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

{
    "class":"org.apache.solr.ltr.model.MultipleAdditiveTreesModel",
    "name":"multipleadditivetreesmodel_no_features",
    "params":{
        "trees": [
            {
                "weight" : "2f",
                "root": {
                    "value" : "-10"
                }
            }
        ]
    }
}