Program Listing for File Viscosity_Weiler2018.cpp
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#include "Viscosity_Weiler2018.h"
#include "SPlisHSPlasH/TimeManager.h"
#include "Utilities/Timing.h"
#include "Utilities/Counting.h"
#include "SPlisHSPlasH/Simulation.h"
#include "SPlisHSPlasH/BoundaryModel_Akinci2012.h"
#include "SPlisHSPlasH/BoundaryModel_Koschier2017.h"
#include "SPlisHSPlasH/BoundaryModel_Bender2019.h"
#include "SPlisHSPlasH/Utilities/MathFunctions.h"
using namespace SPH;
using namespace GenParam;
int Viscosity_Weiler2018::ITERATIONS = -1;
int Viscosity_Weiler2018::MAX_ITERATIONS = -1;
int Viscosity_Weiler2018::MAX_ERROR = -1;
int Viscosity_Weiler2018::VISCOSITY_COEFFICIENT_BOUNDARY = -1;
Viscosity_Weiler2018::Viscosity_Weiler2018(FluidModel *model) :
ViscosityBase(model), m_vDiff()
{
m_maxIter = 100;
m_maxError = static_cast<Real>(0.01);
m_iterations = 0;
m_boundaryViscosity = 0.0;
m_tangentialDistanceFactor = static_cast<Real>(0.5);
m_vDiff.resize(model->numParticles(), Vector3r::Zero());
model->addField({ "velocity difference", FieldType::Vector3, [&](const unsigned int i) -> Real* { return &m_vDiff[i][0]; }, true });
}
Viscosity_Weiler2018::~Viscosity_Weiler2018(void)
{
m_model->removeFieldByName("velocity difference");
m_vDiff.clear();
}
void Viscosity_Weiler2018::initParameters()
{
ViscosityBase::initParameters();
VISCOSITY_COEFFICIENT_BOUNDARY = createNumericParameter("viscosityBoundary", "Viscosity coefficient (Boundary)", &m_boundaryViscosity);
setGroup(VISCOSITY_COEFFICIENT_BOUNDARY, "Fluid Model|Viscosity");
setDescription(VISCOSITY_COEFFICIENT_BOUNDARY, "Coefficient for the viscosity force computation at the boundary.");
RealParameter* rparam = static_cast<RealParameter*>(getParameter(VISCOSITY_COEFFICIENT_BOUNDARY));
rparam->setMinValue(0.0);
ITERATIONS = createNumericParameter("viscoIterations", "Iterations", &m_iterations);
setGroup(ITERATIONS, "Fluid Model|Viscosity");
setDescription(ITERATIONS, "Iterations required by the viscosity solver.");
getParameter(ITERATIONS)->setReadOnly(true);
MAX_ITERATIONS = createNumericParameter("viscoMaxIter", "Max. iterations (visco)", &m_maxIter);
setGroup(MAX_ITERATIONS, "Fluid Model|Viscosity");
setDescription(MAX_ITERATIONS, "Max. iterations of the viscosity solver.");
static_cast<NumericParameter<unsigned int>*>(getParameter(MAX_ITERATIONS))->setMinValue(1);
MAX_ERROR = createNumericParameter("viscoMaxError", "Max. visco error", &m_maxError);
setGroup(MAX_ERROR, "Fluid Model|Viscosity");
setDescription(MAX_ERROR, "Max. error of the viscosity solver.");
rparam = static_cast<RealParameter*>(getParameter(MAX_ERROR));
rparam->setMinValue(static_cast<Real>(1e-6));
}
#ifdef USE_AVX
void Viscosity_Weiler2018::matrixVecProd(const Real* vec, Real *result, void *userData)
{
Simulation *sim = Simulation::getCurrent();
Viscosity_Weiler2018 *visco = (Viscosity_Weiler2018*)userData;
FluidModel *model = visco->getModel();
const unsigned int numParticles = model->numActiveParticles();
const unsigned int fluidModelIndex = model->getPointSetIndex();
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const Real h = sim->getSupportRadius();
const Real h2 = h*h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real density0 = model->getDensity0();
const Real mu = visco->m_viscosity * density0;
const Real mub = visco->m_boundaryViscosity * density0;
const Real sphereVolume = static_cast<Real>(4.0 / 3.0 * M_PI) * h2*h;
