void Phx::Step(float delta)
{
if(gravitation) // Dodajemy grawitacje
ApplyGravitation();
for(int i=0;i<DynamicList.size();i++) // Liczymy si³y
DynamicList[i]->CalcForces(delta);
SearchForCollisions(); // Szukamy kolizji
for(int i=0;i<Collisions.size();i++) // Liczymy wstêpne dane
Collisions[i]->Initialize(delta,Gravity);
for(int i=0;i<10;i++)
{
for(int i=0;i<Collisions.size();i++)
Resolve(Collisions[i],delta); // Rozwi¹zujemy wszystkie wykryte kolizje
ResolveJoints(delta); // Rozwi¹zujemy po³¹czenia
}
PositionalCorrection(); // Korygujemy pozycje
MoveBodies(delta); // Poruszamy obiekty
for(int i=0;i<DynamicList.size();i++)
DynamicList[i]->CalcForces(delta);
for(int i=0;i<DynamicList.size();i++)
{
DynamicList[i]->force.clear();
DynamicList[i]->torque = 0;
}
}
int main(const int argc, const char** argv) {
// Problem size and other parameters
const int nBodies = (argc > 1 ? atoi(argv[1]) : 16384);
const int nSteps = 10; // Duration of test
const float dt = 0.01f; // Body propagation time step
// Body data stored as an Array of Structures (AoS)
struct BodyType bodies[nBodies];
// Initialize random number generator and bodies
srand(0);
float randmax;
randmax = (float) RAND_MAX;
for(int i = 0; i < nBodies; i++) {
bodies[i].x = ((float) rand())/randmax;
bodies[i].y = ((float) rand())/randmax;
bodies[i].z = ((float) rand())/randmax;
bodies[i].vx = ((float) rand())/randmax;
bodies[i].vy = ((float) rand())/randmax;
bodies[i].vz = ((float) rand())/randmax;
}
// Compute initial center of mass
float comx = 0.0f, comy=0.0f, comz=0.0f;
for (int i=0; i<nBodies; i++) {
comx += bodies[i].x;
comy += bodies[i].y;
comz += bodies[i].z;
}
comx = comx / nBodies;
comy = comy / nBodies;
comz = comz / nBodies;
printf("Initial center of mass: (%g, %g, %g)\n", comx, comy, comz);
// Perform benchmark
printf("\n\033[1mNBODY Version 01\033[0m\n");
printf("\nPropagating %d bodies using 1 thread on %s...\n\n",
nBodies, "CPU");
double rate = 0, dRate = 0; // Benchmarking data
const int skipSteps = 3; // Set this to a positive int to skip warm-up steps
printf("\033[1m%5s %10s %10s %8s\033[0m\n", "Step", "Time, s", "Interact/s", "GFLOP/s"); fflush(stdout);
for (int step = 1; step <= nSteps; step++) {
const double tStart = omp_get_wtime(); // Start timing
MoveBodies(nBodies, bodies, dt);
const double tEnd = omp_get_wtime(); // End timing
// These are for calculating flop rate. It ignores symmetry and
// estimates 20 flops per body-body interaction in MoveBodies
const float HztoInts = (float)nBodies * (float)(nBodies-1) ;
const float HztoGFLOPs = 20.0*1e-9*(float)nBodies*(float)(nBodies-1);
if (step > skipSteps) {
// Collect statistics
rate += HztoGFLOPs / (tEnd - tStart);
dRate += HztoGFLOPs * HztoGFLOPs / ((tEnd-tStart)*(tEnd-tStart));
}
printf("%5d %10.3e %10.3e %8.1f %s\n",
step, (tEnd-tStart), HztoInts/(tEnd-tStart), HztoGFLOPs/(tEnd-tStart), (step<=skipSteps?"*":""));
fflush(stdout);
}
rate/=(double)(nSteps-skipSteps);
dRate=sqrt(fabs(dRate/(double)(nSteps-skipSteps)-rate*rate));
printf("-----------------------------------------------------\n");
printf("\033[1m%s %4s \033[42m%10.1f +- %.1f GFLOP/s\033[0m\n",
"Average performance:", "", rate, dRate);
printf("-----------------------------------------------------\n");
printf("* - warm-up, not included in average\n\n");
// Compute final center of mass
comx = 0.0f; comy=0.0f; comz=0.0f;
for (int i=0; i<nBodies; i++) {
comx += bodies[i].x;
comy += bodies[i].y;
comz += bodies[i].z;
}
comx = comx / nBodies;
comy = comy / nBodies;
comz = comz / nBodies;
printf("Final center of mass: (%g, %g, %g)\n", comx, comy, comz);
}