//------------------------------------------------------------------------------
void Solver::Advance (float timeStep)
{
Timer t;
t.Start();
updateBlendValues();
mFluidHashTable[LOW]->Fill(mFluidParticles[LOW]->ActiveIDs);
mFluidHashTable[HIGH]->Fill(mFluidParticles[HIGH]->ActiveIDs);
computeDensity(LOW);
computeDensity(HIGH);
computeAcceleration(LOW);
computeAcceleration(HIGH);
integrate(HIGH, timeStep/2.0f);
mFluidHashTable[HIGH]->Fill(mFluidParticles[HIGH]->ActiveIDs);
computeDensity(HIGH);
computeAcceleration(HIGH);
integrate(HIGH, timeStep/2.0f);
integrate(LOW, timeStep);
inject();
t.Stop();
std::cout << "#LOW " << mFluidParticles[LOW]->ActiveIDs.size() << " #HIGH "
<< mFluidParticles[HIGH]->ActiveIDs.size() << " #TOTAL: "
<< mFluidParticles[LOW]->ActiveIDs.size() +
mFluidParticles[HIGH]->ActiveIDs.size() << "TIME: "
<< t.GetElapsed() << std::endl;
}
/* Performs one step of Euler Integration
as a result, updates the jello structure */
void Euler(cloth *clothItem)
{
int index;
computeAcceleration(clothItem);
for(int row = 0; row < clothItem->height; row++)
{
for(int col = 0; col < clothItem->width; col++)
{
index = FindIndexInArray(row, col, clothItem->width);
if(index == 0 || index == clothItem->width-1)
continue;
clothItem->positions[index].x += clothItem->tStep * clothItem->velocities[index].x;
clothItem->positions[index].y += clothItem->tStep * clothItem->velocities[index].y;
clothItem->positions[index].z += clothItem->tStep * clothItem->velocities[index].z;
clothItem->velocities[index].x += clothItem->tStep * clothItem->acceleration[index].x;
clothItem->velocities[index].y += clothItem->tStep * clothItem->acceleration[index].y;
clothItem->velocities[index].z += clothItem->tStep * clothItem->acceleration[index].z;
}
}
}
// Update particle acclerations
void updateAccelerations(fluid_particle *fluid_particles,
boundary_particle *boundary_particles, param *params)
{
int num_fluid_particles = params->number_fluid_particles;
int num_boundary_particles = params->number_boundary_particles;
for(int i=0; i<num_fluid_particles; i++) {
double ax = 0.0;
double ay = 0.0;
double az = -9.8;
double3 p_pos = fluid_particles[i].pos;
double3 p_v = fluid_particles[i].v;
double p_density = fluid_particles[i].density;
double p_pressure = fluid_particles[i].pressure;
for(int j=0; j<num_fluid_particles; j++) {
if (i!=j) {
double3 q_pos = fluid_particles[j].pos;
double3 q_v = fluid_particles[j].v;
double q_density = fluid_particles[j].density;
double q_pressure = fluid_particles[j].pressure;
double3 tmp_a = computeAcceleration(p_pos, p_v, p_density,
p_pressure, q_pos, q_v,
q_density, q_pressure, params);
ax += tmp_a.x;
ay += tmp_a.y;
az += tmp_a.z;
}
}
fluid_particles[i].a.x = ax;
fluid_particles[i].a.y = ay;
fluid_particles[i].a.z = az;
}
for(int i=0; i<num_fluid_particles; i++) {
double ax = fluid_particles[i].a.x;
double ay = fluid_particles[i].a.y;
double az = fluid_particles[i].a.z;
double3 p_pos = fluid_particles[i].pos;
for (int j=0; j<num_boundary_particles; j++) {
double3 k_pos = boundary_particles[j].pos;
double3 k_n = boundary_particles[j].n;
double3 tmp_a = computeBoundaryAcceleration(p_pos,k_pos,k_n,
params->smoothing_radius,
params->speed_sound);
ax += tmp_a.x;
ay += tmp_a.y;
az += tmp_a.z;
}
fluid_particles[i].a.x = ax;
fluid_particles[i].a.y = ay;
fluid_particles[i].a.z = az;
