.gitignore

@@ -112,4 +112,5 @@ fabric.properties
 .idea/caches/build_file_checksums.ser
 
 /run
-*.jl
+*.csv
+*.jl

DLASystem.cpp

@@ -10,7 +10,7 @@ using std::endl;
 // this function gets called every step,
 //   if there is an active particle then it gets moved,
 //   if not then add a particle
-void DLASystem::update() {
+void DLASystem::Update() {
     this->frame++;
 
     if (lastParticleIsActive == 1) {
@@ -23,22 +23,32 @@ void DLASystem::update() {
     }
 }
 
+void DLASystem::clearParticles() {
+    // delete particles and the particle list
+    for (size_t i = 0; i < this->particleList.size(); i++) {
+        delete particleList[i];
+    }
+    particleList.clear();
+}
+
 // set the value of a grid cell for a particular position
 // note the position has the initial particle at (0,0)
 // but this corresponds to the middle of the grid array ie grid[ halfGrid ][ halfGrid ]
-void DLASystem::setGrid(std::array<double, 2> pos, int val) {
-    *index_grid(pos) = val;
+void DLASystem::setGrid(double pos[], int val) {
+    int halfGrid = gridSize / 2;
+    grid[(int) (pos[0] + halfGrid)][(int) (pos[1] + halfGrid)] = val;
 }
 
 // read the grid cell for a given position
-int DLASystem::readGrid(std::array<double, 2> pos) {
-    return *index_grid(pos);
+int DLASystem::readGrid(double pos[]) {
+    int halfGrid = gridSize / 2;
+    return grid[(int) (pos[0] + halfGrid)][(int) (pos[1] + halfGrid)];
 }
 
 // add a particle to the system at a specific position
-void DLASystem::addParticle(std::array<double, 2> pos) {
+void DLASystem::addParticle(double pos[]) {
     // create a new particle
-    auto *p = new Particle(pos);
+    Particle *p = new Particle(pos);
     // push_back means "add this to the end of the list"
     particleList.push_back(p);
 
@@ -50,8 +60,10 @@ void DLASystem::addParticle(std::array<double, 2> pos) {
 // if we hit an occupied site then we do nothing except print a message
 // (this should never happen)
 void DLASystem::addParticleOnAddCircle() {
+    double pos[2];
     double theta = rgen.random01() * 2 * M_PI;
-    std::array<double, 2> pos{ceil(addCircle * cos(theta)), ceil(addCircle * sin(theta))};
+    pos[0] = ceil(addCircle * cos(theta));
+    pos[1] = ceil(addCircle * sin(theta));
     if (readGrid(pos) == 0) {
         addParticle(pos);
     } else {
@@ -62,7 +74,7 @@ void DLASystem::addParticleOnAddCircle() {
 // send back the position of a neighbour of a given grid cell
 // NOTE: there is no check that the neighbour is inside the grid,
 // this has to be done separately...
-void DLASystem::setPosNeighbour(std::array<double, 2> &setpos, const std::array<double, 2> pos, int val) {
+void DLASystem::setPosNeighbour(double setpos[], double pos[], int val) {
     switch (val) {
         case 0:
             setpos[0] = pos[0] + 1.0;
@@ -85,7 +97,7 @@ void DLASystem::setPosNeighbour(std::array<double, 2> &setpos, const std::array<
 
 // when we add a particle to the cluster, we should update the cluster radius
 // and the sizes of the addCircle and the killCircle
-void DLASystem::updateClusterRadius(std::array<double, 2> pos) {
+void DLASystem::updateClusterRadius(double pos[]) {
     double newRadius = distanceFromOrigin(pos);
     if (newRadius > clusterRadius) {
         clusterRadius = newRadius;
@@ -112,7 +124,7 @@ void DLASystem::updateClusterRadius(std::array<double, 2> pos) {
 // make a random move of the last particle in the particleList
 void DLASystem::moveLastParticle() {
     int direction = rgen.randomInt(4);  // pick a random number in the range 0-3, which direction do we hop?
-    std::array<double, 2> newpos{};
+    double newpos[2];
 
     Particle *lastP = particleList[this->particleList.size() - 1];
 
@@ -144,7 +156,7 @@ int DLASystem::checkStick() {
     int result = 0;
     // loop over neighbours
     for (int i = 0; i < 4; i++) {
-        std::array<double, 2> checkpos{};
+        double checkpos[2];
         setPosNeighbour(checkpos, lastP->pos, i);
         // if the neighbour is occupied...
         if (readGrid(checkpos) == 1)
@@ -157,7 +169,6 @@ int DLASystem::checkStick() {
 // constructor
 DLASystem::DLASystem(Config config)
         : stickProbability(config.stickProbability),
-          grid(gridSize * gridSize),
           csv_out(std::move(config.csv)),
           endNum(config.maxParticles),
           frame(0),
@@ -169,8 +180,21 @@ DLASystem::DLASystem(Config config)
     /*
      * Handle grid data structure.
      * */
+
+    grid = new int *[gridSize];
+    for (int i = 0; i < gridSize; i++) {
+        grid[i] = new int[gridSize];
+    }
+
+    // set the grid to zero
+    for (int i = 0; i < gridSize; i++) {
+        for (int j = 0; j < gridSize; j++) {
+            grid[i][j] = 0;
+        }
+    }
+
     // Add particle to the centre of the grid to start
-    std::array<double, 2> pos{0.0, 0.0};
+    double pos[] = {0.0, 0.0};
     addParticle(pos);
 