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
const Scalarf8 d_mu_rho0(d * mu * density0);
const Scalarf8 d_mub(d * mub);
const Scalarf8 h2_001(0.01f*h2);
const Scalarf8 density0_avx(density0);
#pragma omp parallel default(shared)
{
#pragma omp for schedule(static)
for (int i = 0; i < (int)numParticles; i++)
{
const Vector3r &xi = model->getPosition(i);
Vector3r ai;
ai.setZero();
const Real density_i = model->getDensity(i);
const Vector3r &vi = Eigen::Map<const Vector3r>(&vec[3 * i]);
const Vector3f8 xi_avx(xi);
const Vector3f8 vi_avx(vi);
const Scalarf8 density_i_avx(density_i);
const Scalarf8 mi_avx(model->getMass(i));
Vector3f8 delta_ai_avx;
delta_ai_avx.setZero();
// Fluid
forall_fluid_neighbors_in_same_phase_avx(
compute_Vj(model);
compute_Vj_gradW_samephase();
const Scalarf8 density_j_avx = convert_one(&sim->getNeighborList(fluidModelIndex, fluidModelIndex, i)[j], &model->getDensity(0), count);
const Vector3f8 xixj = xi_avx - xj_avx;
const Vector3f8 vj_avx = convertVec_zero(&sim->getNeighborList(fluidModelIndex, fluidModelIndex, i)[j], &vec[0], count);
delta_ai_avx += V_gradW * ((d_mu_rho0 / density_j_avx) * (vi_avx - vj_avx).dot(xixj) / (xixj.squaredNorm() + h2_001));
);
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors_avx(
const Vector3f8 vj_avx = convertVec_zero(&sim->getNeighborList(fluidModelIndex, pid, i)[j], &bm_neighbor->getVelocity(0), count);
const Vector3f8 xixj = xi_avx - xj_avx;
const Vector3f8 gradW = CubicKernel_AVX::gradW(xixj);
const Scalarf8 Vj_avx = convert_zero(&sim->getNeighborList(fluidModelIndex, pid, i)[j], &bm_neighbor->getVolume(0), count);
const Vector3f8 a = gradW * (d_mub * (density0_avx * Vj_avx / density_i_avx) * (vi_avx).dot(xixj) / (xixj.squaredNorm() + h2_001));
delta_ai_avx += a;
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1 * dist;
const Vector3r x2 = xj + t1 * dist;
const Vector3r x3 = xj - t2 * dist;
const Vector3r x4 = xj + t2 * dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * rho * sphereVolume;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = (d * mub * vol * (vi).dot(xix1) / (xix1.squaredNorm() + 0.01*h2)) * gradW1;
const Vector3r a2 = (d * mub * vol * (vi).dot(xix2) / (xix2.squaredNorm() + 0.01*h2)) * gradW2;
const Vector3r a3 = (d * mub * vol * (vi).dot(xix3) / (xix3.squaredNorm() + 0.01*h2)) * gradW3;
const Vector3r a4 = (d * mub * vol * (vi).dot(xix4) / (xix4.squaredNorm() + 0.01*h2)) * gradW4;
ai += a1 + a2 + a3 + a4;
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * Vj;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = (d * mub * vol * (vi).dot(xix1) / (xix1.squaredNorm() + 0.01*h2)) * gradW1;
const Vector3r a2 = (d * mub * vol * (vi).dot(xix2) / (xix2.squaredNorm() + 0.01*h2)) * gradW2;
const Vector3r a3 = (d * mub * vol * (vi).dot(xix3) / (xix3.squaredNorm() + 0.01*h2)) * gradW3;
const Vector3r a4 = (d * mub * vol * (vi).dot(xix4) / (xix4.squaredNorm() + 0.01*h2)) * gradW4;
ai += a1 + a2 + a3 + a4;
}
);
}
}
ai[0] += delta_ai_avx.x().reduce();
ai[1] += delta_ai_avx.y().reduce();
ai[2] += delta_ai_avx.z().reduce();
result[3 * i] = vec[3 * i] - dt / density_i*ai[0];
result[3 * i + 1] = vec[3 * i + 1] - dt / density_i*ai[1];
result[3 * i + 2] = vec[3 * i + 2] - dt / density_i*ai[2];
}
}
}
#else
void Viscosity_Weiler2018::matrixVecProd(const Real* vec, Real *result, void *userData)
{
Simulation *sim = Simulation::getCurrent();
