Python 流浪星-codeabbey任务

Python 流浪星-codeabbey任务,python,algorithm,vector,puzzle,Python,Algorithm,Vector,Puzzle,我正在努力解决这个问题,但我不知道下一步该怎么办 问题陈述: 假设已经完成了一些初步的图像预处理,并且在两张图片上有恒星坐标形式的数据。这些图片约为100x100毫米,坐标也以毫米为单位,相对于它们的中心。请看下面的示意图: 你可以看到,在这两张照片中,恒星都显示在大致的圆形区域(可以把它看作是我们望远镜的外观),你可以发现它们代表着同一片天空——略微旋转和移动 您还可以看到其中一颗星星(用红色箭头标记)改变了相对于其他星星的位置 你的任务是找出这样一颗“游荡的恒星”,因为它很可能是彗星或小行

我正在努力解决这个问题,但我不知道下一步该怎么办


问题陈述:
假设已经完成了一些初步的图像预处理,并且在两张图片上有恒星坐标形式的数据。这些图片约为100x100毫米,坐标也以毫米为单位,相对于它们的中心。请看下面的示意图: 你可以看到,在这两张照片中,恒星都显示在大致的圆形区域(可以把它看作是我们望远镜的外观),你可以发现它们代表着同一片天空——略微旋转和移动

您还可以看到其中一颗星星(用红色箭头标记)改变了相对于其他星星的位置

你的任务是找出这样一颗“游荡的恒星”,因为它很可能是彗星或小行星

请注意,一些靠近边缘的恒星可能会从其中一张图片中消失(由于偏移),但“游荡恒星”离中心不远,因此在两张图片上都会出现

输入数据包含对应于两个图像的两个部分。 每个序列都以一个整数开始,即列出的星星数。 然后恒星的坐标(X和Y)随之变化

答案应在第一节和第二节分别给出游荡星的两个指数(基于0)

示例与上面的图片相同。第一部分坐标为(-18.2,11.1)的星29与第二部分坐标为(-19.7,6.9)的星3相同。 输入数据示例:
94#第1节包含94颗星
-47.5-10.4
19.1 25.9
18.9-10.4
-2.1-47.6


92#第2节包含92颗星
-14.8 10.9
18.8-0.1
-11.3.5.7
-19.7.6.9
-11.5-16.7
-45.4-15.3
6.0-46.9
-24.1-26.3
30.2 27.4

...

我面临的问题
问题是向量不匹配,甚至大小也不相同。例如,第一节中的第一个向量与第二节中的第一个向量不匹配,所以我无法基于此计算旋转矩阵。我还尝试根据每个截面的质心计算它,但边缘上的一些点可能不存在,因此它们将具有不同的质心(我尝试只包括长度小于40的向量,大小仍然不匹配)

所以我的问题是我的计算应该基于什么?如何找到一些匹配向量,以便计算它们的旋转矩阵?我需要往正确的方向推

我所做的是实现函数来找到两个给定向量之间的旋转矩阵。我使用的公式:
变换的_向量=R*原始_向量+t
其中R是旋转矩阵,因为向量也沿轴移动了一点,所以我还要加上t
现在我只需要两个向量来计算

编辑:我可能应该提到,我实际上得到了两个向量数组,每个图像一个,我实际上没有得到图像。我需要找到根据这些向量移动的恒星


谢谢

[edit2]完成重新编辑

我已经为此找到了一些时间/心情,使其更加健壮

  • xy0[],xy1[]
    作为输入星列表
  • max\u r
    成为附近的搜索区域treshld
  • max_err
    设为最大可接受的群集匹配错误
下面是算法:

