机器学习——感知器算法实现

本次也是用processing3.0+写的，其官方网站https://processing.org/，建议直接看reference的例子进行学习。

感知器算法用的是我们老师给的ppt，实现的是二维的感知器，为了方便看，实际上多维的也是一样的：

运行效果是：

为了试验方便，我这是用了点击取点，键盘按一下t，大小写均可，下一个点的就是正例，按一下f，大小写均可，下一个点就是负例。

按s是开始进行学习度为1的迭代。结束会直接出直线，按2会出学习率为2的直线，迭代次数会打在程序底下，值是2.

代码仅供参考，请勿抄袭。转载请注明出处。

//blog:http://www.cnblogs.com/SweetBeens/p/8176764.html
class Point{
  float x, y;
  int k;
  Point(float x1,float y1){
    x = x1; y = y1;
  }
}
int num = 500;
int len = 0;
float h=1;
float r=0;
Point [] points = new Point[num];
int irit = 1000;
float w1 = 0, w2 = 0, b = 0;
//false=-1,true=1
boolean type = true;
//if one point wrong,then ,you need another irretate
boolean flag = true;
//one irretate
void rewrite(){
  for(int i = 0; i < len; i++){
    //if points[i] wrong side
    float result=points[i].k*(points[i].x*w1+points[i].y*w2+b);
    if(result<=0){
      w1 = w1+h*points[i].k*points[i].x;
      w2 = w2+h*points[i].k*points[i].y;
      b = b + h * points[i].k*r*r ;
      print(b," ");
      //w1=w1/w2;
     // w2=1;
      //b=b/w2;
      flag=true;
    }
  }
  }
//calculate R,check out in ppt 
void R(){
  float max=0;
  for(int i=0;i<len;i++){
    if(abs(points[i].x)>max)
    max=abs(points[i].x);
    if(abs(points[i].y)>max)
    max=abs(points[i].y);
  }
  r=max;
  println("max ",max);
}
void mousePressed(){
  Point p = new Point(mouseX,mouseY);
  if(type){
  p.k = 1;
  fill(255);
  }
  else{
  p.k = -1;
  fill(0);
  }
  rect(mouseX,mouseY,5,5);
  points[len] = p;
  len++;
}
void keyPressed(){
  int i=0;
  float y1=0,y2=0;
  if(key == 'T' || key == 't')
  type = true;
  else if(key == 'F' || key == 'f')
  type = false;
  else if(key == 's' || key == 'S')
  {
    
    R();
    while(i<irit&&flag==true){
      i++;
    flag=false;
    rewrite();
  //  println("w",w1," ",w2,"b",b);
     y1 = -b/w2;
    y2 = (-b-w1*width) / w2;
    //line(0,10,width,480);
   
    }
    println(y1," ",y2);
    println("w1,w2,b "+w1,w2,b);
     line(0,y1,width,y2);
  }
  else if(key == '2'){
    h = 0.2;
    w1 = 0;
    w2 = 0;
    b = 0;
    flag=true;
    i=0;
    while(i<irit&&flag==true){
      i++;
    flag=false;
    rewrite();
  //  println("w",w1," ",w2,"b",b);
     y1 = -b/w2;
    y2 = (-b-w1*width) / w2;
    //line(0,10,width,480);
   
    }
    println(y1," ",y2);
    println("w1,w2,b "+w1,w2,b);
     line(0,y1,width,y2);
  
  }
  println("i ",i);
}
void setup(){
  size(500,500);
  background(255);
}
void draw(){
}