diff options
| -rw-r--r-- | quadtree.go | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/quadtree.go b/quadtree.go index 2aad264..40f308e 100644 --- a/quadtree.go +++ b/quadtree.go @@ -257,7 +257,10 @@ func (n *Node) CalcTotalMass() float64 { return n.TotalMass } +// CalcAllForces calculates the force acting in between the given star and all the other stars using the given theta. +// It gets all the other stars from the root node it is called on func (n Node) CalcAllForces(star Star2D, theta float64) Vec2 { + // initialize a variable storing the overall force var localForce Vec2 = Vec2{} log.Printf("[CalcAllforces] Boundary Width: %f", n.Boundry.Width) @@ -272,13 +275,16 @@ func (n Node) CalcAllForces(star Star2D, theta float64) Vec2 { var localtheta float64 = n.Boundry.Width / distance log.Printf("[CalcAllforces] localtheta=%f", localtheta) - // if the subtree is not empty + // if the subtree is not empty... if n.Subtrees != ([4]*Node{}) { + + // if the local theta is smaller than the given theta threshold... if localtheta < theta { log.Printf("[CalcAllforces] not recursing deeper ++++++++++++++++++++++++ ") // don't recurse further into the tree - // calculate the forces inbetween the star and the node + // calculate the forces in between the star and the node + // define a new star using the center of mass of the new stars nodeStar := Star2D{ C: Vec2{ X: n.CenterOfMass.X, @@ -291,27 +297,41 @@ func (n Node) CalcAllForces(star Star2D, theta float64) Vec2 { M: n.TotalMass, } + // if the star is not equal to the node star, calculate the forces if star != nodeStar { log.Printf("[CalcAllforces] (%v) < +++++++ > (%v)\n", star, nodeStar) + + // calculate the force on the individual star force := CalcForce(star, nodeStar) localForce.X += force.X localForce.Y += force.Y } + // the local theta is bigger than the given theta -> recurse deeper } else { log.Printf("[CalcAllforces] recursing deeper ----------------------------") - // recurse deeper + + // iterate over all the subtrees for i := 0; i < len(n.Subtrees); i++ { force := n.Subtrees[i].CalcAllForces(star, theta) localForce.X += force.X localForce.Y += force.Y } } + + // if the subtree is empty } else { + + // make sure the star in the subtree is not empty if n.Star != (Star2D{}) { + + // if the star is not the star on which the forces should be calculated if star != n.Star { + log.Printf("[CalcAllforces] not recursing deeper ====================== ") log.Printf("[CalcAllforces] (%v) < ------- > (%v)\n", star, n.Star) + + // calculate the forces acting on the star force := CalcForce(star, n.Star) localForce.X += force.X localForce.Y += force.Y @@ -320,8 +340,9 @@ func (n Node) CalcAllForces(star Star2D, theta float64) Vec2 { } log.Printf("[CalcAllforces] localforce: %v +-+-+-+-+-+-+-+-+-+- ", localForce) - return localForce + // return the overall acting force + return localForce } // CalcForce calculates the force exerted on s1 by s2 and returns a vector representing that force |
