void InstanceSurfaceScatterBuilder::generateCandidateStartPoints(std::vector<Point>& points) const
{
uint32_t timeSeed = std::clock();
RNG rng(timeSeed);
Sample2DPacket samples;
if (m_distribution == 0)
{
SamplerPoissonDisc sampleGenerator;
sampleGenerator.generateSamples(samples, m_targetInstanceCount, rng);
}
else if (m_distribution == 1)
{
SamplerStratified sampleGenerator;
sampleGenerator.generateSamples(samples, m_targetInstanceCount, rng);
}
else if (m_distribution == 2)
{
// random
samples.samples.reserve(m_targetInstanceCount);
for (unsigned int i = 0; i < m_targetInstanceCount; i++)
{
float xPos = rng.randomFloat(0.0f, 1.0f);
float yPos = rng.randomFloat(0.0f, 1.0f);
samples.samples.push_back(Sample2D(xPos, yPos));
}
}
// now transform 0.0-1.0 sample pos to X,Z scene world space
std::vector<Sample2D>::const_iterator itSample = samples.samples.begin();
for (; itSample != samples.samples.end(); ++itSample)
{
Sample2D newSample = *itSample;
newSample.x -= 0.5f;
newSample.y -= 0.5f;
newSample.x *= m_width;
newSample.y *= m_depth;
points.push_back(Point(newSample.x, m_raycastStartHeight, newSample.y));
}
}
//---------------------------------------------------------
void CurvedINS2D::INSLiftDrag2D(double ra)
//---------------------------------------------------------
{
// function [Cd, Cl, dP, sw, stri] = INSLiftDrag2D(Ux, Uy, PR, ra, nu, time, tstep, Nsteps)
// Purpose: compute coefficients of lift, drag and pressure drop at cylinder
static FILE* fid;
static DVec sw1, sw2;
static int Nc=0, stri1=0, stri2=0;
if (1 == tstep) {
char buf[50]; sprintf(buf, "liftdraghistory%d.dat", N);
fid = fopen(buf, "w");
fprintf(fid, "timeCdCldP = [...\n");
// Sample location and weights for pressure drop
// Note: the VolkerCylinder test assumes the 2
// sample points (-ra, 0), (ra, 0), are vertices
// located on the internal cylinder boundary
Sample2D(-ra, 0.0, sw1, stri1);
Sample2D( ra, 0.0, sw2, stri2);
Nc = mapC.size()/Nfp;
}
bool bDo=false;
if (1==tstep || tstep==Nsteps || !umMOD(tstep,10)) { bDo=true; }
else if (time > 3.90 && time < 3.96) { bDo=true; } // catch C_d (3.9362)
else if (time > 5.65 && time < 5.73) { bDo=true; } // catch C_l (5.6925)
else if (time > 7.999) { bDo=true; } // catch dP (8.0)
if (!bDo) return;
DVec PRC, nxC, nyC, wv, tv;
DMat dUxdx,dUxdy, dUydx,dUydy, MM1D, V1D;
DMat dUxdxC,dUxdyC, dUydxC,dUydyC, hforce, vforce, sJC;
double dP=0.0, Cd=0.0, Cl=0.0;
dP = sw1.inner(PR(All,stri1)) - sw2.inner(PR(All,stri2));
// compute derivatives
Grad2D(Ux, dUxdx,dUxdy); dUxdxC=dUxdx(vmapC); dUxdyC=dUxdy(vmapC);
Grad2D(Uy, dUydx,dUydy); dUydxC=dUydx(vmapC); dUydyC=dUydy(vmapC);
PRC=PR(vmapC); nxC=nx(mapC); nyC=ny(mapC); sJC=sJ(mapC);
hforce = -PRC.dm(nxC) + nu*( nxC.dm( 2.0 *dUxdxC) + nyC.dm(dUydxC+dUxdyC) );
vforce = -PRC.dm(nyC) + nu*( nxC.dm(dUydxC+dUxdyC) + nyC.dm( 2.0 *dUydyC) );
hforce.reshape(Nfp, Nc);
vforce.reshape(Nfp, Nc);
sJC .reshape(Nfp, Nc);
// compute weights for integrating (1,hforce) and (1,vforce)
V1D = Vandermonde1D(N, r(Fmask(All,1)));
MM1D = trans(inv(V1D)) / V1D;
wv = MM1D.col_sums();
tv = wv*(sJC.dm(hforce)); Cd=tv.sum(); // Compute drag coefficient
tv = wv*(sJC.dm(vforce)); Cl=tv.sum(); // Compute lift coefficient
// Output answers for plotting
fprintf(fid, "%15.14f %15.14f %15.14f %15.14f;...\n", time, Cd/ra, Cl/ra, dP);
fflush(fid);
// LOG report
if (1==tstep || tstep==Nsteps || !umMOD(tstep,Nreport)) {
umLOG(1, "%7d %6.3lf %9.5lf %10.6lf %9.5lf\n",
tstep, time, Cd/ra, Cl/ra, dP);
}
if (tstep==Nsteps) {
fprintf(fid, "];\n");
fclose(fid); fid=NULL;
}
}