}
}
void CSimuVertexRingObj::computeStiffnessMatrix(void)
{
CSparseMatrix33 *pmat = this->getOdeIntegrator()->getSparseMatrix();
if (pmat==NULL) return;
pmat->clear();
const bool needJacobian = true;
computeAcceleration(1, needJacobian);
}
void SPHSystem::step() {
curframe++;
cout << "frame " << curframe << " out of " << params.nframes << endl;
if (curframe < params.nframes) {
for (int i = 0; i < params.nsteps; ++i) {
computeAcceleration();
leapFrog();
checkState();
}
if( params.writeLog )
writeFrame(&pressure[0]);
}
}
/* as a result, updates the chain structure */
void Euler(struct chain * chain)
{
point a[chain->number];
computeAcceleration(chain, a);
for (int i=1; i<=chain->number; i++)
{
chain->p[i].x += chain->dt * chain->v[i].x;
chain->p[i].y += chain->dt * chain->v[i].y;
chain->v[i].x += chain->dt * a[i-1].x;
chain->v[i].y += chain->dt * a[i-1].y;
}
}
void SPHSystem::init() {
curframe = 0;
if( params.writeLog ) {
logstream = ofstream(params.logfile, ios::binary);
// write initial state
writeHeader();
writeFrame(&pressure[0]);
}
// step once
computeAcceleration();
leapFrogStart();
checkState();
}
void Smoke::update(float Pmass)
{
computeAcceleration();
float DeltaTime = ofGetLastFrameTime();
accelerate(DeltaTime);
move(DeltaTime);
// bounceInWindow();
if(position.distance(initalPos)>300.0f)
{
position=initalPos;
}
mass=Pmass;
}
/* as a result, updates the jello structure */
void Euler(struct world * jello)
{
computeAcceleration(jello);
/*printf("A start\n");
for (int i=0; i<particleNum; i++) {
printf("a[%d].x = %f a.y = %f a.z = %f\n",i,jello->a[i][0][0].x,jello->a[i][0][0].y, jello->a[i][0][0].z);
}
printf("\n");*/
for (int i=1; i<particleNum; i++)
{
jello->v[i].x += jello->dt * jello->a[i].x;
jello->v[i].y += jello->dt * jello->a[i].y;
jello->p[i].x += jello->dt * jello->v[i].x;
jello->p[i].y += jello->dt * jello->v[i].y;
}
}
/* as a result, updates the jello structure */
void Euler(struct world * jello)
{
int i,j,k;
point a[8][8][8];
computeAcceleration(jello, a);
for (i=0; i<=7; i++)
for (j=0; j<=7; j++)
for (k=0; k<=7; k++)
{
jello->p[i][j][k].x += jello->dt * jello->v[i][j][k].x;
jello->p[i][j][k].y += jello->dt * jello->v[i][j][k].y;
jello->p[i][j][k].z += jello->dt * jello->v[i][j][k].z;
jello->v[i][j][k].x += jello->dt * a[i][j][k].x;
jello->v[i][j][k].y += jello->dt * a[i][j][k].y;
jello->v[i][j][k].z += jello->dt * a[i][j][k].z;
}
}
/* Performs one step of Euler Integration
as a result, updates the jello structure */
void Euler(struct world * jello)
{
int i,j,k;
point a[8][8][8];
memset( (void*)force, 0, sizeof(force));
memset( (void*)a, 0, sizeof(a));
computeAcceleration(jello, a);
for (i=0; i<=7; i++)
for (j=0; j<=7; j++)
for (k=0; k<=7; k++)
{
jello->p[i][j][k].x += jello->dt * jello->v[i][j][k].x;
jello->p[i][j][k].y += jello->dt * jello->v[i][j][k].y;
jello->p[i][j][k].z += jello->dt * jello->v[i][j][k].z;
jello->v[i][j][k].x += jello->dt * a[i][j][k].x;
jello->v[i][j][k].y += jello->dt * a[i][j][k].y;
jello->v[i][j][k].z += jello->dt * a[i][j][k].z;
}
}
/* as a result, updates the jello structure */
void RK4(cloth *clothItem)
{
int index;
point *F1p, *F1v,
*F2p, *F2v,
*F3p, *F3v,
*F4p, *F4v;
