在我的班上，我们的任务如下：
对于此作业，您将尝试制作一个程序来计算一组形状的重叠区域，实现蒙特卡洛积分，如课堂上所讨论的。 创建AreaEstimator.java，这是一个使用随机估计估计任意数量的圆和三角形的重叠区域的程序。程序的参数将是在此试验中使用的随机生成点的数量，后面是定义形状的点的坐标。例如，
java AreaEstimator 1000000 circle 2.0 2.0 1.0 triangle 1.0 1.0 2.5 3.0 2.0 -3.0 circle 2.5 1.0 3.0
将产生一百万个随机点来估计顶点为（1.0,1.0），（2.5,3.0），（2.0，-3.0）的三角形的重叠，其中两个圆的中心位于（2.0,2.0）和（2.5,1.0），其半径分别为1.0和3.0。
以下是Circle类的代码：
public class Circle {
private double xcenter;
private double ycenter;
private double radius;
private double xcmax;
private double xcmin;
private double ycmax;
private double ycmin;
public Circle ( double xcenter, double ycenter, double radius){
if(radius <= 0){
throw new IllegalArgumentException();
}
this.xcenter = xcenter;
this.ycenter = ycenter;
this.radius = radius;
}
public void maxAndMinCircle (){ //find the minimun and maximum for the plane according to this circle
xcmax = (this.xcenter + this.radius);
ycmax = (this.ycenter + this.radius);
xcmin = (this.xcenter - this.radius);
ycmin = (this.ycenter - this.radius);
}
public double getXCMax (){
return xcmax;
}
public double getYCMax () {
return ycmax;
}
public double getXCMin() {
return xcmin;
}
public double getYCMin(){
return ycmin;
}
public boolean outsideCircle(double randX, double randY){ // find if the random point passed thru is in this circle
double distance = Math.sqrt((randX-this.xcenter)*(randX-this.xcenter) + (randY-this.ycenter) * (randY - this.ycenter));
return distance >= radius;
}}
三角班：
public class Triangle {
private double cornerx1;
private double cornery1;
private double cornerx2;
private double cornery2;
private double cornerx3;
private double cornery3;
private double xtmax;
private double xtmin;
private double ytmax;
private double ytmin;
private Double[] corners;
public Triangle (double cornerx1, double cornery1, double cornerx2, double cornery2, double cornerx3, double cornery3){
corners = new Double [6];
corners[0] = cornerx1;
corners[1] = cornery1;
corners[2] = cornerx2;
corners[3] = cornery2;
corners[4] = cornerx3;
corners[5] = cornery3;
}
public void maxAndMinTriangle (){ // find the minimum and maximum of the plane according to this triangle
xtmax = corners[0];
for(int i=1;i < corners.length;i += 2){
if(corners[i] > xtmax){
xtmax = corners[i];
}
}
xtmin = corners[0];
for(int i=1;i < corners.length;i += 2){
if(corners[i] < xtmin){
xtmin = corners[i];
}
}
ytmax = corners[1];
for(int i=1;i < corners.length;i += 2){
if(corners[i] > ytmax){
ytmax = corners[i];
}
}
ytmin = corners[1];
for(int i=1;i < corners.length;i += 2){
if(corners[i] < ytmin){
ytmin = corners[i];
}
}
}
public double getXTMax (){
return xtmax;
}
public double getYTMax () {
return ytmax;
}
public double getXTMin() {
return xtmin;
}
public double getYTMin(){
return ytmin;
}
//public static boolean isLeft (double x1, double y1, double x2, double y2, double x3, double y3){
//return ( 0 <= ( ( x2 - x1 ) * ( y - y1) )- (( y2 - y1) * ( x - x1)));
//}
public boolean isLeft1 (double randX, double randY){ // find if this point is to the left of the first line
return ( 0 <= ( ( corners[2] - corners[0] ) * ( randY - corners[1]) )- (( corners[3] - corners[1]) * ( randX - corners[0])));
}
public boolean isLeft2 (double randX, double randY){ // find if this point is to the left of the second line
return ( 0 <= ( ( corners[4] - corners[0]) * ( randY - corners[1]) )- (( corners[5] - corners[1]) * ( randX - corners[0])));
}
public boolean isLeft3 (double randX, double randY){ // find if this point is to the left of the third line
return ( 0 <= ( ( corners[4] - corners[2] ) * ( randY - corners[3]) )- (( corners[5] - corners[3]) * ( randX - corners[2])));
}
public boolean outsideTriangle ( double randX, double randY ){ // find if this point is inside of the triangle
int counter = 0;
if (isLeft1(randX,randY)){
counter++;
}
if (isLeft2(randX,randY)){
counter++;
}
if (isLeft3(randX,randY)){
counter++;
}
return counter == 2; // must be to the left of exactly 2 of the lines
}}
然后是AreaEstimator类：
public class AreaEstimator{
public static double[] maxAndMinValues (Circle[] circles,Triangle[] triangles){
// find maximum and minimum values according to all of the triangles and circles
