void MacCormackClamp(FlagGrid& flags, MACGrid& vel, Grid<T>& dst, Grid<T>& orig, Grid<T>& fwd, Real dt)
{
if (flags.isObstacle(i,j,k))
return;
if ( isNotFluid(flags,i,j,k) ) {
dst(i,j,k) = fwd(i,j,k);
return;
}
T dval = dst(i,j,k);
Vec3i upperClamp = flags.getSize() - 1;
// lookup forward/backward
Vec3i posFwd = toVec3i( Vec3(i,j,k) - vel.getCentered(i,j,k) * dt );
Vec3i posBwd = toVec3i( Vec3(i,j,k) + vel.getCentered(i,j,k) * dt );
dval = doClampComponent<T>(upperClamp, orig, dval, posFwd );
// test if lookups point out of grid or into obstacle
if (posFwd.x < 0 || posFwd.y < 0 || posFwd.z < 0 ||
posBwd.x < 0 || posBwd.y < 0 || posBwd.z < 0 ||
posFwd.x > upperClamp.x || posFwd.y > upperClamp.y || ((posFwd.z > upperClamp.z)&&flags.is3D()) ||
posBwd.x > upperClamp.x || posBwd.y > upperClamp.y || ((posBwd.z > upperClamp.z)&&flags.is3D()) ||
flags.isObstacle(posFwd) || flags.isObstacle(posBwd) )
{
dval = fwd(i,j,k);
}
dst(i,j,k) = dval;
}
void MacCormackClampMAC (FlagGrid& flags, MACGrid& vel, MACGrid& dst, MACGrid& orig, MACGrid& fwd, Real dt)
{
if (flags.isObstacle(i,j,k))
return;
if ( isNotFluidMAC(flags,i,j,k) ) {
dst(i,j,k) = fwd(i,j,k);
return;
}
Vec3 pos(i,j,k);
Vec3 dval = dst(i,j,k);
Vec3i upperClamp = flags.getSize() - 1;
// get total fwd lookup
Vec3i posFwd = toVec3i( Vec3(i,j,k) - vel.getCentered(i,j,k) * dt );
Vec3i posBwd = toVec3i( Vec3(i,j,k) + vel.getCentered(i,j,k) * dt );
// clamp individual components
dval.x = doClampComponentMAC<0>(upperClamp, orig, dval.x, toVec3i( pos - vel.getAtMACX(i,j,k) * dt) );
dval.y = doClampComponentMAC<1>(upperClamp, orig, dval.y, toVec3i( pos - vel.getAtMACY(i,j,k) * dt) );
dval.z = doClampComponentMAC<2>(upperClamp, orig, dval.z, toVec3i( pos - vel.getAtMACZ(i,j,k) * dt) );
// test if lookups point out of grid or into obstacle
if (posFwd.x < 0 || posFwd.y < 0 || posFwd.z < 0 ||
posBwd.x < 0 || posBwd.y < 0 || posBwd.z < 0 ||
posFwd.x > upperClamp.x || posFwd.y > upperClamp.y || ((posFwd.z > upperClamp.z)&&flags.is3D()) ||
posBwd.x > upperClamp.x || posBwd.y > upperClamp.y || ((posBwd.z > upperClamp.z)&&flags.is3D())
//|| flags.isObstacle(posFwd) || flags.isObstacle(posBwd) // note - this unfortunately introduces asymmetry... TODO update
)
{
dval = fwd(i,j,k);
}
// writeback
dst(i,j,k) = dval;
}
//! Perform pressure projection of the velocity grid
PYTHON void solvePressure(MACGrid& vel, Grid<Real>& pressure, FlagGrid& flags,
Grid<Real>* phi = 0,
Grid<Real>* perCellCorr = 0,
Real ghostAccuracy = 0,
Real cgMaxIterFac = 1.5,
Real cgAccuracy = 1e-3,
string openBound = "",
string outflow = "",
int outflowHeight = 1,
int precondition = 0,
bool enforceCompatibility = false,
bool useResNorm = true )
{
//assertMsg(vel.is3D(), "Only 3D grids supported so far");
// parse strings
Vector3D<bool> loOpenBound, upOpenBound, loOutflow, upOutflow;
convertDescToVec(openBound, loOpenBound, upOpenBound);
convertDescToVec(outflow, loOutflow, upOutflow);
if (vel.is2D() && (loOpenBound.z || upOpenBound.z))
errMsg("open boundaries for z specified for 2D grid");
// reserve temp grids
Grid<Real> rhs(parent);
Grid<Real> residual(parent);
Grid<Real> search(parent);
Grid<Real> A0(parent);
Grid<Real> Ai(parent);
Grid<Real> Aj(parent);
Grid<Real> Ak(parent);
Grid<Real> tmp(parent);
Grid<Real> pca0(parent);
Grid<Real> pca1(parent);
Grid<Real> pca2(parent);
Grid<Real> pca3(parent);
// setup matrix and boundaries
MakeLaplaceMatrix (flags, A0, Ai, Aj, Ak);
SetOpenBound (A0, Ai, Aj, Ak, vel, loOpenBound, upOpenBound);
if (ghostAccuracy > 0) {
if (!phi) errMsg("solve_pressure: if ghostAccuracy>0, need to specify levelset phi=xxx");
ApplyGhostFluid (flags, A0, *phi, ghostAccuracy);
}
// compute divergence and init right hand side
MakeRhs kernMakeRhs (flags, rhs, vel, perCellCorr);
if (!outflow.empty())
SetOutflow (rhs, loOutflow, upOutflow, outflowHeight);
if (enforceCompatibility)
rhs += (Real)(-kernMakeRhs.sum / (Real)kernMakeRhs.cnt);
// CG
const int maxIter = (int)(cgMaxIterFac * flags.getSize().max());
GridCgInterface *gcg;
if (vel.is3D())
gcg = new GridCg<ApplyMatrix>(pressure, rhs, residual, search, flags, tmp, &A0, &Ai, &Aj, &Ak );
else
gcg = new GridCg<ApplyMatrix2D>(pressure, rhs, residual, search, flags, tmp, &A0, &Ai, &Aj, &Ak );
gcg->setAccuracy( cgAccuracy );
gcg->setUseResNorm( useResNorm );
// optional preconditioning
gcg->setPreconditioner( (GridCgInterface::PreconditionType)precondition, &pca0, &pca1, &pca2, &pca3);
for (int iter=0; iter<maxIter; iter++) {
if (!gcg->iterate()) iter=maxIter;
}
debMsg("FluidSolver::solvePressure iterations:"<<gcg->getIterations()<<", res:"<<gcg->getSigma(), 1);
delete gcg;
if(ghostAccuracy<=0.) {
// ghost fluid off, normal correction
CorrectVelocity (flags, vel, pressure );
} else {
CorrectVelGhostFluid (flags, vel, pressure);
}
}