  • 按x asc对xy0[]排序
    • 这使得搜索更快更容易
  • xy0[]中查找星团
    
    • 环游全明星
    • 并将它们与附近的恒星进行对照
    • 由于排序的原因,附近的星星也将接近当前的星星索引
    • 所以只需搜索阵列中这颗星前后的近距离区域
    • 直到x距离穿过
      max\u r
    • 将集群添加到
      cl0[]
      集群列表(如果找到)
    • (星团由两颗或更多近距离恒星组成)
    • 在添加新群集之前
    • 检查附近是否没有群集
    • 如果离另一个集群太近,则合并
  • 完全重新计算找到的群集
    • 平均坐标
    • 内部所有恒星之间的距离
    • 按距离asc对它们进行排序
  • 做1,2,3。同样适用于
    xy1[],cl1[]
  • 查找群集之间的匹配项
    • 因此,检查内部的距离列表是否相同
    • (记住abs误差的最小和)
    • 如果错误大于最大错误,则拒绝此群集匹配
    • 这是一种强匹配,我们在许多集群(大max_r)上进行了测试,但没有在此数据集上出现不匹配
  • cl0[]
    中找到的已找到匹配项的群集中选取2个群集
  • 以匹配的簇为例
  • 从这4个点计算
    xy0[],xy1[]之间的转换
    
    • 我使用了集群的平均坐标,它非常匹配
  • 这是视觉效果:

    • 左侧是
      xy0[]
      set
    • 中间是
      xy1[]
      set
    • 在右边,蓝色的大点是
      xy0[]
    • 绿色的小点被变换
      xy1[]
    • 这些数字是群集匹配的错误(-1表示未找到匹配项)
    [notes]

