private NativeRankTypeDefinition createEmptyRankType(RankType type) {
        NativeRankTypeDefinition rank = new NativeRankTypeDefinition(type);
        rank.addTable(new NativeTable(NativeTable.Type.FIRST_OCCURRENCE, "linear(0,0)"));
        rank.addTable(new NativeTable(NativeTable.Type.OCCURRENCE_COUNT, "linear(0,0)"));
        rank.addTable(new NativeTable(NativeTable.Type.PROXIMITY, "linear(0,0)"));
        rank.addTable(new NativeTable(NativeTable.Type.REVERSE_PROXIMITY, "linear(0,0)"));
        rank.addTable(new NativeTable(NativeTable.Type.WEIGHT, "linear(0,0)"));
        return rank;
    }
Returns the default rank type (about)
config-model/src/main/java/com/yahoo/schema/derived/NativeRankTypeDefinitionSet.java