solr/contrib/ltr/src/test-files/modelExamples/external_model2.json

{
    "class":"org.apache.solr.ltr.model.LinearModel",
    "name":"externalmodel2",
    "store": "fstore2",
    "features":[
        { "name": "docPopularity"}
    ],
    "params":{
        "weights": {
            "docPopularity": 0.5
        }
    }
}