Viscosity_Weiler2018 *visco = (Viscosity_Weiler2018*)userData;
FluidModel *model = visco->getModel();
const unsigned int numParticles = model->numActiveParticles();
const unsigned int fluidModelIndex = model->getPointSetIndex();
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const Real h = sim->getSupportRadius();
const Real h2 = h*h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real density0 = model->getDensity0();
const Real mu = visco->m_viscosity * density0;
const Real mub = visco->m_boundaryViscosity * density0;
const Real sphereVolume = static_cast<Real>(4.0 / 3.0 * M_PI) * h2*h;
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
#pragma omp parallel default(shared)
{
#pragma omp for schedule(static)
for (int i = 0; i < (int)numParticles; i++)
{
const Vector3r &xi = model->getPosition(i);
Vector3r ai;
ai.setZero();
const Real density_i = model->getDensity(i);
const Vector3r &vi = Eigen::Map<const Vector3r>(&vec[3 * i]);
// Fluid
forall_fluid_neighbors_in_same_phase(
const Real density_j = model->getDensity(neighborIndex);
const Vector3r gradW = sim->gradW(xi - xj);
const Vector3r &vj = Eigen::Map<const Vector3r>(&vec[3 * neighborIndex]);
const Vector3r xixj = xi - xj;
ai += d * mu * (model->getMass(neighborIndex) / density_j) * (vi - vj).dot(xixj) / (xixj.squaredNorm() + 0.01*h2) * gradW;
);
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors(
const Vector3r &vj = bm_neighbor->getVelocity(neighborIndex);
const Vector3r xixj = xi - xj;
const Vector3r gradW = sim->gradW(xixj);
const Vector3r a = d * mub * (density0 * bm_neighbor->getVolume(neighborIndex) / density_i) * (vi).dot(xixj) / (xixj.squaredNorm() + 0.01*h2) * gradW;
ai += a;
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1 * dist;
const Vector3r x2 = xj + t1 * dist;
const Vector3r x3 = xj - t2 * dist;
const Vector3r x4 = xj + t2 * dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * rho * sphereVolume;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = d * mub * vol * (vi).dot(xix1) / (xix1.squaredNorm() + 0.01*h2) * gradW1;
const Vector3r a2 = d * mub * vol * (vi).dot(xix2) / (xix2.squaredNorm() + 0.01*h2) * gradW2;
const Vector3r a3 = d * mub * vol * (vi).dot(xix3) / (xix3.squaredNorm() + 0.01*h2) * gradW3;
const Vector3r a4 = d * mub * vol * (vi).dot(xix4) / (xix4.squaredNorm() + 0.01*h2) * gradW4;
ai += a1 + a2 + a3 + a4;
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * Vj;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = d * mub * vol * (vi).dot(xix1) / (xix1.squaredNorm() + 0.01*h2) * gradW1;
const Vector3r a2 = d * mub * vol * (vi).dot(xix2) / (xix2.squaredNorm() + 0.01*h2) * gradW2;
const Vector3r a3 = d * mub * vol * (vi).dot(xix3) / (xix3.squaredNorm() + 0.01*h2) * gradW3;
const Vector3r a4 = d * mub * vol * (vi).dot(xix4) / (xix4.squaredNorm() + 0.01*h2) * gradW4;
ai += a1 + a2 + a3 + a4;
}
);
}
}
result[3 * i] = vec[3 * i] - dt / density_i*ai[0];
result[3 * i + 1] = vec[3 * i + 1] - dt / density_i*ai[1];
result[3 * i + 2] = vec[3 * i + 2] - dt / density_i*ai[2];
}
}
}
#endif
#ifdef USE_BLOCKDIAGONAL_PRECONDITIONER
#ifdef USE_AVX
void Viscosity_Weiler2018::diagonalMatrixElement(const unsigned int i, Matrix3r &result, void *userData)
{
// Diagonal element
Simulation *sim = Simulation::getCurrent();
Viscosity_Weiler2018 *visco = (Viscosity_Weiler2018*)userData;
FluidModel *model = visco->getModel();
