Elasticsearch boosting score for values in array - elasticsearch

Question

I am trying to implement scoring of documents based on certain values stored in array via elasticsearch. For example, if my document contain an array object like this:
Document 1:
{
id: "test",
marks: [{
"classtype" : "x1",
"value": 90
}]
}
Document 2:
{
id: "test2",
marks: [{
"classtype" : "x1",
"value": 50
},{
"classtype" : "x2",
"value": 60
}]
}
I want my output scores to be boosted by choosing boosting factor on basis of "classtype", but applicable on "value".
equivalent code would be:
var boostingfactor = {
"x1" : 1,
"x2" : 10
}
var smartscore = 0;
marks.forEach(function(mark){
return smartscore += mark.value * boostingfactor[mark.classtype];
});
return smartscore;
I have tried elasticsearch query on integer values, but not sure if same can be done for values present in array. I also tried writing scripts in elasticsearch's painless language, but couldnt find right way to filter values based on classtype.
POST /student/_search
{
"query": {
"function_score": {
"script_score" : {
"script" : {
"params": {
"x1": 1,
"x2": 10
},
"source": "params[doc['marks.classtype']] * marks.value"
}
}
}
}
}
Expected result is scoring of 90 (90*1) for sample document 1 and 650 (50*1+60*10) for document 2 but above query fails with exception:
{
"type": "script_exception",
"reason": "runtime error",
"script_stack": [
"params[doc['marks.classtype'].value]",
" ^---- HERE"
],
"script": "params[doc['marks.classtype'].value]",
"lang": "painless"
}
Is it possible to accomplish the result via modifying script?
Elasticsearch version: 7.1.0

Answer 1

I was able to read through array values using following script:
"script_score" : {
"script" : {
"params": {
"x1": 5,
"x2": 10
},
"source": "double sum = 0.0; for (item in params._source.marks) { sum += item.value * params[item.classtype]; } return sum;"
}
}