import java.util.Random; public class golay { public static final int[][] G={ {1,0,0,0,1,1,1,0,1,1,0,1,1,0,0,0,0,0,0,0,0,0,0,0}, {0,0,0,1,1,1,0,1,1,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0}, {0,0,1,1,1,0,1,1,0,1,0,1,0,0,1,0,0,0,0,0,0,0,0,0}, {0,1,1,1,0,1,1,0,1,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0}, {1,1,1,0,1,1,0,1,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0}, {1,1,0,1,1,0,1,0,0,0,1,1,0,0,0,0,0,1,0,0,0,0,0,0}, {1,0,1,1,0,1,0,0,0,1,1,1,0,0,0,0,0,0,1,0,0,0,0,0}, {0,1,1,0,1,0,0,0,1,1,1,1,0,0,0,0,0,0,0,1,0,0,0,0}, {1,1,0,1,0,0,0,1,1,1,0,1,0,0,0,0,0,0,0,0,1,0,0,0}, {1,0,1,0,0,0,1,1,1,0,1,1,0,0,0,0,0,0,0,0,0,1,0,0}, {0,1,0,0,0,1,1,1,0,1,1,1,0,0,0,0,0,0,0,0,0,0,1,0}, {1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,1} }; public static final int[][] H_transpose={ {1,0,0,0,0,0,0,0,0,0,0,0}, {0,1,0,0,0,0,0,0,0,0,0,0}, {0,0,1,0,0,0,0,0,0,0,0,0}, {0,0,0,1,0,0,0,0,0,0,0,0}, {0,0,0,0,1,0,0,0,0,0,0,0}, {0,0,0,0,0,1,0,0,0,0,0,0}, {0,0,0,0,0,0,1,0,0,0,0,0}, {0,0,0,0,0,0,0,1,0,0,0,0}, {0,0,0,0,0,0,0,0,1,0,0,0}, {0,0,0,0,0,0,0,0,0,1,0,0}, {0,0,0,0,0,0,0,0,0,0,1,0}, {0,0,0,0,0,0,0,0,0,0,0,1}, {1,0,0,0,1,1,1,0,1,1,0,1}, {0,0,0,1,1,1,0,1,1,0,1,1}, {0,0,1,1,1,0,1,1,0,1,0,1}, {0,1,1,1,0,1,1,0,1,0,0,1}, {1,1,1,0,1,1,0,1,0,0,0,1}, {1,1,0,1,1,0,1,0,0,0,1,1}, {1,0,1,1,0,1,0,0,0,1,1,1}, {0,1,1,0,1,0,0,0,1,1,1,1}, {1,1,0,1,0,0,0,1,1,1,0,1}, {1,0,1,0,0,0,1,1,1,0,1,1}, {0,1,0,0,0,1,1,1,0,1,1,1}, {1,1,1,1,1,1,1,1,1,1,1,0} }; public static final int[][] P= { {1,0,0,0,1,1,1,0,1,1,0,1}, {0,0,0,1,1,1,0,1,1,0,1,1}, {0,0,1,1,1,0,1,1,0,1,0,1}, {0,1,1,1,0,1,1,0,1,0,0,1}, {1,1,1,0,1,1,0,1,0,0,0,1}, {1,1,0,1,1,0,1,0,0,0,1,1}, {1,0,1,1,0,1,0,0,0,1,1,1}, {0,1,1,0,1,0,0,0,1,1,1,1}, {1,1,0,1,0,0,0,1,1,1,0,1}, {1,0,1,0,0,0,1,1,1,0,1,1}, {0,1,0,0,0,1,1,1,0,1,1,1}, {1,1,1,1,1,1,1,1,1,1,1,0} }; public static void print (int[] vec){ for(int i = 0; i < vec.length; i++) System.out.print(vec[i]); System.out.println(); } public static int[] mult(int []vect, int[][] mat ) { int[] result= new int[mat[0].length]; for(int i=0; i< mat[0].length; i++) { for (int j = 0; j < vect.length; j++) result[i] ^= vect[j] & mat[j][i]; } return result; } public static int[] syndrome(int []received){ System.out.println("*******Syndrome*******"); return mult(received, H_transpose); } public static int weight(int []vec){ int count = 0; for(int i=0; i< vec.length;i++){ if(vec[i]==1) count++; } return count; } public static int[] set(int []vec1, int []vec2){ int[] result=new int[vec1.length+vec2.length]; for(int i=0;i1) { int n2=0; do{ n2 = rand.nextInt(v.length) ; }while(n2 ==n); System.out.print(" ,"+n2); v[n2]=v[n2]^1; if(errnum>2) { int n3; do{ n3 = rand.nextInt(v.length); }while(n3 ==n || n3==n2); System.out.print(" ,"+n3); v[n3]=v[n3]^1; } } System.out.println(); return v; } public static void main(String[] args) { //int[] received = {1,0,0,0,0,0,1,1,0,1,0,0,1,1,0,0,0,0,0,0,0,0,0,1}; //int[] received = {0,0,0,0,0,0,1,1,0,1,0,0,1,1,0,0,0,0,0,0,0,0,0,1}; //int[] received = {1,0,1,1,1,1,1,0,1,1,1,1,0,1,0,0,1,0,0,1,0,0,1,0}; int[] codeword = {1,1,0,0,1,0,1,0,0,0,1,1}; System.out.println("*******Codeword*******"); print(codeword); int[] enc= encode(codeword); System.out.println("*******Encoded Message*******"); print(enc); int[] received= randerr(enc); System.out.println("*******Received Message with noise*******"); print(received); int[] dec; dec= decoder(received); if(dec[0]!=-1) { System.out.println("*******Decoded Message*******"); print(dec); System.out.println("*******Error pattern*******"); print(sum(dec, received)); } } }

Golay