    我使用自己的
    列表
    模板

    • 它只是动态地重新分配线性阵列
    • 列表x
      intx[]相同
    • 其中
      x[i]
      是项目访问
    • x.num
      是数组中的项数
    • x.add(5)
      x[x.num]=5相同;x、 num++
    从这一点上哟
    //---------------------------------------------------------------------------
    // answer: 29 3
    // input data:
    const int n0=94; double xy0[n0][2]=
        {
        -47.5,-10.4,19.1,25.9,18.9,-10.4,-2.1,-47.6,41.8,-12.1,-15.7,12.1,-11.0,-0.6,
        -15.6,-7.6,14.9,43.5,16.6,0.1,3.6,-33.5,-14.2,20.8,17.8,-29.8,-2.2,-12.8,
        44.6,19.7,17.9,-41.3,24.6,37.0,43.9,14.5,23.8,19.6,-4.2,-40.5,32.0,17.2,
        22.6,-26.9,9.9,-33.4,-13.6,6.6,48.5,-3.5,-9.9,-39.9,-28.2,20.7,7.1,15.5,
        -36.2,-29.9,-18.2,11.1,-1.2,-13.7,9.3,9.3,39.2,15.8,-5.2,-16.2,-34.9,5.0,
        -13.4,-31.8,24.7,-29.1,1.4,24.0,-24.4,18.0,11.9,-29.1,36.3,18.6,30.3,38.4,
        4.8,-20.5,-46.8,12.1,-44.2,-6.0,-1.4,-39.7,-1.0,-13.7,13.3,23.6,37.4,-7.0,
        -22.3,37.8,17.6,-3.3,35.0,-9.1,-44.5,13.1,-5.1,19.7,-12.1,1.7,-30.9,-1.9,
        -19.4,-15.0,10.8,31.9,19.7,3.1,29.9,-16.6,31.7,-26.8,38.1,30.2,3.5,25.1,
        -14.8,19.6,2.1,29.0,-9.6,-32.9,24.8,4.9,-2.2,-24.7,-4.3,-37.4,-3.0,37.4,
        -34.0,-21.2,-18.4,34.6,9.3,-45.2,-21.1,-10.3,-19.8,29.1,31.3,37.7,27.2,19.3,
        -1.6,-45.6,35.3,-23.5,-39.9,-19.8,-3.8,40.6,-15.7,12.5,-0.8,-16.3,-5.1,13.1,
        -13.8,-25.7,43.8,5.6,9.2,38.6,42.2,0.2,-10.0,-48.6,14.1,-6.5,34.6,-26.8,
        11.1,-6.7,-6.1,25.1,-38.3,8.1,
        };
    const int n1=92; double xy1[n1][2]=
        {
        -14.8,10.9,18.8,-0.1,-11.3,5.7,-19.7,6.9,-11.5,-16.7,-45.4,-15.3,6.0,-46.9,
        -24.1,-26.3,30.2,27.4,21.4,-27.2,12.1,-36.1,23.8,-38.7,41.5,5.3,-8.7,25.5,
        36.6,-5.9,43.7,-14.6,-9.7,-8.6,34.7,-19.3,-15.5,19.3,21.4,3.9,34.0,29.8,
        6.5,19.5,28.2,-21.7,13.4,-41.8,-25.9,-6.9,37.5,27.8,18.1,44.7,-43.0,-19.9,
        -15.7,18.0,2.4,-31.6,9.6,-37.6,15.4,-28.8,43.6,-11.2,4.6,-10.2,-8.8,38.2,
        8.7,-34.6,-4.7,14.1,-1.7,31.3,0.6,27.9,26.3,13.7,-1.2,26.3,32.1,-17.7,
        15.5,32.6,-14.4,-12.6,22.3,-22.5,7.0,48.5,-6.4,20.5,-42.9,4.2,-23.0,31.6,
        -24.6,14.0,-30.2,-26.5,-29.0,15.7,6.0,36.3,44.3,13.5,-27.6,33.7,13.4,-43.9,
        10.5,28.9,47.0,1.4,10.2,14.0,13.3,-15.9,-3.4,-25.6,-14.7,10.5,21.6,27.6,
        21.8,10.6,-37.8,-14.2,7.6,-21.8,-8.6,1.3,6.8,-13.3,40.9,-15.3,-10.3,41.1,
        6.0,-10.8,-1.5,-31.4,-35.6,1.0,2.5,-14.3,24.4,-2.6,-24.1,-35.3,-29.9,-34.7,
        15.9,-1.0,19.5,7.0,44.5,19.1,39.7,2.7,2.7,42.4,-23.0,25.9,25.0,28.2,31.2,-32.8,
        3.9,-38.4,-44.8,2.7,-39.9,-19.3,-7.0,-0.6,5.8,-10.9,-44.5,19.9,-31.5,-1.2,
        };
    //---------------------------------------------------------------------------
    struct _dist                        // distance structure
        {
        int ix;                         // star index
        double d;                       // distance to it
        _dist(){}; _dist(_dist& a){ *this=a; }; ~_dist(){}; _dist* operator = (const _dist *a) { *this=*a; return this; }; /*_dist* operator = (const _dist &a) { ...copy... return this; };*/
        };
    struct _cluster                     // star cluster structure
        {
        double x,y;                     // avg coordinate
        int iy;                         // ix of cluster match in the other set or -1
        double err;                     // error of cluster match
        List<int> ix;                   // star ix
        List<double> d;                 // distances of stars ix[] against each other
        _cluster(){}; _cluster(_cluster& a){ *this=a; }; ~_cluster(){}; _cluster* operator = (const _cluster *a) { *this=*a; return this; }; /*_cluster* operator = (const _cluster &a) { ...copy... return this; };*/
        };
    const double max_r=5.0;             // find cluster max radius
    const double max_err=0.2;           // match cluster max distance error treshold
    const double max_rr=max_r*max_r;
    const double max_errr=max_err*max_err;
    int wi0,wi1;                        // result wandering star ix ...
    int ix0[n0],ix1[n1];                // original star indexes
    List<_cluster> cl0,cl1;             // found clusters
    