F1p = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F1v = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F2p = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F2v = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F3p = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F3v = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F4p = (point*)calloc(clothItem->cArrayLength, sizeof(point));
F4v = (point*)calloc(clothItem->cArrayLength, sizeof(point));
cloth *buffer = (cloth*)malloc(1 * sizeof(cloth));
CopyToBuffer(buffer, clothItem);
computeAcceleration(clothItem);
for(int row = 0; row < clothItem->height; row++)
{
for(int col = 0; col < clothItem->width; col++)
{
index = FindIndexInArray(row, col, clothItem->width);
// Pin Check
if(gPin == PINNED)
{
if(index == 0 || index == clothItem->width-1)
continue;
}
else if(gPin == UNPINLEFT)
{
if(index == clothItem->width-1)
continue;
}
else if(gPin == UNPINRIGHT)
{
if(index == 0)
continue;
}
pMULTIPLY(clothItem->velocities[index], clothItem->tStep, F1p[index]);
pMULTIPLY(clothItem->acceleration[index], clothItem->tStep, F1v[index]);
pMULTIPLY(F1p[index], 0.5, buffer->positions[index]);
pMULTIPLY(F1v[index], 0.5, buffer->velocities[index]);
pSUM(clothItem->positions[index], buffer->positions[index], buffer->positions[index]);
pSUM(clothItem->velocities[index], buffer->velocities[index], buffer->velocities[index]);
}
}
for(int i= 0; i < clothItem->cArrayLength; i++)
{
pCPY(clothItem->acceleration[i], buffer->acceleration[i]);
}
computeAcceleration(buffer);
for(int row = 0; row < clothItem->height; row++)
{
for(int col = 0; col < clothItem->width; col++)
{
index = FindIndexInArray(row, col, clothItem->width);
// Pin Check
if(gPin == PINNED)
{
if(index == 0 || index == clothItem->width-1)
continue;
}
else if(gPin == UNPINLEFT)
{
if(index == clothItem->width-1)
continue;
}
else if(gPin == UNPINRIGHT)
{
if(index == 0)
continue;
}
pMULTIPLY(buffer->velocities[index], clothItem->tStep, F2p[index]);
pMULTIPLY(buffer->acceleration[index], clothItem->tStep, F2v[index]);
pMULTIPLY(F2p[index], 0.5, buffer->positions[index]);
pMULTIPLY(F2v[index], 0.5, buffer->velocities[index]);
pSUM(clothItem->positions[index], buffer->positions[index], buffer->positions[index]);
pSUM(clothItem->velocities[index], buffer->velocities[index], buffer->velocities[index]);
}
}
computeAcceleration(buffer);
for(int row = 0; row < clothItem->height; row++)
{
for(int col = 0; col < clothItem->width; col++)
{
index = FindIndexInArray(row, col, clothItem->width);
// Pin Check
if(gPin == PINNED)
{
if(index == 0 || index == clothItem->width-1)
continue;
}
else if(gPin == UNPINLEFT)
{
if(index == clothItem->width-1)
continue;
}
else if(gPin == UNPINRIGHT)
{
if(index == 0)
continue;
}
pMULTIPLY(buffer->velocities[index], clothItem->tStep, F3p[index]);
pMULTIPLY(buffer->acceleration[index], clothItem->tStep, F3v[index]);
pMULTIPLY(F3p[index], 0.5, buffer->positions[index]);
pMULTIPLY(F3v[index], 0.5, buffer->velocities[index]);
pSUM(clothItem->positions[index], buffer->positions[index], buffer->positions[index]);
pSUM(clothItem->velocities[index], buffer->velocities[index], buffer->velocities[index]);
}
}
computeAcceleration(buffer);
for(int row = 0; row < clothItem->height; row++)
{
for(int col = 0; col < clothItem->width; col++)
{
index = FindIndexInArray(row, col, clothItem->width);
// Pin Check
if(gPin == PINNED)
{
if(index == 0 || index == clothItem->width-1)
continue;
}
else if(gPin == UNPINLEFT)