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int fluidModelIndex = model->getPointSetIndex();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const Real density0 = model->getDensity0();
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
const Real h = sim->getSupportRadius();
const Real h2 = h * h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real mu = visco->m_viscosity * density0;
const Real mub = visco->m_boundaryViscosity * density0;
const Real sphereVolume = static_cast<Real>(4.0 / 3.0 * M_PI) * h2*h;
const Real density_i = model->getDensity(i);
result.setZero();
const Vector3r &xi = model->getPosition(i);
const Scalarf8 d_mu(d * mu);
const Scalarf8 d_mub(d * mub);
const Scalarf8 h2_001(0.01f*h2);
const Scalarf8 density0_avx(density0);
const Vector3f8 xi_avx(xi);
const Scalarf8 density_i_avx(density_i);
Matrix3f8 res_avx;
res_avx.setZero();
// Fluid
forall_fluid_neighbors_in_same_phase_avx(
const Scalarf8 density_j_avx = convert_one(&sim->getNeighborList(fluidModelIndex, fluidModelIndex, i)[j], &model->getDensity(0), count);
const Vector3f8 xixj = xi_avx - xj_avx;
const Vector3f8 gradW = CubicKernel_AVX::gradW(xixj);
const Scalarf8 mj_avx = convert_zero(model->getMass(0), count); // all particles have the same mass
Matrix3f8 gradW_xij;
dyadicProduct(gradW, xixj, gradW_xij);
res_avx += gradW_xij * (d_mu * (mj_avx / density_j_avx) / (xixj.squaredNorm() + h2_001));
);
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors_avx(
const Vector3f8 xixj = xi_avx - xj_avx;
const Vector3f8 gradW = CubicKernel_AVX::gradW(xixj);
const Scalarf8 Vj_avx = convert_zero(&sim->getNeighborList(fluidModelIndex, pid, i)[j], &bm_neighbor->getVolume(0), count);
Matrix3f8 gradW_xij;
dyadicProduct(gradW, xixj, gradW_xij);
res_avx += gradW_xij * (d_mub * (density0_avx * Vj_avx / density_i_avx) / (xixj.squaredNorm() + h2_001));
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1 * dist;
const Vector3r x2 = xj + t1 * dist;
const Vector3r x3 = xj - t2 * dist;
const Vector3r x4 = xj + t2 * dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * rho * sphereVolume;
// compute forces for both sample point
result += (d * mub * vol / (xix1.squaredNorm() + 0.01*h2)) * (gradW1 * xix1.transpose());
result += (d * mub * vol / (xix2.squaredNorm() + 0.01*h2)) * (gradW2 * xix2.transpose());
result += (d * mub * vol / (xix3.squaredNorm() + 0.01*h2)) * (gradW3 * xix3.transpose());
result += (d * mub * vol / (xix4.squaredNorm() + 0.01*h2)) * (gradW4 * xix4.transpose());
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1 * dist;
const Vector3r x2 = xj + t1 * dist;
const Vector3r x3 = xj - t2 * dist;
const Vector3r x4 = xj + t2 * dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * Vj;
// compute forces for both sample point
result += (d * mub * vol / (xix1.squaredNorm() + 0.01*h2)) * (gradW1 * xix1.transpose());
result += (d * mub * vol / (xix2.squaredNorm() + 0.01*h2)) * (gradW2 * xix2.transpose());
result += (d * mub * vol / (xix3.squaredNorm() + 0.01*h2)) * (gradW3 * xix3.transpose());
result += (d * mub * vol / (xix4.squaredNorm() + 0.01*h2)) * (gradW4 * xix4.transpose());
}
);
}
}
result += res_avx.reduce();
result = Matrix3r::Identity() - (dt / density_i) * result;
}
#else
void Viscosity_Weiler2018::diagonalMatrixElement(const unsigned int i, Matrix3r &result, void *userData)
{
// Diagonal element
Simulation *sim = Simulation::getCurrent();
Viscosity_Weiler2018 *visco = (Viscosity_Weiler2018*)userData;
FluidModel *model = visco->getModel();
