Back

Explore Courses Blog Tutorials Interview Questions
0 votes
1 view
in AI and Deep Learning by (50.2k points)

I'm trying to write Hopfield neural network class in Java, but the network doesn't want to recognize patterns. And I can't understand where is the mistake. Network represents with the interconnection matrix w[n][n]. When the network is taught with some standard pattern I change the interconnection matrix with the following method:

private void teaching(int[] pattern) 

{ //teaching for(int i=0; i<n; i++) 

 for(int j=0; j<n; j++) 

 if(i==j) w[i][j]=0; 

 Else

 w[i][j] += pattern[i]*pattern[j]; 

 } }

Then I try to recognize the standard patterns in some similar patterns. The process should be stopped when the state of neurons stop changing or when threshold (65535 iterations) is overcome:

private int[] recognition(int[] pattern) { int net=0, s, j=0; int[] previousState = new int[n]; do{ System.arraycopy(pattern, 0, previousState, 0, n); int r = generateRandom(n); for(int i=0; i<n; i++) net+=pattern[i]*w[i][r]; s = signum(net); pattern[r] = s; j++; if(j>iterThreshold) { System.err.println("Threshold overcome."); return pattern; } }while(!Arrays.equals(pattern, previousState)); return pattern; } signum is an activation function: private static int signum(int x) { //activation function if(x>0) return 1; else return -1; }

The recognition process stops only when the threshold is passed. And out pattern doesn't look like a standard pattern. Please help to find the mistake. Thank you in advance.

1 Answer

0 votes
by (108k points)

You have not initialized the net value to “0” inside the do statement in the recognition function:

private int[] recognition(int[] pattern) 

int net=0, s, j=0; 

 ... 

 do{ 

 net=0; 

 for(int i=0; i<n; i++) 

 net+=pattern[i]*w[i][r];

 ...

  }

}

If you wish to know about Neural Network then visit this Neural Network Tutorial.

Welcome to Intellipaat Community. Get your technical queries answered by top developers!

28.4k questions

29.7k answers

500 comments

94.2k users

Browse Categories

...