{
if(index == clothItem->width-1)
continue;
}
else if(gPin == UNPINRIGHT)
{
if(index == 0)
continue;
}
pMULTIPLY(buffer->velocities[index], clothItem->tStep, F4p[index]);
pMULTIPLY(buffer->acceleration[index], clothItem->tStep, F4v[index]);
pMULTIPLY(F2p[index], 2, buffer->positions[index]);
pMULTIPLY(F3p[index], 2, buffer->velocities[index]);
pSUM(buffer->positions[index], buffer->velocities[index], buffer->positions[index]);
pSUM(buffer->positions[index], F1p[index], buffer->positions[index]);
pSUM(buffer->positions[index], F4p[index], buffer->positions[index]);
pMULTIPLY(buffer->positions[index], 1.0 / 6, buffer->positions[index]);
pSUM(buffer->positions[index], clothItem->positions[index], clothItem->positions[index]);
pMULTIPLY(F2v[index], 2, buffer->positions[index]);
pMULTIPLY(F3v[index], 2, buffer->velocities[index]);
pSUM(buffer->positions[index], buffer->velocities[index], buffer->positions[index]);
pSUM(buffer->positions[index], F1v[index], buffer->positions[index]);
pSUM(buffer->positions[index], F4v[index], buffer->positions[index]);
pMULTIPLY(buffer->positions[index], 1.0 / 6, buffer->positions[index]);
pSUM(buffer->positions[index], clothItem->velocities[index], clothItem->velocities[index]);
}
}
for(int i= 0; i < clothItem->cArrayLength; i++)
{
pCPY(buffer->acceleration[i], clothItem->acceleration[i]);
}
for(int i= 0; i < clothItem->cArrayLength; i++)
{
// Pin Check
if(gPin == PINNED)
{
if(index == 0 || index == clothItem->width-1)
continue;
}
else if(gPin == UNPINLEFT)
{
if(index == clothItem->width-1)
continue;
}
else if(gPin == UNPINRIGHT)
{
if(index == 0)
continue;
}
pMULTIPLY(clothItem->velocities[i], gDelta, underWaterDamp);
pSUM(clothItem->velocities[i], underWaterDamp, clothItem->velocities[i]);
pSUM(clothItem->force[i], gravity, clothItem->force[i]);
}
free(buffer);
return;
}
// Update particle acclerations
void updateAccelerations(fluid_particle *fluid_particles,
boundary_particle *boundary_particles, param *params)
{
int num_fluid_particles = params->number_fluid_particles;
int num_boundary_particles = params->number_boundary_particles;
#pragma acc parallel loop default(present)
for(int i=0; i<num_fluid_particles; i++) {
double ax = 0.0;
double ay = 0.0;
double az = -9.8;
double3 p_pos = fluid_particles[i].pos;
double3 p_v = fluid_particles[i].v;
double p_density = fluid_particles[i].density;
double p_pressure = fluid_particles[i].pressure;
for(int j=0; j<num_fluid_particles; j++) {
if (i!=j) {
double3 q_pos = fluid_particles[j].pos;
double3 q_v = fluid_particles[j].v;
double q_density = fluid_particles[j].density;
double q_pressure = fluid_particles[j].pressure;
double3 tmp_a;
computeAcceleration(&tmp_a, p_pos, p_v, p_density,
p_pressure, q_pos, q_v,
q_density, q_pressure, params[0].smoothing_radius,
params[0].alpha, params[0].speed_sound,
params[0].mass_particle,params[0].surface_tension);
ax += tmp_a.x;
ay += tmp_a.y;
az += tmp_a.z;
}
}
fluid_particles[i].a.x = ax;
fluid_particles[i].a.y = ay;
fluid_particles[i].a.z = az;
}
#pragma acc parallel loop default(present)
for(int i=0; i<num_fluid_particles; i++) {
double ax = fluid_particles[i].a.x;
double ay = fluid_particles[i].a.y;
double az = fluid_particles[i].a.z;
double3 p_pos = fluid_particles[i].pos;
for (int j=0; j<num_boundary_particles; j++) {
double3 k_pos = boundary_particles[j].pos;