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int fluidModelIndex = model->getPointSetIndex();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const Real density0 = model->getDensity0();
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
const Real h = sim->getSupportRadius();
const Real h2 = h*h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real mu = visco->m_viscosity * density0;
const Real mub = visco->m_boundaryViscosity * density0;
const Real sphereVolume = static_cast<Real>(4.0 / 3.0 * M_PI) * h2*h;
const Real density_i = model->getDensity(i);
result.setZero();
const Vector3r &xi = model->getPosition(i);
// Fluid
forall_fluid_neighbors_in_same_phase(
const Real density_j = model->getDensity(neighborIndex);
const Vector3r gradW = sim->gradW(xi - xj);
const Vector3r xixj = xi - xj;
result += d * mu * (model->getMass(neighborIndex) / density_j) / (xixj.squaredNorm() + 0.01*h2) * (gradW * xixj.transpose());
);
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors(
const Vector3r xixj = xi - xj;
const Vector3r gradW = sim->gradW(xixj);
result += d * mub * (density0 * bm_neighbor->getVolume(neighborIndex) / density_i) / (xixj.squaredNorm() + 0.01*h2) * (gradW * xixj.transpose());
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * rho * sphereVolume;
// compute forces for both sample point
result += d * mub * vol / (xix1.squaredNorm() + 0.01*h2) * (gradW1 * xix1.transpose());
result += d * mub * vol / (xix2.squaredNorm() + 0.01*h2) * (gradW2 * xix2.transpose());
result += d * mub * vol / (xix3.squaredNorm() + 0.01*h2) * (gradW3 * xix3.transpose());
result += d * mub * vol / (xix4.squaredNorm() + 0.01*h2) * (gradW4 * xix4.transpose());
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * Vj;
// compute forces for both sample point
result += d * mub * vol / (xix1.squaredNorm() + 0.01*h2) * (gradW1 * xix1.transpose());
result += d * mub * vol / (xix2.squaredNorm() + 0.01*h2) * (gradW2 * xix2.transpose());
result += d * mub * vol / (xix3.squaredNorm() + 0.01*h2) * (gradW3 * xix3.transpose());
result += d * mub * vol / (xix4.squaredNorm() + 0.01*h2) * (gradW4 * xix4.transpose());
}
);
}
}
result = Matrix3r::Identity() - (dt / density_i) * result;
}
#endif
#else
void Viscosity_Weiler2018::diagonalMatrixElement(const unsigned int i, Vector3r &result, void *userData)
{
// Diagonal element
Simulation *sim = Simulation::getCurrent();
Viscosity_Weiler2018 *visco = (Viscosity_Weiler2018*)userData;
FluidModel *model = visco->getModel();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const Real h = sim->getSupportRadius();
const Real h2 = h*h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real density0 = model->getDensity0();
const Real mu = visco->m_viscosity * density0;
const Real mub = visco->m_boundaryViscosity * density0;
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int fluidModelIndex = m_model->getPointSetIndex();
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
const Real sphereVolume = 4.0 / 3.0 * M_PI * h2*h;
const Real density_i = model->getDensity(i);
result.setZero();
const Vector3r &xi = model->getPosition(i);
// Fluid
forall_fluid_neighbors_in_same_phase(
const Real density_j = model->getDensity(neighborIndex);
const Vector3r gradW = sim->gradW(xi - xj);
const Vector3r xixj = xi - xj;
Matrix3r r = d * mu * (model->getMass(neighborIndex) / density_j) / (xixj.squaredNorm() + 0.01*h2) * (gradW * xixj.transpose());
