void _runBenchmark(int iterations)
{
// once without timing to prime the device
if (!useCpu)
{
m_nbody->update(activeParams.m_timestep);
}
if (useCpu)
{
sdkCreateTimer(&timer);
sdkStartTimer(&timer);
}
else
{
checkCudaErrors(cudaEventRecord(startEvent, 0));
}
for (int i = 0; i < iterations; ++i)
{
m_nbody->update(activeParams.m_timestep);
}
float milliseconds = 0;
if (useCpu)
{
sdkStopTimer(&timer);
milliseconds = sdkGetTimerValue(&timer);
sdkStartTimer(&timer);
}
else
{
checkCudaErrors(cudaEventRecord(stopEvent, 0));
checkCudaErrors(cudaEventSynchronize(stopEvent));
checkCudaErrors(cudaEventElapsedTime(&milliseconds, startEvent, stopEvent));
}
double interactionsPerSecond = 0;
double gflops = 0;
computePerfStats(interactionsPerSecond, gflops, milliseconds, iterations);
printf("%d bodies, total time for %d iterations: %.3f ms, mean %f\n",
numBodies, iterations, milliseconds, milliseconds/iterations);
printf("= %.3f billion interactions per second\n", interactionsPerSecond);
printf("= %.3f %s-precision GFLOP/s at %d flops per interaction\n", gflops,
(sizeof(T) > 4) ? "double" : "single", flopsPerInteraction);
}
bool _compareResults(int numBodies)
{
assert(m_nbodyCuda);
bool passed = true;
m_nbody->update(0.001f);
{
m_nbodyCpu = new BodySystemCPU<T>(numBodies);
m_nbodyCpu->setArray(BODYSYSTEM_POSITION, m_hPos);
m_nbodyCpu->setArray(BODYSYSTEM_VELOCITY, m_hVel);
m_nbodyCpu->update(0.001f);
T *cudaPos = m_nbodyCuda->getArray(BODYSYSTEM_POSITION);
T *cpuPos = m_nbodyCpu->getArray(BODYSYSTEM_POSITION);
T tolerance = 0.0005f;
for (int i = 0; i < numBodies; i++)
{
if (fabs(cpuPos[i] - cudaPos[i]) > tolerance)
{
passed = false;
printf("Error: (host)%f != (device)%f\n", cpuPos[i], cudaPos[i]);
}
}
}
return passed;
}
//---------------------------------------------------------------------
// Orbital Simulator
// This program currently runs an N-body simulation using a basic
// brute force algorithm and renders the bodies onto the screen. Future
// additions include an implementation of the Barnes-Hut algorithm,
// generation of large-N systems, and path trajectory/maneuver
// calculations. See the README for more info.
//---------------------------------------------------------------------
int main()
{
sf::RenderWindow window(sf::VideoMode(orbutil::SCREEN_WIDTH, orbutil::SCREEN_HEIGHT), "Orbit Simulator");
sf::Clock clock;
sf::Time timeSinceLastUpdate;
BodySystem system;
while (window.isOpen())
{
sf::Event event;
while (window.pollEvent(event))
{
if (event.type == sf::Event::Closed)
window.close();
else if (event.type == sf::Event::KeyPressed)
{
if (event.key.code == sf::Keyboard::Escape)
window.close();
}
}
timeSinceLastUpdate = clock.restart();
system.update(timeSinceLastUpdate);
window.clear();
window.draw(system);
window.display();
}
return 0;
}