    double txy1[n1][2];                 // transformed xy1[]
    //---------------------------------------------------------------------------
    double atanxy(double x,double y)
        {
        const double pi=M_PI;
        const double pi2=2.0*M_PI;
        int sx,sy;
        double a;
        const double _zero=1.0e-30;
        sx=0; if (x<-_zero) sx=-1; if (x>+_zero) sx=+1;
        sy=0; if (y<-_zero) sy=-1; if (y>+_zero) sy=+1;
        if ((sy==0)&&(sx==0)) return 0;
        if ((sx==0)&&(sy> 0)) return 0.5*pi;
        if ((sx==0)&&(sy< 0)) return 1.5*pi;
        if ((sy==0)&&(sx> 0)) return 0;
        if ((sy==0)&&(sx< 0)) return pi;
        a=y/x; if (a<0) a=-a;
        a=atan(a);
        if ((x>0)&&(y>0)) a=a;
        if ((x<0)&&(y>0)) a=pi-a;
        if ((x<0)&&(y<0)) a=pi+a;
        if ((x>0)&&(y<0)) a=pi2-a;
        return a;
        }
    //---------------------------------------------------------------------------
    void compute()
        {
        int i0,i1,e,f;
        double a,x,y;
        // original indexes (to keep track)
        for (e=0;e<n0;e++) ix0[e]=e;
        for (e=0;e<n1;e++) ix1[e]=e;
        // sort xy0[] by x asc
        for (e=1;e;) for (e=0,i0=0,i1=1;i1<n0;i0++,i1++)
         if (xy0[i0][0]>xy0[i1][0])
            {
            e=ix0[i0]   ; ix0[i0]   =ix0[i1]   ; ix0[i1]   =e; e=1;
            a=xy0[i0][0]; xy0[i0][0]=xy0[i1][0]; xy0[i1][0]=a;
            a=xy0[i0][1]; xy0[i0][1]=xy0[i1][1]; xy0[i1][1]=a;
            }
        // sort xy1[] by x asc
        for (e=1;e;) for (e=0,i0=0,i1=1;i1<n1;i0++,i1++)
         if (xy1[i0][0]>xy1[i1][0])
            {
            e=ix1[i0]   ; ix1[i0]   =ix1[i1]   ; ix1[i1]   =e; e=1;
            a=xy1[i0][0]; xy1[i0][0]=xy1[i1][0]; xy1[i1][0]=a;
            a=xy1[i0][1]; xy1[i0][1]=xy1[i1][1]; xy1[i1][1]=a;
            }
        _dist d;
        _cluster c,*pc,*pd;
        List<_dist> dist;
        // find star clusters in xy0[]
        for (cl0.num=0,i0=0;i0<n0;i0++)
            {
            for (dist.num=0,i1=i0+1;(i1<n0)&&(fabs(xy0[i0][0]-xy0[i1][0])<=max_r);i1++) // stars nearby
                {
                x=xy0[i0][0]-xy0[i1][0]; x*=x;
                y=xy0[i0][1]-xy0[i1][1]; y*=y; a=x+y;
                if (a<=max_rr) { d.ix=i1; d.d=a; dist.add(d); }
                }
            if (dist.num>=2)                                                            // add/compute cluster if found
                {
                c.ix.num=0; c.err=-1.0;
                c.ix.add(i0);   for (i1=0;i1<dist.num;i1++) c.ix.add(dist[i1].ix); c.iy=-1;
                c.x=xy0[i0][0]; for (i1=0;i1<dist.num;i1++) c.x+=xy0[dist[i1].ix][0]; c.x/=dist.num+1;
                c.y=xy0[i0][1]; for (i1=0;i1<dist.num;i1++) c.y+=xy0[dist[i1].ix][1]; c.y/=dist.num+1;
                for (e=1,i1=0;i1<cl0.num;i1++)
                    {
                    pc=&cl0[i1];
                    x=c.x-pc->x; x*=x;
                    y=c.y-pc->y; y*=y; a=x+y;
                    if (a<max_rr)   // merge if too close to another cluster
                        {
                        pc->x=0.5*(pc->x+c.x);
                        pc->y=0.5*(pc->y+c.y);
                        for (e=0;e<c.ix.num;e++)
                            {
                            for (f=0;f<pc->ix.num;f++)
                             if (pc->ix[f]==c.ix[e]) { f=-1; break; }
                            if (f>=0) pc->ix.add(c.ix[e]);
                            }
                        e=0; break;
                        }
                    }
                if (e) cl0.add(c);
                }
            }
        // full recompute clusters
        for (f=0,pc=&cl0[f];f<cl0.num;f++,pc++)
            {
            // avg coordinate
            pc->x=0.0;  for (i1=0;i1<pc->ix.num;i1++) pc->x+=xy0[pc->ix[i1]][0]; pc->x/=pc->ix.num;
            pc->y=0.0;  for (i1=0;i1<pc->ix.num;i1++) pc->y+=xy0[pc->ix[i1]][1]; pc->y/=pc->ix.num;
            // distances
            for (pc->d.num=0,i0=   0;i0<pc->ix.num;i0++)
            for (            i1=i0+1;i1<pc->ix.num;i1++)
                {
                x=xy0[pc->ix[i1]][0]-xy0[pc->ix[i0]][0]; x*=x;
                y=xy0[pc->ix[i1]][1]-xy0[pc->ix[i0]][1]; y*=y;
                pc->d.add(sqrt(x+y));
                }
            // sort by distance asc
            for (e=1;e;) for (e=0,i0=0,i1=1;i1<pc->d.num;i0++,i1++)
             if (pc->d[i0]>pc->d[i1])
                {
                a=pc->d[i0]; pc->d[i0]=pc->d[i1]; pc->d[i1]=a; e=1;
                }
            }
    