result += r.diagonal();
);
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors(
const Vector3r xixj = xi - xj;
const Vector3r gradW = sim->gradW(xixj);
Matrix3r r = d * mub * (density0 * bm_neighbor->getVolume(neighborIndex) / density_i) / (xixj.squaredNorm() + 0.01*h2) * (gradW * xixj.transpose());
result += r.diagonal();
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > 0.0001)
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = 0.25 * rho * sphereVolume;
// compute forces for both sample point
Matrix3r r = d * mub * vol / (xix1.squaredNorm() + 0.01*h2) * (gradW1 * xix1.transpose());
r += d * mub * vol / (xix2.squaredNorm() + 0.01*h2) * (gradW2 * xix2.transpose());
r += d * mub * vol / (xix3.squaredNorm() + 0.01*h2) * (gradW3 * xix3.transpose());
r += d * mub * vol / (xix4.squaredNorm() + 0.01*h2) * (gradW4 * xix4.transpose());
result += r.diagonal();
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > 0.0001)
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = visco->m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = 0.25 * Vj;
// compute forces for both sample point
Matrix3r r = d * mub * vol / (xix1.squaredNorm() + 0.01*h2) * (gradW1 * xix1.transpose());
r += d * mub * vol / (xix2.squaredNorm() + 0.01*h2) * (gradW2 * xix2.transpose());
r += d * mub * vol / (xix3.squaredNorm() + 0.01*h2) * (gradW3 * xix3.transpose());
r += d * mub * vol / (xix4.squaredNorm() + 0.01*h2) * (gradW4 * xix4.transpose());
result += r.diagonal();
}
);
}
}
result = Vector3r::Ones() - (dt / density_i) * result;
}
#endif
void Viscosity_Weiler2018::step()
{
const int numParticles = (int) m_model->numActiveParticles();
// prevent solver from running with a zero-length vector
if (numParticles == 0)
return;
const Real density0 = m_model->getDensity0();
const Real h = TimeManager::getCurrent()->getTimeStepSize();
// Init linear system solver and preconditioner
MatrixReplacement A(3*m_model->numActiveParticles(), matrixVecProd, (void*) this);
m_solver.preconditioner().init(m_model->numActiveParticles(), diagonalMatrixElement, (void*)this);
m_solver.setTolerance(m_maxError);
m_solver.setMaxIterations(m_maxIter);
m_solver.compute(A);
VectorXr b(3*numParticles);
VectorXr x(3*numParticles);
VectorXr g(3*numParticles);
computeRHS(b, g);
// Solve linear system
START_TIMING("CG solve");
x = m_solver.solveWithGuess(b, g);
m_iterations = (int)m_solver.iterations();
STOP_TIMING_AVG;
INCREASE_COUNTER("Visco iterations", static_cast<Real>(m_iterations));
applyForces(x);
}
void Viscosity_Weiler2018::applyForces(const VectorXr &x)
{
const int numParticles = (int) m_model->numActiveParticles();
Simulation* sim = Simulation::getCurrent();
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const unsigned int fluidModelIndex = m_model->getPointSetIndex();
const Real h = sim->getSupportRadius();
const Real h2 = h*h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real density0 = m_model->getDensity0();
const Real mu = m_viscosity * density0;
const Real mub = m_boundaryViscosity * density0;
const Real sphereVolume = static_cast<Real>(4.0 / 3.0 * M_PI) * h2*h;
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
#pragma omp parallel default(shared)
{
#pragma omp for schedule(static)
for (int i = 0; i < (int)numParticles; i++)
{
// Compute the acceleration from the velocity change
Vector3r &ai = m_model->getAcceleration(i);
const Vector3r newVi(x[3 * i], x[3 * i + 1], x[3 * i + 2]);
