/* -------------------------------------------------------------------------- *
 *                                   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.               *
 *                                                                            *
 * Portions copyright (c) 2008-2024 Stanford University and the Authors.      *
 * Authors: Peter Eastman                                                     *
 * Contributors:                                                              *
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 * Software is furnished to do so, subject to the following conditions:       *
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#include "CudaTests.h"
#include "TestNonbondedForce.h"
#include <cuda.h>
#include <string>

void testDeterministicForces() {
    // Check that the CudaDeterministicForces property works correctly.
    
    const int numParticles = 1000;
    System system;
    system.setDefaultPeriodicBoxVectors(Vec3(6, 0, 0), Vec3(2.1, 6, 0), Vec3(-1.5, -0.5, 6));
    NonbondedForce *nonbonded = new NonbondedForce();
    nonbonded->setNonbondedMethod(NonbondedForce::PME);
    system.addForce(nonbonded);
    vector<Vec3> positions;
    OpenMM_SFMT::SFMT sfmt;
    init_gen_rand(0, sfmt);
    for (int i = 0; i < numParticles; i++) {
        system.addParticle(1.0);
        nonbonded->addParticle(i%2 == 0 ? 1 : -1, 1, 0);
        positions.push_back(Vec3(genrand_real2(sfmt)-0.5, genrand_real2(sfmt)-0.5, genrand_real2(sfmt)-0.5)*6);
    }
    VerletIntegrator integrator(0.001);
    map<string, string> properties;
    properties[CudaPlatform::CudaDeterministicForces()] = "true";
    Context context(system, integrator, platform, properties);
    context.setPositions(positions);
    State state1 = context.getState(State::Forces);
    State state2 = context.getState(State::Forces);
    
    // All forces should be *exactly* equal.
    
    for (int i = 0; i < numParticles; i++) {
        ASSERT_EQUAL(state1.getForces()[i][0], state2.getForces()[i][0]);
        ASSERT_EQUAL(state1.getForces()[i][1], state2.getForces()[i][1]);
        ASSERT_EQUAL(state1.getForces()[i][2], state2.getForces()[i][2]);
    }
}

bool canRunHugeTest() {
    // Create a minimal context just to see which device is being used.

    System system;
    system.addParticle(1.0);
    VerletIntegrator integrator(1.0);
    Context context(system, integrator, platform);
    int deviceIndex = stoi(platform.getPropertyValue(context, CudaPlatform::CudaDeviceIndex()));

    // Find out how much memory the device has.

    CUdevice device;
    cuDeviceGet(&device, deviceIndex);
    size_t memory;
    cuDeviceTotalMem(&memory, device);

    // Only run the huge test if the device has at least 4 GB of memory.

    return (memory >= 4L*(1<<30));
}

void runPlatformTests() {
    testParallelComputation(NonbondedForce::NoCutoff);
    testParallelComputation(NonbondedForce::Ewald);
    testParallelComputation(NonbondedForce::PME);
    testParallelComputation(NonbondedForce::LJPME);
    testReordering();
    testDeterministicForces();
    if (canRunHugeTest())
        testHugeSystem();
}
