How Neural Networks Solve the XOR Problem by Aniruddha Karajgi
How Neural Networks Solve the XOR Problem by Aniruddha Karajgi

The data flow graph as a whole is a complete description of the calculations that are implemented within the session and performed on CPU or GPU devices. Lalit Kumar is an avid learner and loves to share his learnings. He is a Quality Analyst by profession and have 15 years of experience. SGD works well for shallow networks and for our XOR example we can use sgd.

  • It is a problem that is not linearly separable, meaning that it cannot be solved by using a single layer perceptron.
  • It doesn’t matter how many linear layers we stack, they’ll always be matrix in the end.
  • From previous scenarios, we had found the values of W0, W1, W2 to be -3,2,2 respectively.
  • Keras by default uses “adam” optimizer, so we have also used the same in our solution of XOR and it works well for us.
  • For any given plaintext input, the ciphertext result is just as likely to be either 0 or 1.

After visualizing in 3D, the X’s and the O’s now look separable. The red plane can now separate the two points or classes. In conclusion, the above points are linearly separable in higher dimensions.

The XOR problem is exceptionally interesting to neural network researchers because it is a complex binary function that cannot be solved by a neural network. This problem is difficult to solve because it requires the ability to learn complex patterns and relationships. Neural networks are well suited to solving this problem because they are capable of learning complex patterns and relationships.

Activation used in our present model are “relu” for hidden layer and “sigmoid” for output layer. The choice appears good for solving this problem and can also reach to a solution easily. In some practical cases e.g. when collecting product reviews online for various parameters and if the parameters are optional fields we may get some missing input values. In such case, we can use various approaches like setting the missing value to most occurring value of the parameter or set it to mean of the values. One interesting approach could be to use neural network in reverse to fill missing parameter values. Where $y_o$ is the result of the output layer (the prediction) and $y$ is the true value given in the training data.

It is worth noting that an MLP can have any number of units in its input, hidden and output layers. The architecture used here is designed specifically for the XOR problem. The perceptron is a type of feed-forward network, which means the process of generating an output — known as forward propagation — flows in one direction from the input layer to the output layer.

XOR-jax

I decided to check online resources, but as of the time of writing this, there was really no explanation on how to go about it. So after personal readings, I finally understood how to go about it, which is the reason for this medium post. As we have 4 choices of input, the weights must be such that the condition of AND gate is satisfied for all the input points. The classic multiplication algorithm will have complexity as O(n3). The XOR gate can be usually termed as a combination of NOT and AND gates and this type of logic finds its vast application in cryptography and fault tolerance. Let us try to understand the XOR operating logic using a truth table.

  • Our main aim is to find the value of weights or the weight vector which will enable the system to act as a particular gate.
  • Perceptrons include a single layer of input units — including one bias unit — and a single output unit (see figure 2).
  • Hidden layers are those layers with nodes other than the input and output nodes.
  • We’ll adjust it until we get an accurate output each time, and we’re confident the neural network has learned the pattern.

One simple approach is to set all weights to 0 initially, but in this case network will behave like a linear model as the gradient of loss w.r.t. all weights will be same in each layer respectively. It will make network symmetric and thus the neural network looses it’s advantages of being able to map non linearity and behaves much like a linear model. For learning to happen, we need to train our model with sample input/output pairs, such learning is called supervised learning. Supervised learning approach has given amazing result in deep learning when applied to diverse tasks like face recognition, object identification, NLP tasks. Most of the practically applied deep learning models in tasks such as robotics, automotive etc are based on supervised learning approach only.

OR logical function

The perfect balance of XOR makes it an ideal candidate for cryptography. For any given plaintext input, the ciphertext result is just as likely to be either 0 or 1. This is due to the fact that the key bits are truly random. The table below shows all four possible pairs of plaintext and key bits. This enhances the training performance of the model and convergence is faster with LeakyReLU in this case. The linear separable data points appear to be as shown below.

Explanation of Maths behind Neural Network:

Some advanced tasks like language translation, text summary generation have complex output space which we will not consider in this article. The activation function in output layer is selected based on the output space. For a binary classification task sigmoid activations is correct choice while for multi class classification softmax is the most populary choice. The XOR problem with neural networks can be solved by using Multi-Layer Perceptrons or a neural network architecture with an input layer, hidden layer, and output layer. So during the forward propagation through the neural networks, the weights get updated to the corresponding layers and the XOR logic gets executed. The Neural network architecture to solve the XOR problem will be as shown below.

Perceptrons, Logical Functions, and the XOR problem

The points labeled with 1 must remain together in one side of line. The other ones (labelled with 0) stay on the other side of the line. Data Science Stack Exchange is a question and answer site for Data science professionals, Machine Learning specialists, and those interested in learning more about the field. DEV Community — A constructive and inclusive social network for software developers. Once unpublished, all posts by jbahire will become hidden and only accessible to themselves.

Please note that in a real world scenario our predictions would be tested against data that the neural network hasn’t seen during the training. That’s because we usually want to see if our model generalizes well. In other words, does it work with new data or does it just memorize all the data and expected results it had seen in the training phase? However, xor neural network with this toy task there are really only our four states and four expected outputs. The xor problem is a problem in neural networks where two input values produce an output of 1, but when the input values are the same, the output is 0. This can be seen as a problem because it means that the neural network cannot learn the concept of exclusive Or.

In our recent article on machine learning we’ve shown how to get started with machine learning without assuming any prior knowledge. We ended up running our very first neural network to implement an XOR gate. ANN is based on a set of connected nodes called artificial neurons (similar to biological neurons in the brain of animals). Each connection (similar to a synapse) between artificial neurons can transmit a signal from one to the other. The artificial neuron receiving the signal can process it and then signal to the artificial neurons attached to it. Artificial neural networks (ANNs), or connectivist systems are computing systems inspired by biological neural networks that make up the brains of animals.

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