Answers.Body: <p>Yes, it is indeed possible to use deep learning to provide approximate solutions to NP-hard graph theory problems. While solving NP-hard problems exactly in polynomial time is generally considered computationally infeasible, deep learning techniques can be employed to approximate solutions with impressive results in some cases.</p>
  <p>Here's how it can work:</p>
  <ol>
  <li><p><strong>Encoding Graphs</strong>: Deep learning models can take graph structures as inputs. Graph convolutional networks (GCNs), graph attention networks (GATs), and graph neural networks (GNNs) are architectures specifically designed to work with graph-structured data.</p>
  </li>
  <li><p><strong>Learning from Data</strong>: The models are trained on a dataset that includes graph instances and their corresponding optimal or near-optimal solutions. These solutions could be obtained through heuristics, metaheuristics, or other optimization methods.</p>
  </li>
  <li><p><strong>Loss Function</strong>: The loss function used during training compares the model's predictions to the known solutions. The aim is to minimize the discrepancy between the predicted and actual solutions.</p>
  </li>
  <li><p><strong>Approximate Solution</strong>: After training, the model can be used to predict solutions for new graph instances. These solutions might not be optimal, but they can be very close to optimal and obtained much faster than traditional exact methods.</p>
  </li>
  <li><p><strong>Trade-off Between Accuracy and Efficiency</strong>: The balance between solution quality and computational efficiency can be adjusted by controlling the complexity of the model, the amount of training data, and the training process itself.</p>
  </li>
  <li><p><strong>Transfer Learning</strong>: Pretrained models on one problem can be fine-tuned on related problems. This transfer learning can help speed up training and improve solution quality.</p>
  </li>
  <li><p><strong>Hyperparameter Tuning</strong>: Like in other deep learning tasks, the performance of the model can be sensitive to hyperparameters. Finding the right combination can significantly affect the quality of the approximated solutions.</p>
  </li>
  <li><p><strong>Evaluation</strong>: The quality of the approximate solutions produced by the model can be evaluated against known optimal solutions or against the solutions produced by other approximation algorithms.</p>
  </li>
  </ol>
  <p>It's important to note that the success of using deep learning for NP-hard graph problems can vary widely depending on factors such as the problem itself, the availability of suitable training data, the architecture of the neural network, and the efficiency of the training process. Some problems might benefit more from these techniques than others.</p>
  <p>Examples of NP-hard graph theory problems that have been tackled with deep learning include the Traveling Salesman Problem (TSP), Minimum Vertex Cover, Maximum Independent Set, and more. While the solutions provided by deep learning might not be guaranteed to be optimal, they often strike a good balance between solution quality and computational efficiency, making them valuable in practice.</p>
  <p>Thanks!!!</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2023-08-23T06:53:41.340Z
Answers.LastActivityDate: 2023-08-23T06:53:41.340Z
Answers.UserDisplayName: DRV
Body: <p>It is possible to use deep learning to give approximate solutions to NP-hard graph theory problems?</p>
  <p>If we take, for example, the <em>travelling salesman problem</em> (or the dominating set problem). Let's say I have a bunch of smaller examples, where I compute the optimal values by checking all possibilities, can this be then used for bigger problems?</p>
  <p>In particular, let's say I take a large graph and just optimize subgraphs of this large graph. This is perhaps a more general question: My experience with deep learning (TensorFlow/Keras) is to predict values. How can I get graph isomorphism and/or a list of local moves on the graph, to obtain a better solution? Can ML/DL give you a list of moves or local changes to get closed to an optimal value, or does it just return the predicted optimal value?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2021-03-10T21:13:43.877Z
Comments.Text: Maybe this article solves your question: [Universal Function Approximation on Graphs](https://arxiv.org/pdf/2003.06706.pdf).
Comments.UserDisplayName: Vahid Shams
Tags: <neural-networks><deep-learning><tensorflow><keras><graph-theory>
Title: It is possible to use deep learning to give approximate solutions to NP-hard graph theory problems?
UserDisplayName: Jake B.
ThreadText: # It is possible to use deep learning to give approximate solutions to NP-hard graph theory problems?
  
  (Asked by: username_0 on 2021-03-10)
  
  It is possible to use deep learning to give approximate solutions to NP-hard graph theory problems?
  
  If we take, for example, the *travelling salesman problem* (or the dominating set problem). Let's say I have a bunch of smaller examples, where I compute the optimal values by checking all possibilities, can this be then used for bigger problems?
  
  In particular, let's say I take a large graph and just optimize subgraphs of this large graph. This is perhaps a more general question: My experience with deep learning (TensorFlow/Keras) is to predict values. How can I get graph isomorphism and/or a list of local moves on the graph, to obtain a better solution? Can ML/DL give you a list of moves or local changes to get closed to an optimal value, or does it just return the predicted optimal value?
  
  **Tags:** neural-networks, deep-learning, tensorflow, keras, graph-theory
  > **Comments:**
  > **username_1**: Maybe this article solves your question: [Universal Function Approximation on Graphs](https://arxiv.org/pdf/2003.06706.pdf).  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2023-08-23. Score: 0
  
  Yes, it is indeed possible to use deep learning to provide approximate solutions to NP-hard graph theory problems. While solving NP-hard problems exactly in polynomial time is generally considered computationally infeasible, deep learning techniques can be employed to approximate solutions with impressive results in some cases.
  
  Here's how it can work:
  
  1. **Encoding Graphs**: Deep learning models can take graph structures as inputs. Graph convolutional networks (GCNs), graph attention networks (GATs), and graph neural networks (GNNs) are architectures specifically designed to work with graph-structured data.
  2. **Learning from Data**: The models are trained on a dataset that includes graph instances and their corresponding optimal or near-optimal solutions. These solutions could be obtained through heuristics, metaheuristics, or other optimization methods.
  3. **Loss Function**: The loss function used during training compares the model's predictions to the known solutions. The aim is to minimize the discrepancy between the predicted and actual solutions.
  4. **Approximate Solution**: After training, the model can be used to predict solutions for new graph instances. These solutions might not be optimal, but they can be very close to optimal and obtained much faster than traditional exact methods.
  5. **Trade-off Between Accuracy and Efficiency**: The balance between solution quality and computational efficiency can be adjusted by controlling the complexity of the model, the amount of training data, and the training process itself.
  6. **Transfer Learning**: Pretrained models on one problem can be fine-tuned on related problems. This transfer learning can help speed up training and improve solution quality.
  7. **Hyperparameter Tuning**: Like in other deep learning tasks, the performance of the model can be sensitive to hyperparameters. Finding the right combination can significantly affect the quality of the approximated solutions.
  8. **Evaluation**: The quality of the approximate solutions produced by the model can be evaluated against known optimal solutions or against the solutions produced by other approximation algorithms.
  
  It's important to note that the success of using deep learning for NP-hard graph problems can vary widely depending on factors such as the problem itself, the availability of suitable training data, the architecture of the neural network, and the efficiency of the training process. Some problems might benefit more from these techniques than others.
  
  Examples of NP-hard graph theory problems that have been tackled with deep learning include the Traveling Salesman Problem (TSP), Minimum Vertex Cover, Maximum Independent Set, and more. While the solutions provided by deep learning might not be guaranteed to be optimal, they often strike a good balance between solution quality and computational efficiency, making them valuable in practice.
  
  Thanks!!!
  
  
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