double3 k_n = boundary_particles[j].n;
double3 tmp_a;
computeBoundaryAcceleration(&tmp_a, p_pos,k_pos,k_n,
params[0].smoothing_radius,
params[0].speed_sound);
ax += tmp_a.x;
ay += tmp_a.y;
az += tmp_a.z;
}
fluid_particles[i].a.x = ax;
fluid_particles[i].a.y = ay;
fluid_particles[i].a.z = az;
}
}
int main(int argc, char* argv[]){
// domain variables
int iter = 0;
int i;
int file_index;
int max_iter;
double max_time = 1.0;
double dt = .0000001;
double domain_box[4] = {0.0, 0.0, 1.0, 2.0};
double domain_m_box[4] = {.10, 0.2, 0.90, 2.00};
int domain_num_cells[2] = {10, 20};
int pp_cell[2] = {2,2};
double ipart_dim[2];
int domain_num_particles[2];
double test_px, test_py;
char p_filename[40];
char p_filename2[40];
char g_filename[40];
//timing variables
double start_time;
double end_time;
// patch variables
int rank = 0;
int size;
int num_proc[2];
double box[4];
double m_box[4];
int num_cells[2];
int halo_cells[4] = {1,1,1,1};
int num_particles[2];
int sfactor = 2;
GridData grid_data;
Node** grid;
InitialParticleData ipart_data;
Particle* particles;
Particle* post_particles;
Particle* particle_list;
Particle* rhalo_parts[8];
Particle* shalo_parts[8];
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Request halo_req[8][2];
MPI_Status halo_stat[8][2];
max_iter = (int)(max_time/dt);
if(rank == 0){
if(argc == 3){
num_proc[0] = atoi(argv[1]);
num_proc[1] = atoi(argv[2]);
}else if(argc == 6){
num_proc[0] = atoi(argv[1]);
num_proc[1] = atoi(argv[2]);
domain_num_cells[0] = atoi(argv[3]);
domain_num_cells[1] = atoi(argv[4]);
max_iter = atoi(argv[5]);
}
}
MPI_Bcast(num_proc, 2, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Bcast(domain_num_cells, 2, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Bcast(&max_iter, 1, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Barrier(MPI_COMM_WORLD);
grid_data.gravity[0] = 0;
grid_data.gravity[1] = -900.8;
grid_data.cell_dim[0] = (domain_box[2] - domain_box[0])/domain_num_cells[0];
grid_data.cell_dim[1] = (domain_box[3] - domain_box[1])/domain_num_cells[1];
test_px = grid_data.cell_dim[0]/pp_cell[0];
test_py = grid_data.cell_dim[1]/pp_cell[1];
domain_num_particles[0] = (int)((domain_m_box[2] - domain_m_box[0])/test_px);
domain_num_particles[1] = (int)((domain_m_box[3] - domain_m_box[1])/test_py);
ipart_dim[0] = (domain_m_box[2] - domain_m_box[0])/domain_num_particles[0];
ipart_dim[1] = (domain_m_box[3] - domain_m_box[1])/domain_num_particles[1];
decomposeGrid(rank, num_proc, domain_num_cells, num_cells, domain_box, box, halo_cells, &grid_data);
decomposeMaterial(box, domain_m_box, m_box, ipart_dim, num_particles);
ipart_data.density = 1000;
ipart_data.bulk = 3;
ipart_data.shear = 4;
ipart_data.E = 90000;
ipart_data.poisson = .30;
ipart_data.idim[0] = ipart_dim[0];
ipart_data.idim[1] = ipart_dim[1];
ipart_data.velocity[0] = 0;
ipart_data.velocity[1] = 0;
ipart_data.box[0] = m_box[0];
ipart_data.box[1] = m_box[1];
ipart_data.box[2] = m_box[2];
ipart_data.box[3] = m_box[3];
ipart_data.num_particles[0] = num_particles[0];
ipart_data.num_particles[1] = num_particles[1];
ipart_data.domain_num_particles[0] = domain_num_particles[0];
ipart_data.domain_num_particles[1] = domain_num_particles[1];
grid = createGrid(&grid_data, box, num_cells);
particles = createMaterial(&grid_data, &ipart_data);
post_particles = createMaterial(&grid_data, &ipart_data);
