配置する

• だいたいN個の点を半径１の球面上に「ほぼ均一に配置する」
  • N=1000を指定して1513個の点がプロットされた・・・(これが誤差)
• Javaで３次元座標として出力する

public static void main(String[] args)throws IOException {
int N=1000;
new SphereCoords sc = new SphereCoords(N);
SphereCoords scds = new SphereCoords(numnode);

String outfile="out.txt";
scds.Print2FileXYZ(outfile, "\t", "\n", "");
	}

package sPherePlot;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class SphereCoords {
	int N;
	double theta;
	//double[] latitude;//緯度
	//double[] longitude;//経度
	
	double[][] cdsLatitude;
	double[][] cdsLongitude;
	public SphereCoords(int N_){
		N=N_;
		theta=4/Math.sqrt((double)N);
		int n=(int)(2*Math.PI/theta);
		int neq=n/2;
		//longitude =new double[n];
		cdsLatitude=new double[n][0];
		cdsLatitude[neq]=new double[n];
		cdsLongitude=new double[n][0];
		cdsLongitude[neq]=new double[n];
		for(int i=0;i<cdsLatitude[neq].length;i++){
			cdsLatitude[neq][i]=0;
			cdsLongitude[neq][i]=i*theta;
		}
		for(int i=neq+1;i<cdsLatitude.length;i++){
			int n2=(int)(2*Math.PI*Math.abs(Math.cos(theta*(i-neq)))/theta);
			//System.out.println("n="+n+" i "+i+" n2 "+n2);
			if(i<cdsLatitude.length){
				cdsLatitude[i]=new double[n2];
				cdsLongitude[i]=new double[n2];
			}
			if(neq-(i-neq)>=0){
				cdsLatitude[neq-(i-neq)]=new double[n2];
				cdsLongitude[neq-(i-neq)]=new double[n2];
			}
			
			for(int j=0;j<cdsLatitude[i].length;j++){
				if(i<cdsLatitude.length){
					cdsLatitude[i][j]=cdsLongitude[neq][i-neq];
					//cdsLongitude[i][j]=j*theta/Math.cos(cdsLatitude[i][j]);
					cdsLongitude[i][j]=j*2*Math.PI/(double)n2;
				}
				if(neq-(i-neq)>=0){
					cdsLatitude[neq-(i-neq)][j]=-cdsLongitude[neq][neq-(i-neq)];
					//cdsLongitude[neq-(i-neq)][j]=j*theta/Math.cos(cdsLatitude[neq-(i-neq)][j]);
					cdsLongitude[neq-(i-neq)][j]=j*2*Math.PI/(double)n2;
				}
				
			}
		}
		
		
		
	}
	
	public static double[] r2xyz(double r1,double r2){
		double[] ret=new double[3];
		ret[0]=Math.cos(r1)*Math.cos(r2);
		ret[1]=Math.cos(r1)*Math.sin(r2);
		ret[2]=Math.sin(r1);
		return ret;
	}
	
	public void PrintR(String sep1,String sep2,String sep3){
		for(int i=0;i<cdsLatitude.length;i++){
			for(int j=0;j<cdsLatitude[i].length;j++){
				System.out.print(cdsLatitude[i][j]+sep1+cdsLongitude[i][j]+sep2);
			}
			System.out.print(sep3);
		}
	}
	public void PrintXYZ(String sep1,String sep2,String sep3){
		for(int i=0;i<cdsLatitude.length;i++){
			for(int j=0;j<cdsLatitude[i].length;j++){
				double[] xyz=r2xyz(cdsLatitude[i][j],cdsLongitude[i][j]);
				for(int k=0;k<xyz.length;k++){
					System.out.print(xyz[k]+sep1);
				}
				System.out.print(sep2);
			}
			System.out.print(sep3);
		}
	}
	public void Print2FileXYZ(String file,String sep1,String sep2,String sep3)throws IOException{
		BufferedWriter[] bw = new BufferedWriter[1];
		bw[0] = new BufferedWriter(new FileWriter(file));
		try{
			//bw1 = new BufferedWriter(new FileWriter(file));
			for(int i=0;i<cdsLatitude.length;i++){
				for(int j=0;j<cdsLatitude[i].length;j++){
					double[] xyz=r2xyz(cdsLatitude[i][j],cdsLongitude[i][j]);
					String st="";
					
					
					for(int k=0;k<xyz.length;k++){
						st+=xyz[k]+sep1;
						//System.out.print(xyz[k]+sep1);
					}
					st+=sep2;
					bw[0].write(st);
					
				}
				bw[0].write(sep3);
			}
			
			bw[0].close();

		}catch(Exception e){
			
			System.out.println(e);
			
		}
	}

}

• 出てきたファイルをRでプロット

> library(scatterplot3d)
> data<-read.table("out.txt",sep="\t")
> scatterplot3d(data$V1,data$V2,data$V3)