert(set2node.getChildren()[j].getIntProperty("index"));
force->addInteractionGroup(set1, set2);
}
}
return force;
}
catch (...) {
if (force != NULL)
delete force;
throw;
}
}