ai += (1.0 / dt) * (newVi - m_model->getVelocity(i));
m_vDiff[i] = (newVi - m_model->getVelocity(i));
const Vector3r &xi = m_model->getPosition(i);
const Real density_i = m_model->getDensity(i);
const Real m_i = m_model->getMass(i);
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors(
const Vector3r &vj = bm_neighbor->getVelocity(neighborIndex);
const Vector3r xixj = xi - xj;
const Vector3r gradW = sim->gradW(xixj);
const Vector3r a = d * mub * (density0 * bm_neighbor->getVolume(neighborIndex) / density_i) * (newVi - vj).dot(xixj) / (xixj.squaredNorm() + 0.01*h2) * gradW;
bm_neighbor->addForce(xj, -m_model->getMass(i) / density_i * a);
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1 * dist;
const Vector3r x2 = xj + t1 * dist;
const Vector3r x3 = xj - t2 * dist;
const Vector3r x4 = xj + t2 * dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * rho * sphereVolume;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = d * mub * vol * (newVi - v1).dot(xix1) / (xix1.squaredNorm() + 0.01*h2) * gradW1;
const Vector3r a2 = d * mub * vol * (newVi - v2).dot(xix2) / (xix2.squaredNorm() + 0.01*h2) * gradW2;
const Vector3r a3 = d * mub * vol * (newVi - v3).dot(xix3) / (xix3.squaredNorm() + 0.01*h2) * gradW3;
const Vector3r a4 = d * mub * vol * (newVi - v4).dot(xix4) / (xix4.squaredNorm() + 0.01*h2) * gradW4;
bm_neighbor->addForce(x1, -m_model->getMass(i)/density_i * a1);
bm_neighbor->addForce(x2, -m_model->getMass(i)/density_i * a2);
bm_neighbor->addForce(x3, -m_model->getMass(i)/density_i * a3);
bm_neighbor->addForce(x4, -m_model->getMass(i)/density_i * a4);
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * Vj;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = d * mub * vol * (newVi - v1).dot(xix1) / (xix1.squaredNorm() + 0.01*h2) * gradW1;
const Vector3r a2 = d * mub * vol * (newVi - v2).dot(xix2) / (xix2.squaredNorm() + 0.01*h2) * gradW2;
const Vector3r a3 = d * mub * vol * (newVi - v3).dot(xix3) / (xix3.squaredNorm() + 0.01*h2) * gradW3;
const Vector3r a4 = d * mub * vol * (newVi - v4).dot(xix4) / (xix4.squaredNorm() + 0.01*h2) * gradW4;
bm_neighbor->addForce(x1, -m_model->getMass(i)/density_i * a1);
bm_neighbor->addForce(x2, -m_model->getMass(i)/density_i * a2);
bm_neighbor->addForce(x3, -m_model->getMass(i)/density_i * a3);
bm_neighbor->addForce(x4, -m_model->getMass(i)/density_i * a4);
}
);
}
}
}
}
}
void Viscosity_Weiler2018::computeRHS(VectorXr &b, VectorXr &g)
{
const int numParticles = (int) m_model->numActiveParticles();
Simulation* sim = Simulation::getCurrent();
const unsigned int nFluids = sim->numberOfFluidModels();
const unsigned int nBoundaries = sim->numberOfBoundaryModels();
const unsigned int fluidModelIndex = m_model->getPointSetIndex();
const Real h = sim->getSupportRadius();
const Real h2 = h*h;
const Real dt = TimeManager::getCurrent()->getTimeStepSize();
const Real density0 = m_model->getDensity0();
const Real mu = m_viscosity * density0;
const Real mub = m_boundaryViscosity * density0;
const Real sphereVolume = static_cast<Real>(4.0 / 3.0 * M_PI) * h2*h;
Real d = 10.0;
if (sim->is2DSimulation())
d = 8.0;
// Compute RHS
#pragma omp parallel default(shared)
{
#pragma omp for schedule(static) nowait
for (int i = 0; i < (int)numParticles; i++)
{
const Vector3r &vi = m_model->getVelocity(i);
const Vector3r &xi = m_model->getPosition(i);
const Real density_i = m_model->getDensity(i);
