Decay functions currently only use the first value in a field that contains
multiple values to compute the distance to the origin. Instead, it should
consider all distances if more values are in the field and then use
one of min/max/sum/avg which is defined by the user.
Relates to #3960closes#5940
The `field_value_factor` function uses the value of a field in the
document to influence the score.
A query that looks like:
{
"query": {
"function_score": {
"query": {"match": { "body": "foo" }},
"functions": [
{
"field_value_factor": {
"field": "popularity",
"factor": 1.1,
"modifier": "square"
}
}
],
"score_mode": "max",
"boost_mode": "sum"
}
}
}
Would have the score modified by:
square(1.1 * doc['popularity'].value)
Closes#5519
- "boost" should be "boost_factor"
- "mult" should be "multiply"
Also, store combine function names in ImmutableMap instead of iterating
over all possible names each time.
closes#3872 for master
