TestMultipleForces.h

/* -------------------------------------------------------------------------- *
 *                                   OpenMM                                   *
 * -------------------------------------------------------------------------- *
 * This is part of the OpenMM molecular simulation toolkit originating from   *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org.               *
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 * Authors: Peter Eastman                                                     *
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#include "openmm/internal/AssertionUtilities.h"
#include "openmm/Context.h"
#include "ReferencePlatform.h"
#include "openmm/HarmonicAngleForce.h"
#include "openmm/HarmonicBondForce.h"
#include "openmm/PeriodicTorsionForce.h"
#include "openmm/RBTorsionForce.h"
#include "openmm/System.h"
#include "openmm/VerletIntegrator.h"
#include "SimTKOpenMMRealType.h"
#include "sfmt/SFMT.h"
#include <iostream>
#include <vector>

using namespace OpenMM;
using namespace std;

const double TOL = 1e-4;

/**
 * This tests a system with multiple forces, to make sure BondedUtilities is
 * processing them correctly.
 */
void testForces() {
    const int numParticles = 100;
    System system;
    for (int i = 0; i < numParticles; i++)
        system.addParticle(1.0);
    HarmonicBondForce* bonds = new HarmonicBondForce();
    for (int i = 0; i < numParticles-1; i++)
        bonds->addBond(i, i+1, 1.0, 1.5);
    system.addForce(bonds);
    HarmonicAngleForce* angles = new HarmonicAngleForce();
    for (int i = 0; i < numParticles-2; i++)
        angles->addAngle(i, i+1, i+2, 2.0, 1.5);
    system.addForce(angles);
    PeriodicTorsionForce* periodic = new PeriodicTorsionForce();
    for (int i = 0; i < numParticles-3; i++)
        periodic->addTorsion(i, i+1, i+2, i+3, 2, PI_M/3, 1.1);
    system.addForce(periodic);
    RBTorsionForce* rb = new RBTorsionForce();
    for (int i = 0; i < numParticles-3; i += 3)
        rb->addTorsion(i, i+1, i+2, i+3, 1.0, 1.1, 1.2, 0.3, 0.4, 0.5);
    system.addForce(rb);
    ReferencePlatform ref;
    VerletIntegrator integrator1(0.01);
    Context context1(system, integrator1, ref);
    VerletIntegrator integrator2(0.01);
    Context context2(system, integrator2, platform);
    OpenMM_SFMT::SFMT sfmt;
    init_gen_rand(0, sfmt);
    vector<Vec3> positions(numParticles);
    for (int i = 0; i < numParticles; i++)
        positions[i] = Vec3(i, genrand_real2(sfmt), genrand_real2(sfmt));
    context1.setPositions(positions);
    context2.setPositions(positions);
    State state1 = context1.getState(State::Forces | State::Energy);
    State state2 = context2.getState(State::Forces | State::Energy);
    const vector<Vec3>& forces1 = state1.getForces();
    const vector<Vec3>& forces2 = state2.getForces();
    for (int i = 0; i < numParticles; i++)
        ASSERT_EQUAL_VEC(forces1[i], forces2[i], TOL);
    ASSERT_EQUAL_TOL(state1.getPotentialEnergy(), state2.getPotentialEnergy(), TOL);
}

void runPlatformTests();

int main(int argc, char* argv[]) {
    try {
        initializeTests(argc, argv);
        testForces();
        runPlatformTests();
    }
    catch(const exception& e) {
        cout << "exception: " << e.what() << endl;
        return 1;
    }
    cout << "Done" << endl;
    return 0;
}