const Real m_i = m_model->getMass(i);
Vector3r bi = Vector3r::Zero();
// Boundary
if (mub != 0.0)
{
if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Akinci2012)
{
forall_boundary_neighbors(
const Vector3r &vj = bm_neighbor->getVelocity(neighborIndex);
const Vector3r xixj = xi - xj;
const Vector3r gradW = sim->gradW(xixj);
const Vector3r a = d * mub * (density0 * bm_neighbor->getVolume(neighborIndex) / density_i) * (vj).dot(xixj) / (xixj.squaredNorm() + 0.01*h2) * gradW;
bi += a;
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Koschier2017)
{
forall_density_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1 * dist;
const Vector3r x2 = xj + t1 * dist;
const Vector3r x3 = xj - t2 * dist;
const Vector3r x4 = xj + t2 * dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * rho * sphereVolume;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = d * mub * vol * (v1).dot(xix1) / (xix1.squaredNorm() + 0.01*h2) * gradW1;
const Vector3r a2 = d * mub * vol * (v2).dot(xix2) / (xix2.squaredNorm() + 0.01*h2) * gradW2;
const Vector3r a3 = d * mub * vol * (v3).dot(xix3) / (xix3.squaredNorm() + 0.01*h2) * gradW3;
const Vector3r a4 = d * mub * vol * (v4).dot(xix4) / (xix4.squaredNorm() + 0.01*h2) * gradW4;
bi += a1 + a2 + a3 + a4;
}
);
}
else if (sim->getBoundaryHandlingMethod() == BoundaryHandlingMethods::Bender2019)
{
forall_volume_maps(
const Vector3r xixj = xi - xj;
Vector3r normal = -xixj;
const Real nl = normal.norm();
if (nl > static_cast<Real>(0.0001))
{
normal /= nl;
Vector3r t1;
Vector3r t2;
MathFunctions::getOrthogonalVectors(normal, t1, t2);
const Real dist = m_tangentialDistanceFactor * h;
const Vector3r x1 = xj - t1*dist;
const Vector3r x2 = xj + t1*dist;
const Vector3r x3 = xj - t2*dist;
const Vector3r x4 = xj + t2*dist;
const Vector3r xix1 = xi - x1;
const Vector3r xix2 = xi - x2;
const Vector3r xix3 = xi - x3;
const Vector3r xix4 = xi - x4;
const Vector3r gradW1 = sim->gradW(xix1);
const Vector3r gradW2 = sim->gradW(xix2);
const Vector3r gradW3 = sim->gradW(xix3);
const Vector3r gradW4 = sim->gradW(xix4);
// each sample point represents the quarter of the volume inside of the boundary
const Real vol = static_cast<Real>(0.25) * Vj;
Vector3r v1;
Vector3r v2;
Vector3r v3;
Vector3r v4;
bm_neighbor->getPointVelocity(x1, v1);
bm_neighbor->getPointVelocity(x2, v2);
bm_neighbor->getPointVelocity(x3, v3);
bm_neighbor->getPointVelocity(x4, v4);
// compute forces for both sample point
const Vector3r a1 = d * mub * vol * (v1).dot(xix1) / (xix1.squaredNorm() + 0.01*h2) * gradW1;
const Vector3r a2 = d * mub * vol * (v2).dot(xix2) / (xix2.squaredNorm() + 0.01*h2) * gradW2;
const Vector3r a3 = d * mub * vol * (v3).dot(xix3) / (xix3.squaredNorm() + 0.01*h2) * gradW3;
const Vector3r a4 = d * mub * vol * (v4).dot(xix4) / (xix4.squaredNorm() + 0.01*h2) * gradW4;
bi += a1 + a2 + a3 + a4;
}
);
}
}
b[3*i] = vi[0] - dt/density_i * bi[0];
b[3*i+1] = vi[1] - dt/density_i * bi[1];
b[3*i+2] = vi[2] - dt/density_i * bi[2];
// Warmstart
g[3 * i] = vi[0] + m_vDiff[i][0];
g[3 * i + 1] = vi[1] + m_vDiff[i][1];
g[3 * i + 2] = vi[2] + m_vDiff[i][2];
}
}
}
void Viscosity_Weiler2018::reset()
{
}
void Viscosity_Weiler2018::performNeighborhoodSearchSort()
{
const unsigned int numPart = m_model->numActiveParticles();
if (numPart == 0)
return;
Simulation *sim = Simulation::getCurrent();
auto const& d = sim->getNeighborhoodSearch()->point_set(m_model->getPointSetIndex());
d.sort_field(&m_vDiff[0]);
}