initializeGrid(&grid_data, grid);
initializeMaterial(&grid_data, &ipart_data, particles);
//allocate halo particles
allocateHaloParticles(&grid_data, sfactor, pp_cell, rhalo_parts, shalo_parts);
file_index = 0;
start_time = MPI_Wtime();
for(iter = 0; iter <= max_iter; iter++){
gatherHaloParticles(&grid_data, particles, rhalo_parts, shalo_parts);
sendRecvParticles(&grid_data, rhalo_parts, shalo_parts);
clearGridValues(&grid_data, grid);
mapToGrid(&grid_data, grid, particles);
for(i = 0; i < 8; i++){
if(grid_data.rank[i] >= 0 && rhalo_parts[i][0].particle_count > 0){
mapToGrid(&grid_data, grid, rhalo_parts[i]);
}
}
momentumToVelocityOnGrid(&grid_data, grid);
computeForces(&grid_data, grid, particles);
for(i = 0; i < 8; i++){
if(grid_data.rank[i] >= 0 && rhalo_parts[i][0].particle_count > 0){
computeForces(&grid_data, grid, rhalo_parts[i]);
}
}
computeAcceleration(&grid_data, grid);
/**
particle_list = gatherParticles(rank, size, domain_num_particles[0] * domain_num_particles[1],
particles, post_particles);
if(rank == 0){
//if(iter%100 == 0){
sprintf(p_filename, "ppart%06d.vtk", file_index);
//sprintf(p_filename2, "center%06d.vtk", file_index);
//sprintf(g_filename, "grid_output%06d.vtk", file_index);
//writeParticlesVtkFile(&grid_data, grid, rhalo_parts[0], p_filename);
writeParticlesVtkFile(&grid_data, grid, particle_list, p_filename);
//writeParticlesVtkFile(&grid_data, grid, particle_list, p_filename);
//writeParticlesVtkFile(&grid_data, grid, particles, p_filename);
//writeGridVtkFile(&grid_data, grid, g_filename);
//writeGridVtkFile(&grid_data, grid, g_filename);
//free(particle_list);
file_index++;
//}
}
**/
updateNodalValues(&grid_data, grid, dt);
updateStressAndStrain(&grid_data, grid, particles, dt);
pUpdateParticlePosition(&grid_data, grid, particles, post_particles, shalo_parts, dt);
sendRecvParticles(&grid_data, rhalo_parts, shalo_parts);
updateParticleList(&grid_data, particles, rhalo_parts);
/**
particle_list = gatherParticles(rank, size, domain_num_particles[0] * domain_num_particles[1],
particles, post_particles);
if(rank == 0){
sprintf(p_filename, "particle_output%06d.vtk", file_index);
file_index++;
//sprintf(g_filename, "grid_output%06d.vtk", file_index);
writeParticlesVtkFile(&grid_data, grid, particles, p_filename);
//writeParticlesVtkFile(&grid_data, grid, particle_list, p_filename);
//writeParticlesVtkFile(&grid_data, grid, particles, p_filename);
//writeGridVtkFile(&grid_data, grid, g_filename);
free(particle_list);
}
**/
MPI_Barrier(MPI_COMM_WORLD);
}
end_time = MPI_Wtime();
MPI_Barrier(MPI_COMM_WORLD);
//particle_list = gatherParticles(rank, size, domain_num_particles[0] * domain_num_particles[1],
// particles, post_particles);
if(rank == 0){
printf("Parallel, np: %d, iterations: %d, time: %f\n", size, max_iter, end_time-start_time);
//writeParticlesVtkFile(&grid_data, grid, particle_list, "pparts.vtk");
//free(particle_list);
}
freeGrid(grid, &grid_data);
freeMaterial(particles);
freeMaterial(post_particles);
freeHaloParticles(&grid_data, rhalo_parts, shalo_parts);
//MPI_Barrier(MPI_COMM_WORLD);
MPI_Finalize();
return 0;
}
void RK4(struct world * jello)
{
point F1p[999], F1v[999],
F2p[999], F2v[999],
F3p[999], F3v[999],
F4p[999], F4v[999];
struct world buffer;
int i,j,k;
buffer = *jello; // make a copy of jello
