/**
* Recursively walk the tree to do hackwalk calculation
*/
public override HG walkSubTree(double dsq, HG hg)
{
if (this != hg.pskip)
{
hg = gravSub(hg);
}
return(hg);
}
/**
* Decide if the cell is too close to accept as a single term.
*
* @return true if the cell is too close.
*/
public bool subdivp(double dsq, HG hg)
{
MathVector dr = MathVector.makeMathVector();
dr.subtraction2(pos, hg.pos0);
double drsq = dr.dotProduct();
// in the original olden version drsp is multiplied by 1.0
return(drsq < dsq);
}
/**
* Evaluate gravitational field on the body.
* The original olden version calls a routine named "walkscan",
* but we use the same name that is in the Barnes code.
*/
public void hackGravity(double rsize, Node root)
{
MathVector pos0 = pos.cloneMathVector();
HG hg = HG.makeHG(this, pos);
hg = root.walkSubTree(rsize * rsize, hg);
phi = hg.phi0;
newAcc = hg.acc0;
}
/**
* Compute a single body-body or body-cell interaction
*/
public HG gravSub (HG hg)
{
MathVector dr = MathVector.makeMathVector ();
dr.subtraction2 (pos, hg.pos0);
double drsq = dr.dotProduct () + (EPS * EPS);
double drabs = Math.Sqrt (drsq);
double phii = mass / drabs;
hg.phi0 -= phii;
double mor3 = phii / drsq;
dr.multScalar1 (mor3);
hg.acc0.addition (dr);
return hg;
}
/**
* Compute a single body-body or body-cell interaction
*/
public HG gravSub(HG hg)
{
MathVector dr = MathVector.makeMathVector();
dr.subtraction2(pos, hg.pos0);
double drsq = dr.dotProduct() + (EPS * EPS);
double drabs = Math.Sqrt(drsq);
double phii = mass / drabs;
hg.phi0 -= phii;
double mor3 = phii / drsq;
dr.multScalar1(mor3);
hg.acc0.addition(dr);
return(hg);
}
/**
* Recursively walk the tree to do hackwalk calculation
*/
public override HG walkSubTree(double dsq, HG hg)
{
if (subdivp(dsq, hg))
{
for (int k = 0; k < Cell.NSUB; k++)
{
Node r = this.subp [k];
if (r != null)
{
hg = r.walkSubTree(dsq / 4.0, hg);
}
}
}
else
{
hg = gravSub(hg);
}
return(hg);
}
public abstract HG walkSubTree(double dsq, HG hg);
/**
* Recursively walk the tree to do hackwalk calculation
*/
public override HG walkSubTree (double dsq, HG hg)
{
if (subdivp (dsq, hg)) {
for (int k = 0; k < Cell.NSUB; k++) {
Node r = this.subp [k];
if (r != null)
hg = r.walkSubTree (dsq / 4.0, hg);
}
} else
hg = gravSub (hg);
return hg;
}
/**
* Decide if the cell is too close to accept as a single term.
*
* @return true if the cell is too close.
*/
public bool subdivp (double dsq, HG hg)
{
MathVector dr = MathVector.makeMathVector ();
dr.subtraction2 (pos, hg.pos0);
double drsq = dr.dotProduct ();
// in the original olden version drsp is multiplied by 1.0
return (drsq < dsq);
}
/**
* Recursively walk the tree to do hackwalk calculation
*/
public override HG walkSubTree (double dsq, HG hg)
{
if (this != hg.pskip)
hg = gravSub (hg);
return hg;
}
public abstract HG walkSubTree (double dsq, HG hg);
