date boost

curl -XGET 'http://localhost:9200/spna/post/11003/_explain?pretty=true' -d '
{
   "size":10,
   "from":0,
   "sort":[
      "_score"
   ],
  "query": {
    "custom_filters_score": {
      "query":{
        "query_string" : {
            "fields" : ["post_title", "post_content", "post_author", "category"],
            "query" : "link building"
        }
      },
      "params": {
        "now": 1370970933000
      },
      "filters": [
        {
          "filter": {
            "exists": {
              "field": "post_date"
            }
          },
          "script": "(0.08 / ((3.16*pow(10,-11)) * abs(now - doc['post_date'].date.getMillis()) + 0.05)) + 1.0"
        }
      ]
    }
  }
}'