computeAcceleration(jello);
for (i=0; i<particleNum; i++){
pMULTIPLY(jello->v[i],jello->dt,F1p[i]);
pMULTIPLY(jello->a[i],jello->dt,F1v[i]);
pMULTIPLY(F1p[i],0.5,buffer.p[i]);
pMULTIPLY(F1v[i],0.5,buffer.v[i]);
pSUM(jello->p[i],buffer.p[i],buffer.p[i]);
pSUM(jello->v[i],buffer.v[i],buffer.v[i]);
}
computeAcceleration(&buffer);
for (i=0; i<particleNum; i++){
// F2p = dt * buffer.v;
pMULTIPLY(buffer.v[i],jello->dt,F2p[i]);
// F2v = dt * a(buffer.p,buffer.v);
pMULTIPLY(buffer.a[i],jello->dt,F2v[i]);
pMULTIPLY(F2p[i],0.5,buffer.p[i]);
pMULTIPLY(F2v[i],0.5,buffer.v[i]);
pSUM(jello->p[i],buffer.p[i],buffer.p[i]);
pSUM(jello->v[i],buffer.v[i],buffer.v[i]);
}
computeAcceleration(&buffer);
for (i=0; i<particleNum; i++)
{
// F3p = dt * buffer.v;
pMULTIPLY(buffer.v[i],jello->dt,F3p[i]);
// F3v = dt * a(buffer.p,buffer.v);
pMULTIPLY(buffer.a[i],jello->dt,F3v[i]);
pMULTIPLY(F3p[i],0.5,buffer.p[i]);
pMULTIPLY(F3v[i],0.5,buffer.v[i]);
pSUM(jello->p[i],buffer.p[i],buffer.p[i]);
pSUM(jello->v[i],buffer.v[i],buffer.v[i]);
}
computeAcceleration(&buffer);
for (i=0; i<particleNum; i++)
{
// F3p = dt * buffer.v;
pMULTIPLY(buffer.v[i],jello->dt,F4p[i]);
// F3v = dt * a(buffer.p,buffer.v);
pMULTIPLY(jello->a[i],jello->dt,F4v[i]);
pMULTIPLY(F2p[i],2,buffer.p[i]);
pMULTIPLY(F3p[i],2,buffer.v[i]);
pSUM(buffer.p[i],buffer.v[i],buffer.p[i]);
pSUM(buffer.p[i],F1p[i],buffer.p[i]);
pSUM(buffer.p[i],F4p[i],buffer.p[i]);
pMULTIPLY(buffer.p[i],1.0 / 6,buffer.p[i]);
pSUM(buffer.p[i],jello->p[i],jello->p[i]);
pMULTIPLY(F2v[i],2,buffer.p[i]);
pMULTIPLY(F3v[i],2,buffer.v[i]);
pSUM(buffer.p[i],buffer.v[i],buffer.p[i]);
pSUM(buffer.p[i],F1v[i],buffer.p[i]);
pSUM(buffer.p[i],F4v[i],buffer.p[i]);
pMULTIPLY(buffer.p[i],1.0 / 6,buffer.p[i]);
pSUM(buffer.p[i],jello->v[i],jello->v[i]);
}
return;
}
/* as a result, updates the chain structure */
void RK4(struct chain * chain)
{
point F1p[chain->number], F1v[chain->number],
F2p[chain->number], F2v[chain->number],
F3p[chain->number], F3v[chain->number],
F4p[chain->number], F4v[chain->number];
point a[chain->number];
struct chain buffer = *chain;
computeAcceleration(chain, a);
for (int i=1; i<=chain->number; i++)
{
pMULTIPLY(chain->v[i],chain->dt,F1p[i-1]);
pMULTIPLY(a[i-1],chain->dt,F1v[i-1]);
pMULTIPLY(F1p[i-1],0.5,buffer.p[i]);
pMULTIPLY(F1v[i-1],0.5,buffer.v[i]);
pSUM(chain->p[i],buffer.p[i],buffer.p[i]);
pSUM(chain->v[i],buffer.v[i],buffer.v[i]);
}
computeAcceleration(&buffer, a);
for (int i=1; i<=chain->number; i++)
{
// F2p = dt * buffer.v;
pMULTIPLY(buffer.v[i], chain->dt, F2p[i-1]);
// F2v = dt * a(buffer.p,buffer.v);
pMULTIPLY(a[i-1], chain->dt, F2v[i-1]);
pMULTIPLY(F2p[i-1], 0.5, buffer.p[i]);
pMULTIPLY(F2v[i-1], 0.5, buffer.v[i]);
pSUM(chain->p[i], buffer.p[i], buffer.p[i]);
pSUM(chain->v[i], buffer.v[i], buffer.v[i]);
}
computeAcceleration(&buffer, a);
for (int i=1; i<=chain->number; i++)
{
// F3p = dt * buffer.v;
pMULTIPLY(buffer.v[i], chain->dt, F3p[i-1]);
// F3v = dt * a(buffer.p,buffer.v);
pMULTIPLY(a[i-1], chain->dt, F3v[i-1]);
pMULTIPLY(F3p[i-1], 0.5, buffer.p[i]);
pMULTIPLY(F3v[i-1], 0.5, buffer.v[i]);
pSUM(chain->p[i], buffer.p[i], buffer.p[i]);
pSUM(chain->v[i], buffer.v[i], buffer.v[i]);
}
computeAcceleration(&buffer, a);
for (int i=1; i<=chain->number; i++)
{
// F3p = dt * buffer.v;
pMULTIPLY(buffer.v[i], chain->dt, F4p[i-1]);
// F3v = dt * a(buffer.p,buffer.v);