        // find star clusters in xy1[]
        for (cl1.num=0,i0=0;i0<n1;i0++)
            {
            for (dist.num=0,i1=i0+1;(i1<n1)&&(fabs(xy1[i0][0]-xy1[i1][0])<=max_r);i1++) // stars nearby
                {
                x=xy1[i0][0]-xy1[i1][0]; x*=x;
                y=xy1[i0][1]-xy1[i1][1]; y*=y; a=x+y;
                if (a<=max_rr) { d.ix=i1; d.d=a; dist.add(d); }
                }
            if (dist.num>=2)                                                            // add/compute cluster if found
                {
                c.ix.num=0; c.err=-1.0;
                c.ix.add(i0);   for (i1=0;i1<dist.num;i1++) c.ix.add(dist[i1].ix); c.iy=-1;
                c.x=xy1[i0][0]; for (i1=0;i1<dist.num;i1++) c.x+=xy1[dist[i1].ix][0]; c.x/=dist.num+1;
                c.y=xy1[i0][1]; for (i1=0;i1<dist.num;i1++) c.y+=xy1[dist[i1].ix][1]; c.y/=dist.num+1;
                for (e=1,i1=0;i1<cl1.num;i1++)
                    {
                    pc=&cl1[i1];
                    x=c.x-pc->x; x*=x;
                    y=c.y-pc->y; y*=y; a=x+y;
                    if (a<max_rr)   // merge if too close to another cluster
                        {
                        pc->x=0.5*(pc->x+c.x);
                        pc->y=0.5*(pc->y+c.y);
                        for (e=0;e<c.ix.num;e++)
                            {
                            for (f=0;f<pc->ix.num;f++)
                             if (pc->ix[f]==c.ix[e]) { f=-1; break; }
                            if (f>=0) pc->ix.add(c.ix[e]);
                            }
                        e=0; break;
                        }
                    }
                if (e) cl1.add(c);
                }
            }
        // full recompute clusters
        for (f=0,pc=&cl1[f];f<cl1.num;f++,pc++)
            {
            // avg coordinate
            pc->x=0.0;  for (i1=0;i1<pc->ix.num;i1++) pc->x+=xy1[pc->ix[i1]][0]; pc->x/=pc->ix.num;
            pc->y=0.0;  for (i1=0;i1<pc->ix.num;i1++) pc->y+=xy1[pc->ix[i1]][1]; pc->y/=pc->ix.num;
            // distances
            for (pc->d.num=0,i0=   0;i0<pc->ix.num;i0++)
            for (            i1=i0+1;i1<pc->ix.num;i1++)
                {
                x=xy1[pc->ix[i1]][0]-xy1[pc->ix[i0]][0]; x*=x;
                y=xy1[pc->ix[i1]][1]-xy1[pc->ix[i0]][1]; y*=y;
                pc->d.add(sqrt(x+y));
                }
            // sort by distance asc
            for (e=1;e;) for (e=0,i0=0,i1=1;i1<pc->d.num;i0++,i1++)
             if (pc->d[i0]>pc->d[i1])
                {
                a=pc->d[i0]; pc->d[i0]=pc->d[i1]; pc->d[i1]=a; e=1;
                }
            }
        // find matches
        for (i0=0,pc=&cl0[i0];i0<cl0.num;i0++,pc++) if  (pc->iy<0){ e=-1; x=0.0;
        for (i1=0,pd=&cl1[i1];i1<cl1.num;i1++,pd++) if (pc->d.num==pd->d.num)
                {
                for (y=0.0,f=0;f<pc->d.num;f++) y+=fabs(pc->d[f]-pd->d[f]);
                if ((e<0)||(x>y)) { e=i1; x=y; }
                }
            x/=pc->d.num;
            if ((e>=0)&&(x<max_err))
                {
                if (cl1[e].iy>=0) cl0[cl1[e].iy].iy=-1;
                pc->iy =e; cl1[e].iy=i0;
                pc->err=x; cl1[e].err=x;
