Hopfield neural network

Question

do you know any application beside pattern recog. worthe in order to implement Hopfield neural network model?

Answer 1

Recurrent neural networks (of which hopfield nets are a special type) are used for several tasks in sequence learning:

• Sequence Prediction (Map a history of stock values to the expected value in the next timestep)
• Sequence classification (Map each complete audio snippet to a speaker)
• Sequence labelling (Map an audio snippet to the sentence spoken)
• Non-markovian reinforcement learning (e.g. tasks that require deep memory as the T-Maze benchmark)

I am not sure what you mean by "pattern recognition" exactly, since it basically is a whole field into which each task for which neural networks can be used fits.

Answer 2

You can use Hopfield network for optimization problems as well.

Answer 3

You can checkout this repository --> Hopfield Network

There you have an example for test a pattern after train the Network off-line. This is the test

 @Test
 public void HopfieldTest(){
     double[] p1 = new double[]{1.0, -1.0,1.0,-1.0,1.0,-1.0,1.0,-1.0,1.0};
     double[] p2 = new double[]{1.0, 1.0,1.0,-1.0,1.0,-1.0,-1.0,1.0,-1.0};
     double[] p3 = new double[]{1.0, 1.0,-1.0,-1.0,1.0,-1.0,-1.0,1.0,-1.0};

     ArrayList<double[]> patterns = new ArrayList<>();
     patterns.add(p1);
     patterns.add(p2);

     Hopfield h = new Hopfield(9, new StepFunction());

     h.train(patterns); //train and load the Weight matrix

     double[] result = h.test(p3); //Test a pattern

     System.out.println("\nConnections of Network: " + h.connections() + "\n"); //show Neural connections
     System.out.println("Good recuperation capacity of samples: " + Hopfield.goodRecuperation(h.getWeights().length) + "\n");
     System.out.println("Perfect recuperation capacity of samples: " + Hopfield.perfectRacuperation(h.getWeights().length) + "\n");
     System.out.println("Energy: " + h.energy(result));

     System.out.println("Weight Matrix");
     Matrix.showMatrix(h.getWeights());
     System.out.println("\nPattern result of test");
     Matrix.showVector(result);

     h.showAuxVector();
 }

And after run the test you can see

Running HopfieldTest

Connections of Network: 72

Good recuperation capacity of samples: 1

Perfect recuperation capacity of samples: 1

Energy: -32.0

Weight Matrix
 0.0        0.0     2.0    -2.0      2.0       -2.0       0.0       0.0     0.0
 0.0        0.0     0.0     0.0      0.0        0.0      -2.0       2.0    -2.0
 2.0        0.0     0.0    -2.0      2.0       -2.0       0.0       0.0     0.0
-2.0        0.0    -2.0     0.0     -2.0        2.0       0.0       0.0     0.0
 2.0        0.0     2.0    -2.0      0.0       -2.0       0.0       0.0     0.0
-2.0        0.0    -2.0     2.0     -2.0        0.0       0.0       0.0     0.0
 0.0       -2.0     0.0     0.0      0.0        0.0       0.0      -2.0     2.0
 0.0        2.0     0.0     0.0      0.0        0.0      -2.0       0.0    -2.0
 0.0       -2.0     0.0     0.0      0.0        0.0       2.0      -2.0     0.0

Pattern result of test 

 1.0        1.0     1.0     -1.0     1.0       -1.0      -1.0       1.0     -1.0
-------------------------
The auxiliar vector is empty

I hope this can help you