pMULTIPLY(a[i-1], chain->dt, F4v[i-1]);
pMULTIPLY(F2p[i-1], 2, buffer.p[i]);
pMULTIPLY(F3p[i-1], 2, buffer.v[i]);
pSUM(buffer.p[i], buffer.v[i], buffer.p[i]);
pSUM(buffer.p[i], F1p[i-1], buffer.p[i]);
pSUM(buffer.p[i], F4p[i-1], buffer.p[i]);
pMULTIPLY(buffer.p[i], 1.0 / 6, buffer.p[i]);
pSUM(buffer.p[i], chain->p[i], chain->p[i]);
pMULTIPLY(F2v[i-1], 2, buffer.p[i]);
pMULTIPLY(F3v[i-1], 2, buffer.v[i]);
pSUM(buffer.p[i], buffer.v[i], buffer.p[i]);
pSUM(buffer.p[i], F1v[i-1], buffer.p[i]);
pSUM(buffer.p[i], F4v[i-1], buffer.p[i]);
pMULTIPLY(buffer.p[i], 1.0 / 6, buffer.p[i]);
pSUM(buffer.p[i], chain->v[i], chain->v[i]);
}
return;
}
/* as a result, updates the jello structure */
void RK4(struct world * jello)
{
point F1p[8][8][8], F1v[8][8][8],
F2p[8][8][8], F2v[8][8][8],
F3p[8][8][8], F3v[8][8][8],
F4p[8][8][8], F4v[8][8][8];
point a[8][8][8];
struct world buffer;
int i,j,k;
buffer = *jello; // make a copy of jello
computeAcceleration(jello, a);
for (i=0; i<=7; i++)
for (j=0; j<=7; j++)
for (k=0; k<=7; k++)
{
pMULTIPLY(jello->v[i][j][k],jello->dt,F1p[i][j][k]);
pMULTIPLY(a[i][j][k],jello->dt,F1v[i][j][k]);
pMULTIPLY(F1p[i][j][k],0.5,buffer.p[i][j][k]);
pMULTIPLY(F1v[i][j][k],0.5,buffer.v[i][j][k]);
pSUM(jello->p[i][j][k],buffer.p[i][j][k],buffer.p[i][j][k]);
pSUM(jello->v[i][j][k],buffer.v[i][j][k],buffer.v[i][j][k]);
}
computeAcceleration(&buffer, a);
for (i=0; i<=7; i++)
for (j=0; j<=7; j++)
for (k=0; k<=7; k++)
{
// F2p = dt * buffer.v;
pMULTIPLY(buffer.v[i][j][k],jello->dt,F2p[i][j][k]);
// F2v = dt * a(buffer.p,buffer.v);
pMULTIPLY(a[i][j][k],jello->dt,F2v[i][j][k]);
pMULTIPLY(F2p[i][j][k],0.5,buffer.p[i][j][k]);
pMULTIPLY(F2v[i][j][k],0.5,buffer.v[i][j][k]);
pSUM(jello->p[i][j][k],buffer.p[i][j][k],buffer.p[i][j][k]);
pSUM(jello->v[i][j][k],buffer.v[i][j][k],buffer.v[i][j][k]);
}
computeAcceleration(&buffer, a);
for (i=0; i<=7; i++)
for (j=0; j<=7; j++)
for (k=0; k<=7; k++)
{
// F3p = dt * buffer.v;
pMULTIPLY(buffer.v[i][j][k],jello->dt,F3p[i][j][k]);
// F3v = dt * a(buffer.p,buffer.v);
pMULTIPLY(a[i][j][k],jello->dt,F3v[i][j][k]);
pMULTIPLY(F3p[i][j][k],0.5,buffer.p[i][j][k]);
pMULTIPLY(F3v[i][j][k],0.5,buffer.v[i][j][k]);
pSUM(jello->p[i][j][k],buffer.p[i][j][k],buffer.p[i][j][k]);
pSUM(jello->v[i][j][k],buffer.v[i][j][k],buffer.v[i][j][k]);
}
computeAcceleration(&buffer, a);
for (i=0; i<=7; i++)
for (j=0; j<=7; j++)
for (k=0; k<=7; k++)
{
// F3p = dt * buffer.v;
pMULTIPLY(buffer.v[i][j][k],jello->dt,F4p[i][j][k]);
// F3v = dt * a(buffer.p,buffer.v);
pMULTIPLY(a[i][j][k],jello->dt,F4v[i][j][k]);
pMULTIPLY(F2p[i][j][k],2,buffer.p[i][j][k]);
pMULTIPLY(F3p[i][j][k],2,buffer.v[i][j][k]);
pSUM(buffer.p[i][j][k],buffer.v[i][j][k],buffer.p[i][j][k]);
pSUM(buffer.p[i][j][k],F1p[i][j][k],buffer.p[i][j][k]);
pSUM(buffer.p[i][j][k],F4p[i][j][k],buffer.p[i][j][k]);
pMULTIPLY(buffer.p[i][j][k],1.0 / 6,buffer.p[i][j][k]);
pSUM(buffer.p[i][j][k],jello->p[i][j][k],jello->p[i][j][k]);
pMULTIPLY(F2v[i][j][k],2,buffer.p[i][j][k]);
pMULTIPLY(F3v[i][j][k],2,buffer.v[i][j][k]);
pSUM(buffer.p[i][j][k],buffer.v[i][j][k],buffer.p[i][j][k]);
pSUM(buffer.p[i][j][k],F1v[i][j][k],buffer.p[i][j][k]);
pSUM(buffer.p[i][j][k],F4v[i][j][k],buffer.p[i][j][k]);
pMULTIPLY(buffer.p[i][j][k],1.0 / 6,buffer.p[i][j][k]);
pSUM(buffer.p[i][j][k],jello->v[i][j][k],jello->v[i][j][k]);
}
return;
}