                }
            }
        // compute transform
        double tx0,tx1,ty0,ty1,tc,ts;
        tx0=0.0; tx1=0.0; ty0=0.0; ty1=0.0; tc=1.0; ts=0.0; i0=-1; i1=-1;
        for (e=0,f=0,pc=&cl0[e];e<cl0.num;e++,pc++) if (pc->iy>=0)  // find 2 clusters with match
            {
            if (f==0)   i0=e;
            if (f==1) { i1=e; break; }
            f++;
            }
        if (i1>=0)
            {
            pc=&cl0[i0];        // translation and offset from xy0 set
            pd=&cl0[i1];
            tx1=pc->x;
            ty1=pc->y;
            a =atanxy(pd->x-pc->x,pd->y-pc->y);
            pc=&cl1[pc->iy];    // translation and offset from xy1 set
            pd=&cl1[pd->iy];
            tx0=pc->x;
            ty0=pc->y;
            a-=atanxy(pd->x-pc->x,pd->y-pc->y);
            tc=cos(a);
            ts=sin(a);
            }
        // transform xy1 -> txy1 (in xy0 coordinate system)
        for (i1=0;i1<n1;i1++)
            {
            x=xy1[i1][0]-tx0;
            y=xy1[i1][1]-ty0;
            txy1[i1][0]=x*tc-y*ts+tx1;
            txy1[i1][1]=x*ts+y*tc+ty1;
            }
        // sort txy1[] by x asc (after transfrm)
        for (e=1;e;) for (e=0,i0=0,i1=1;i1<n1;i0++,i1++)
         if (txy1[i0][0]>txy1[i1][0])
            {
            e= ix1[i0]   ;  ix1[i0]   = ix1[i1]   ;  ix1[i1]   =e; e=1;
            a=txy1[i0][0]; txy1[i0][0]=txy1[i1][0]; txy1[i1][0]=a;
            a=txy1[i0][1]; txy1[i0][1]=txy1[i1][1]; txy1[i1][1]=a;
            }
        // find match between xy0,txy1 (this can be speeded up by exploiting sorted order)
        int ix01[n0],ix10[n1];
        for (i0=0;i0<n0;i0++) ix01[i0]=-1;
        for (i1=0;i1<n1;i1++) ix10[i1]=-1;
        for (i0=0;i0<n0;i0++){ a=-1.0;
        for (i1=0;i1<n1;i1++)
            {
            x=xy0[i0][0]-txy1[i1][0]; x*=x;
            y=xy0[i0][1]-txy1[i1][1]; y*=y; x+=y;
            if (x<max_errr)
             if ((a<0.0)||(a>x)) { a=x; ix01[i0]=i1; ix10[i1]=i0; }
            }}
        // find the closest stars from unmatched stars
        a=-1.0; wi0=-1; wi1=-1;
        for (i0=0;i0<n0;i0++) if (ix01[i0]<0)
        for (i1=0;i1<n1;i1++) if (ix10[i1]<0)
            {
            x=xy0[i0][0]-txy1[i1][0]; x*=x;
            y=xy0[i0][1]-txy1[i1][1]; y*=y; x+=y;
            if ((wi0<0)||(a>x)) { a=x; wi0=i0; wi1=i1; }
            }
        }
    //---------------------------------------------------------------------------
    void draw()
        {
        bmp->Canvas->Font->Charset=OEM_CHARSET;
        bmp->Canvas->Font->Name="System";
        bmp->Canvas->Font->Pitch=fpFixed;
        bmp->Canvas->Font->Color=0x00FFFF00;
        bmp->Canvas->Brush->Color=0x00000000;
        bmp->Canvas->FillRect(TRect(0,0,xs,ys));
        _cluster *pc;
        int i,x0,y0,x1,y1,x2,y2,xx,yy,r,_r=4;
        double x,y,m;
        x0=xs/6; x1=3*x0; x2=5*x0;
        y0=ys/2; y1=  y0; y2=  y0;
        x=x0/60.0; y=y0/60.0; if (x<y) m=x; else m=y;
        // clusters match
        bmp->Canvas->Pen  ->Color=clAqua;
        bmp->Canvas->Brush->Color=0x00303030;
        for (i=0,pc=&cl0[i];i<cl0.num;i++,pc++)
         if (pc->iy>=0)
            {
            x=pc->x*m; xx=x0+x;