     // Make sure to include the central location in our csv.
@@ -189,7 +213,11 @@ DLASystem::DLASystem(Config config)
 // destructor
 DLASystem::~DLASystem() {
     // delete the particles
-    particleList.clear();
+    clearParticles();
+    // delete the grid
+    for (int i = 0; i < gridSize; i++)
+        delete[] grid[i];
+    delete[] grid;
 
     if (csv_out.is_open()) {
         csv_out.flush();

DLASystem.h

@@ -2,12 +2,12 @@
 
 #include <iostream>
 #include <fstream>
-#include <cstdio>
+#include <stdio.h>
 #include <vector>
 
 #define _USE_MATH_DEFINES
 
-#include <cmath>
+#include <math.h>
 #include <random>
 #include <string>
 #include <sstream>
@@ -21,7 +21,6 @@ public:
     double stickProbability;
     std::ofstream csv;
     int maxParticles;
-
     Config(int argc, char **argv);
 };
 
@@ -31,6 +30,9 @@ private:
     // list of particles
     std::vector<Particle *> particleList;
 
+    // delete particles and clear the particle list
+    void clearParticles();
+
     // size of cluster
     double clusterRadius;
     // these are related to the DLA algorithm
@@ -41,7 +43,7 @@ private:
 
     // size of grid
     static const int gridSize = 1600;
-    std::vector<int> grid;
+    int **grid;  // this will be a 2d array that stores whether each site is occupied
 
     // random number generator, class name is rnd, instance is rgen
     rnd rgen;
@@ -59,20 +61,12 @@ private:
 
     int frame;
 
-    int *index_grid(std::array<double, 2> pos) {
-        int halfGrid = gridSize / 2;
-        int i = (int) (pos[0] + halfGrid);
-        int j = (int) (pos[1] + halfGrid);
-
-        int ij = i * gridSize + j;
-        return &grid[ij];
-    }
 public:
     // these are public variables and functions
 
     // update the system: if there is an active particle then move it,
     // else create a new particle (on the adding circle)
-    void update();
+    void Update();
 
     // is the simulation running (1) or paused (0) ?
     bool running;
@@ -81,7 +75,7 @@ public:
     int lastParticleIsActive;
 
     // constructor
-    explicit DLASystem(Config config);
+    DLASystem(Config config);
 
     // destructor
     ~DLASystem();
@@ -94,15 +88,15 @@ public:
     void pauseRunning() { running = false; }
 
     // if pos is outside the cluster radius then set clusterRadius to be the distance to pos.
-    void updateClusterRadius(std::array<double, 2> pos);
+    void updateClusterRadius(double pos[]);
 
     // set and read grid entries associated with a given position
-    void setGrid(std::array<double, 2> pos, int val);
+    void setGrid(double pos[], int val);
 
-    int readGrid(std::array<double, 2> pos);
+    int readGrid(double pos[]);
 
     // return the distance of a given point from the origin
-    double distanceFromOrigin(std::array<double, 2> pos) {
+    double distanceFromOrigin(double pos[]) {
         return sqrt(pos[0] * pos[0] + pos[1] * pos[1]);
     }
 
@@ -112,14 +106,14 @@ public:
     void setParticleInactive() { lastParticleIsActive = 0; }
 
     // add a particle at pos
-    void addParticle(std::array<double, 2> pos);
+    void addParticle(double pos[]);
 
     // add a particle at a random point on the addCircle
     void addParticleOnAddCircle();
 
     // assign setpos to the position of a neighbour of pos
     // which neighbour we look at is determined by val (=0,1,2,3)
-    void setPosNeighbour(std::array<double, 2> &setpos, std::array<double, 2> pos, int val);
+    void setPosNeighbour(double setpos[], double pos[], int val);
 
     // this attempts to move the last particle in the List to a random neighbour
     // if the neighbour is occupied then nothing happens

Particle.h

@@ -1,14 +1,22 @@
 #pragma once
-#include <array>
 
 class Particle {
 public:
     static const int dim = 2;  // we are in two dimensions
-    std::array<double, dim> pos{};
+    double *pos;  // pointer to an array of size dim, to store the position
 
-    // constructor, with a specified initial pos
-    explicit Particle(std::array<double, dim> pos) {
-        this->pos[0] = pos[0];
-        this->pos[1] = pos[1];
+    // default constructor
+    Particle() {
+        pos = new double[dim];
     }
+
+    // constructor, with a specified initial position
+    Particle(double set_pos[]) {
+        pos = new double[dim];
+        for (int d = 0; d < dim; d++)
+            pos[d] = set_pos[d];
+    }
+
+    // destructor
+    ~Particle() { delete[] pos; }
 };

mainDLA.cpp

@@ -51,7 +51,7 @@ int main(int argc, char **argv) {
      * NOTE: We run at max speed as rendering is handled by a different engine so we don't need to care.
      * */
     while (sys->running) {
-        sys->update();
+        sys->Update();
     }
 
     return 0;