{
  "id": 274260,
  "title": "The current evaluation accepts any binary adjacency matrix. By design or mistake?",
  "url": "/competitions/kddbr-2021/discussion/274260",
  "author_name": "",
  "post_date": "2021-09-24T22:08:13.020417200Z",
  "votes": 3,
  "comment_count": 2,
  "views": 0,
  "content": "<p>Firstly, it's nice to be part of KDD-BR again!. I started looking at the competition 2 days ago, and  prototyped a quick solution. I was planning to implement a greedy or beam search later to enforce a tour, but maybe that won't be necessary anymore: it turns out that, against my expectations, <em>the evaluation accepts any binary adjacency matrix, whether it is a tour or not</em>. Maybe this is intended, as otherwise you'd probably want to use the optimality gap as the metric (I think?).</p>\n<p>Nonetheless, I am still confused about this. Am I the only one? If this adjacency matrix must follow more constraints, I reckon they should be checked  for at evaluation time.</p>",
  "messages": [
    {
      "id": "1523048",
      "postDate": "09/24/2021 22:08:13",
      "content": "<p>Firstly, it's nice to be part of KDD-BR again!. I started looking at the competition 2 days ago, and  prototyped a quick solution. I was planning to implement a greedy or beam search later to enforce a tour, but maybe that won't be necessary anymore: it turns out that, against my expectations, <em>the evaluation accepts any binary adjacency matrix, whether it is a tour or not</em>. Maybe this is intended, as otherwise you'd probably want to use the optimality gap as the metric (I think?).</p>\n<p>Nonetheless, I am still confused about this. Am I the only one? If this adjacency matrix must follow more constraints, I reckon they should be checked  for at evaluation time.</p>",
      "rawMarkdown": "Firstly, it's nice to be part of KDD-BR again!. I started looking at the competition 2 days ago, and  prototyped a quick solution. I was planning to implement a greedy or beam search later to enforce a tour, but maybe that won't be necessary anymore: it turns out that, against my expectations, *the evaluation accepts any binary adjacency matrix, whether it is a tour or not*. Maybe this is intended, as otherwise you'd probably want to use the optimality gap as the metric (I think?).\n\nNonetheless, I am still confused about this. Am I the only one? If this adjacency matrix must follow more constraints, I reckon they should be checked  for at evaluation time.",
      "votes": null
    },
    {
      "id": "1525445",
      "postDate": "09/27/2021 12:45:19",
      "content": "<p>Hi Bruno,</p>\n<p>This is a Kaggle limitation.<br>\nEffectively, we are measuring how well you can <strong>predict whether an edge is present or not</strong> in the optimal solution.</p>\n<p>Unfortunately, there are some side effects of such a limitation:</p>\n<ul>\n<li>We can not check if the solution is valid (a tour) or not;</li>\n<li>Given two solutions A and B, it is possible that solution A has a higher F1-Score than solution B in the predictive task while yielding longer tours.</li>\n</ul>",
      "rawMarkdown": "Hi Bruno,\n\nThis is a Kaggle limitation.\nEffectively, we are measuring how well you can **predict whether an edge is present or not** in the optimal solution.\n\nUnfortunately, there are some side effects of such a limitation:\n\n- We can not check if the solution is valid (a tour) or not;\n- Given two solutions A and B, it is possible that solution A has a higher F1-Score than solution B in the predictive task while yielding longer tours.",
      "votes": null
    },
    {
      "id": "1526041",
      "postDate": "09/27/2021 19:50:06",
      "content": "<p>I see,  too bad there's no built-in way to enforce this. I'll keep on predicting these raw adjacency matrices that are not necessarily tours, if that's alright by you guys.</p>",
      "rawMarkdown": "I see,  too bad there's no built-in way to enforce this. I'll keep on predicting these raw adjacency matrices that are not necessarily tours, if that's alright by you guys.",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 1525445,
      "author_name": "profverri",
      "author_url": "",
      "post_date": "09/27/2021 12:45:19",
      "content": "<p>Hi Bruno,</p>\n<p>This is a Kaggle limitation.<br>\nEffectively, we are measuring how well you can <strong>predict whether an edge is present or not</strong> in the optimal solution.</p>\n<p>Unfortunately, there are some side effects of such a limitation:</p>\n<ul>\n<li>We can not check if the solution is valid (a tour) or not;</li>\n<li>Given two solutions A and B, it is possible that solution A has a higher F1-Score than solution B in the predictive task while yielding longer tours.</li>\n</ul>",
      "votes": null,
      "replies": [
        {
          "id": 1526041,
          "author_name": "isonettv",
          "author_url": "",
          "post_date": "09/27/2021 19:50:06",
          "content": "<p>I see,  too bad there's no built-in way to enforce this. I'll keep on predicting these raw adjacency matrices that are not necessarily tours, if that's alright by you guys.</p>",
          "votes": null,
          "replies": []
        }
      ]
    }
  ],
  "raw_markdown_by_id": {
    "1523048": "Firstly, it's nice to be part of KDD-BR again!. I started looking at the competition 2 days ago, and  prototyped a quick solution. I was planning to implement a greedy or beam search later to enforce a tour, but maybe that won't be necessary anymore: it turns out that, against my expectations, *the evaluation accepts any binary adjacency matrix, whether it is a tour or not*. Maybe this is intended, as otherwise you'd probably want to use the optimality gap as the metric (I think?).\n\nNonetheless, I am still confused about this. Am I the only one? If this adjacency matrix must follow more constraints, I reckon they should be checked  for at evaluation time.",
    "1525445": "Hi Bruno,\n\nThis is a Kaggle limitation.\nEffectively, we are measuring how well you can **predict whether an edge is present or not** in the optimal solution.\n\nUnfortunately, there are some side effects of such a limitation:\n\n- We can not check if the solution is valid (a tour) or not;\n- Given two solutions A and B, it is possible that solution A has a higher F1-Score than solution B in the predictive task while yielding longer tours.",
    "1526041": "I see,  too bad there's no built-in way to enforce this. I'll keep on predicting these raw adjacency matrices that are not necessarily tours, if that's alright by you guys."
  },
  "source": "meta"
}