            y=pc->y*m; yy=y0-y;
            bmp->Canvas->MoveTo(xx,yy);
            x=cl1[pc->iy].x*m; xx=x1+x;
            y=cl1[pc->iy].y*m; yy=y1-y;
            bmp->Canvas->LineTo(xx,yy);
            }
        // clusters area
        for (i=0,pc=&cl0[i];i<cl0.num;i++,pc++)
            {
            x=pc->x*m; xx=x0+x;
            y=pc->y*m; yy=y0-y;
            r=pc->d[pc->d.num-1]*m*0.5+_r;
            bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
            bmp->Canvas->TextOutA(xx+r,yy+r,AnsiString().sprintf("%.3lf",pc->err));
            }
        for (i=0,pc=&cl1[i];i<cl1.num;i++,pc++)
            {
            x=pc->x*m; xx=x1+x;
            y=pc->y*m; yy=y1-y;
            r=pc->d[pc->d.num-1]*m*0.5+_r;
            bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
            bmp->Canvas->TextOutA(xx+r,yy+r,AnsiString().sprintf("%.3lf",pc->err));
            }
        // stars
        r=_r;
        bmp->Canvas->Pen  ->Color=clAqua;
        bmp->Canvas->Brush->Color=clBlue;
        for (i=0;i<n0;i++)
            {
            x=xy0[i][0]*m; xx=x0+x;
            y=xy0[i][1]*m; yy=y0-y;
            bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
            }
        for (i=0;i<n1;i++)
            {
            x=xy1[i][0]*m; xx=x1+x;
            y=xy1[i][1]*m; yy=y1-y;
            bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
            }
        // merged sets
        r=_r;
        bmp->Canvas->Pen  ->Color=clBlue;
        bmp->Canvas->Brush->Color=clBlue;
        for (i=0;i<n0;i++)
            {
            x=xy0[i][0]*m; xx=x2+x;
            y=xy0[i][1]*m; yy=y2-y;
            bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
            }
        r=_r-2;
        bmp->Canvas->Pen  ->Color=clGreen;
        bmp->Canvas->Brush->Color=clGreen;
        for (i=0;i<n1;i++)
            {
            x=txy1[i][0]*m; xx=x2+x;
            y=txy1[i][1]*m; yy=y2-y;
            bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
            }
        // wandering star
        r=_r+5;
        bmp->Canvas->Pen  ->Color=0x00FF8000;
        bmp->Canvas->Font ->Color=0x00FF8000;
        bmp->Canvas->Brush->Style=bsClear;
        x=xy0[wi0][0]*m; xx=x2+x;
        y=xy0[wi0][1]*m; yy=y2-y;
        bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
        bmp->Canvas->TextOutA(xx+r,yy+r,ix0[wi0]);
    
        bmp->Canvas->Pen  ->Color=0x0040FF40;
        bmp->Canvas->Font ->Color=0x0040FF40;
        x=txy1[wi1][0]*m; xx=x2+x;
        y=txy1[wi1][1]*m; yy=y2-y;
        bmp->Canvas->Ellipse(xx-r,yy-r,xx+r,yy+r);
        bmp->Canvas->TextOutA(xx+r,yy+r,ix1[wi1]);
        bmp->Canvas->Brush->Style=bsSolid;
    
        Form1->Canvas->Draw(0,0,bmp);
        }
    //---------------------------------------------------------------------------
    
    X        10          20   30   40
    matches    \        /            \
    Y           11    18              41   50
    cost         1     4      20       1   20      Total cost: 46
    
    X        10   20   30   40
    matches   |    |    |    |
    Y        11   18   41   50
    cost      1    4  121  100                     Total cost: 226