TF-IDF per-field document frequency proof

tf-idf-things.json

PUT tf-idf-test

PUT tf-idf-test/_mapping
{
  "properties": {
    "thing": {
      "type": "text"
    },
    "secret": {
      "type": "text"
    }
  }
}

PUT tf-idf-test/_bulk
{"index":{"_id": "1"}}
{"thing":"Bananas apples lemons oranges cabbages courgettes","secret":"apples apples apples apples apples"}
{"index":{"_id": "2"}}
{"thing":"Bananas lemons oranges courgettes","secret":"apples apples apples apples apples"}
{"index":{"_id": "3"}}
{"thing":"Bananas lemons oranges cabbages courgettes","secret":"apples apples apples apples apples"}
{"index":{"_id": "4"}}
{"thing":"Apples lemons oranges cabbages courgettes","secret":"apples apples apples apples apples"}
{"index":{"_id": "5"}}
{"thing":"Bananas oranges cabbages courgettes","secret":"carrots carrots carrots carrots carrots"}

GET tf-idf-test/_explain/1
{
  "query": {
    "term": {
      "thing": "apples"
    }
  }
}