* foce computation

e00fa29c · Paul Heinzlreiter · 2ac8fcd2 · e00fa29c · e00fa29c · e00fa29c
Commit e00fa29c authored 8 years ago by Paul Heinzlreiter
--- a/bh_tree_mpi/datastructures/Body.cpp
+++ b/bh_tree_mpi/datastructures/Body.cpp
 #include "Body.hpp"
 #include <stdlib.h>
 #include <iostream>
+#include <cmath>
+#include <cfloat>

 namespace nbody {
 	using namespace std;
@@ -112,6 +114,30 @@ namespace nbody {
 		}
 	}

+	void Body::accumulateForce(Body from) {
+		double distance2 = 0.0;
+
+		distance2 += (this->position[0] - from.position[0]) * (this->position[0] - from.position[0]);
+		distance2 += (this->position[1] - from.position[1]) * (this->position[1] - from.position[1]);
+		distance2 += (this->position[2] - from.position[2]) * (this->position[2] - from.position[2]);
+		if (fabs(distance2) < FLT_EPSILON) {
+			distance2 = FLT_EPSILON;
+		}
+		double distance = sqrt(distance2);
+		double mdist = -1.0 * ((this->weight * from.weight) / distance2);
+		for (int i = 0; i < 3; i++) {
+			double vec = (this->position[i] - from.position[i]) / distance;
+
+			this->acceleration += vec * mdist;
+		}
+	}
+
+	void Body::resetAcceleration() {
+		for (int i = 0; i < 3; i++) {
+			this->acceleration[i] = 0.0;
+		}
+	}
+
 	double Body::getPosition(int index) {
 		return this->position[index];
 	}

--- a/bh_tree_mpi/datastructures/Body.hpp
+++ b/bh_tree_mpi/datastructures/Body.hpp
@@ -25,7 +25,9 @@ namespace nbody {
 		virtual double getMass();
 		virtual void setPosition(int index, double value);
 		virtual void setMass(double value);
+		virtual void resetAcceleration();
 		virtual void integrate();
+		virtual void accumulateForce(Body from);
 		virtual void print();
 	};
 }

--- a/bh_tree_mpi/datastructures/Tree.cpp
+++ b/bh_tree_mpi/datastructures/Tree.cpp
@@ -51,6 +51,17 @@ namespace nbody {
 		return nodes;
 	}

+	void Tree::accumulateForceFor(Body& body) {
+		body.resetAcceleration();
+		for (Node* n = this->nodes->next; n != this->nodes; n = n->next) {
+			if (n->leaf) {
+				for (vector<Body>::iterator it = n->bodies.begin(); it != n->bodies.end(); it++) {
+					body.accumulateForce(*it);
+				}
+			}
+		}
+	}
+
 	vector<Body> Tree::dubinskiParse(string filename) {
 		vector<Body> result;
 		string line;

--- a/bh_tree_mpi/datastructures/Tree.hpp
+++ b/bh_tree_mpi/datastructures/Tree.hpp
@@ -25,6 +25,7 @@ namespace nbody {
 		virtual void build(vector<Body> bodies) = 0;
 		virtual int numberOfChildren() = 0;
 		virtual unsigned long numberOfNodes();
+		virtual void accumulateForceFor(Body& body);
 		virtual bool isCorrect();
 	};