private static Fxyf FromHploc(Hploc loc)
{
Fxyf temp = new Fxyf();
double z = loc.z, phi = loc.phi;
double za = Math.Abs(z);
double tt = HealpixUtils.fmodulo((phi * Fxyf.inv_halfpi), 4.0); // in [0,4)
if (za <= Fxyf.twothird) // Equatorial region
{
double temp1 = 0.5 + tt;
double temp2 = z * 0.75;
double jp = temp1 - temp2; // index of ascending edge line
double jm = temp1 + temp2; // index of descending edge line
long ifp = (long)jp; // in {0,4}
long ifm = (long)jm;
long face_num = (ifp == ifm) ? (ifp | 4) : ((ifp < ifm) ? ifp : (ifm + 8));
temp.fx = HealpixUtils.fmodulo(jm, 1d);
temp.fy = 1d - HealpixUtils.fmodulo(jp, 1d);
temp.face = (int)face_num;
}
else // polar region, za > 2/3
{
int ntt = Math.Min(3, (int)tt);
double tp = tt - ntt;
double tmp;
if ((za < 0.99) || (!loc.have_sth))
{
tmp = Math.Sqrt(3 * (1 - za));
}
else
{
tmp = loc.sth / Math.Sqrt((1d + za) / 3d);
}
double jp = tp * tmp; // increasing edge line index
double jm = (1.0 - tp) * tmp; // decreasing edge line index
if (jp >= 1d)
{
jp = 1d; // for points too close to the boundary
}
if (jm >= 1d)
{
jm = 1d;
}
if (z >= 0)
{
temp.fx = 1d - jm; temp.fy = 1d - jp; temp.face = ntt;
}
else
{
temp.fx = jp; temp.fy = jm; temp.face = ntt + 8;
}
}
return(temp);
}
public static Hploc Create(Vector3d v)
{
Hploc temp = new Hploc();
double xl = 1 / v.Length();
temp.z = v.Z * xl;
temp.phi = FastMath.atan2(v.Y, v.X);
if (Math.Abs(temp.z) > 0.99)
{
temp.sth = Math.Sqrt(v.X * v.X + v.Y * v.Y) * xl;
temp.have_sth = true;
}
return(temp);
}
protected Hploc toHploc()
{
Hploc loc = new Hploc();
double jr = jrll[face] - fx - fy;
double nr; double tmp;
if (jr < 1)
{
nr = jr;
tmp = nr * nr / 3d;
loc.z = 1 - tmp;
if (loc.z > 0.99)
{
loc.sth = Math.Sqrt(tmp * (2d - tmp)); loc.have_sth = true;
}
}
else if (jr > 3)
{
nr = 4 - jr;
tmp = nr * nr / 3d;
loc.z = tmp - 1;
if (loc.z < -0.99)
{
loc.sth = Math.Sqrt(tmp * (2d - tmp)); loc.have_sth = true;
}
}
else
{
nr = 1;
loc.z = (2 - jr) * 2d / 3d;
}
tmp = jpll[face] * nr + fx - fy;
if (tmp < 0)
{
tmp += 8;
}
if (tmp >= 8)
{
tmp -= 8;
}
loc.phi = (nr < 1e-15) ? 0 : (0.5 * Fxyf.halfpi * tmp) / nr;
return(loc);
}
public static Fxyf FromVector(Vector3d v)
{
return(Fxyf.FromHploc(Hploc.Create(v)));
}