anchor.diff:  |`doc_values` |Set to `true` to store field values in a column-stride fashion.
   Automatically set to `true` when the fielddata format is `doc_values`.
   
  -|`precision_step` |The precision step (influences the number of terms 
  +|`precision_step` |The precision step (influences the number of terms
   generated for each number value). Defaults to `16`.
   
   |`boost` |The boost value. Defaults to `1.0`.
  
positive.code: |`doc_values` |Set to `true` to store field values in a column-stride fashion.
  Automatically set to `true` when the fielddata format is `doc_values`.
  
  |`precision_step` |The precision step (influences the number of terms 
  generated for each number value). Defaults to `16` for `long`, `double`,
  `8` for `short`, `integer`, `float`, and `2147483647` for `byte`.
  
  
negative.code:    "book":{
        "properties":{
           "title":{
              "type":"string", "similarity":"BM25"
           }
        }
     }
  