double xmax = -100;
double ymax = -100;
double xmin = 100;
double ymin = 100;
for (int l=0; l < circles.length; l++){
if (xmax < circles[l].getXCMax()){
xmax = circles[l].getXCMax();
}
if (ymax < circles[l].getYCMax()){
ymax = circles[l].getYCMax();
}
if (xmin > circles[l].getXCMin()){
xmin = circles[l].getXCMin();
}
if (ymin > circles[l].getYCMin()){
ymin = circles[l].getYCMin();
}
}
for ( int m = 0; m < triangles.length; m++){
if(xmax < triangles[m].getXTMax()){
xmax = triangles[m].getXTMax();
}
if(ymax < triangles[m].getYTMax()){
ymax = triangles[m].getYTMax();
}
if(xmin > triangles[m].getXTMin()){
xmin = triangles[m].getXTMin();
}
if(ymin > triangles[m].getYTMin()){
ymin = triangles[m].getYTMin();
}
}
double[] result = new double [4];
result[0] = xmax;
result[1] = ymax;
result[2] = xmin;
result[3] = ymin;
return result;
}
public static void main (String[] args) {
double numThrows = Integer.parseInt(args[0]); // initialize amount of throws
if (numThrows <= 0){
throw new IllegalArgumentException();
}
int countCircles = 0; // find the amount of circles given
for ( int i = 1; i<args.length; i++){
if(args[i].equals("circle")){
countCircles++;
}
}
Circle[] circles = new Circle [countCircles];
for ( int i = 1; i<args.length; i++){
if (args[i].equals("circle")){
for ( int k = 0; k< countCircles; k++){
double xcenter = Double.parseDouble(args[i+1]);
double ycenter = Double.parseDouble(args[i+2]);
double radius = Double.parseDouble(args[i+3]);
circles[k] = new Circle (xcenter, ycenter, radius); //values associated with this circle
circles[k].maxAndMinCircle();//max and min value of the circle itself
}
}
}
int countTriangles = 0; // find the amount of the triangles given
for ( int i = 1; i < args.length; i++){
if(args[i].equals("triangle")){
countTriangles++;
}
}
Triangle[] triangles = new Triangle [countTriangles];
for ( int i = 1; i<args.length; i++){
if (args[i].equals("triangle")){
for ( int p = 0; p< countTriangles; p++){
double cornerx1 = Double.parseDouble(args[i+1]);
double cornery1 = Double.parseDouble(args[i+2]);
double cornerx2 = Double.parseDouble(args[i+3]);
double cornery2 = Double.parseDouble(args[i+4]);
double cornerx3 = Double.parseDouble(args[i+5]);
double cornery3 = Double.parseDouble(args[i+6]);
triangles[p] = new Triangle (cornerx1, cornery1, cornerx2, cornery2, cornerx3, cornery3);
//values associated with this triangle
triangles[p].maxAndMinTriangle(); //max and min value of the triangle itself
}
}
}
boolean dartsInOverlap = true;
double countInOverlap = 0; // initialize amount of darts in the overlapping shape
double[]result = maxAndMinValues(circles,triangles);
for(int i= 0;i < numThrows;i++){
double randX= (Math.random() * (result[0]-result[2]) + result[2]) ; // generate a random x value
double randY= (Math.random() * (result[1]-result[3])+ result[3]); // generate a random y value
for ( int h = 0; h < circles.length && dartsInOverlap; h++){
if (circles[h].outsideCircle(randX, randY)){
dartsInOverlap = false; // if the point is outside of the circle, it returns false
}
}
for ( int q = 0; q < triangles.length && dartsInOverlap; q++){
if (triangles[q].outsideTriangle(randX, randY)){
dartsInOverlap = false; // if the point is outside of the triangle, it returns false
}
}
if (dartsInOverlap){
countInOverlap++; // counts up the amount of points in the overlapping shape
}
dartsInOverlap = true;
}
System.out.println("This many darts were in the overlap between the shapes:" + countInOverlap);
// counts up the amount of points in the overlapping shape
System.out.println("The estimated overlapped areas is" + (result[0]-result[2])*(result[1]-result[3]) *(countInOverlap/numThrows));
//finds estimated area
}}
我的代码适用于一些测试用例，如果在命令行中只输入了一个圆圈和三角形，或者只有一个唯一的圆圈。三角形本身或任何其他组合将给出远离期望区域估计的答案。我查看并查看了我的代码，这看起来很合乎逻辑。那么，在我的代码中，问题仍然存在？任何帮助，将不胜感激。
答案 0 :(得分：0)
maxAndMinTriangle中至少有一个拼写错误。你写了 1 ，你需要 0
xtmax = corners[0];
for(int i=1;i < corners.length;i += 2){
...
xtmin = corners[0];
for(int i=1;i < corners.length;i += 2){
应该是
xtmax = corners[0];
for(int i=0;i < corners.length;i += 2){
...
xtmin = corners[0];
for(int i=0;i < corners.length;i += 2){