fix: add checks for bm25 k1 and b in sparse index checker (#36907)

issue: https://github.com/milvus-io/milvus/issues/36883,
https://github.com/milvus-io/milvus/issues/35853

Signed-off-by: Buqian Zheng <zhengbuqian@gmail.com>

pkg/util/indexparamcheck/constraints.go

@@ -45,6 +45,9 @@ const (
 	// Sparse Index Param
 	SparseDropRatioBuild = "drop_ratio_build"
 
+	BM25K1 = "bm25_k1"
+	BM25B  = "bm25_b"
+
 	MaxBitmapCardinalityLimit = 1000
 )
 

pkg/util/indexparamcheck/sparse_float_vector_base_checker.go

@@ -29,6 +29,22 @@ func (c sparseFloatVectorBaseChecker) CheckTrain(params map[string]string) error
 		}
 	}
 
+	bm25K1Str, exist := params[BM25K1]
+	if exist {
+		bm25K1, err := strconv.ParseFloat(bm25K1Str, 64)
+		if err != nil || bm25K1 < 0 || bm25K1 > 3 {
+			return fmt.Errorf("invalid bm25_k1: %s, must be in range [0, 3]", bm25K1Str)
+		}
+	}
+
+	bm25BStr, exist := params[BM25B]
+	if exist {
+		bm25B, err := strconv.ParseFloat(bm25BStr, 64)
+		if err != nil || bm25B < 0 || bm25B > 1 {
+			return fmt.Errorf("invalid bm25_b: %s, must be in range [0, 1]", bm25BStr)
+		}
+	}
+
 	return nil
 }
 

pkg/util/indexparamcheck/sparse_float_vector_base_checker_test.go

@@ -0,0 +1,89 @@
+package indexparamcheck
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/milvus-io/milvus-proto/go-api/v2/schemapb"
+)
+
+func Test_sparseFloatVectorBaseChecker_StaticCheck(t *testing.T) {
+	validParams := map[string]string{
+		Metric: "IP",
+	}
+
+	invalidParams := map[string]string{
+		Metric: "L2",
+	}
+
+	c := newSparseFloatVectorBaseChecker()
+
+	t.Run("valid metric", func(t *testing.T) {
+		err := c.StaticCheck(validParams)
+		assert.NoError(t, err)
+	})
+
+	t.Run("invalid metric", func(t *testing.T) {
+		err := c.StaticCheck(invalidParams)
+		assert.Error(t, err)
+	})
+}
+
+func Test_sparseFloatVectorBaseChecker_CheckTrain(t *testing.T) {
+	validParams := map[string]string{
+		SparseDropRatioBuild: "0.5",
+		BM25K1:               "1.5",
+		BM25B:                "0.5",
+	}
+
+	invalidDropRatio := map[string]string{
+		SparseDropRatioBuild: "1.5",
+	}
+
+	invalidBM25K1 := map[string]string{
+		BM25K1: "3.5",
+	}
+
+	invalidBM25B := map[string]string{
+		BM25B: "1.5",
+	}
+
+	c := newSparseFloatVectorBaseChecker()
+
+	t.Run("valid params", func(t *testing.T) {
+		err := c.CheckTrain(validParams)
+		assert.NoError(t, err)
+	})
+
+	t.Run("invalid drop ratio", func(t *testing.T) {
+		err := c.CheckTrain(invalidDropRatio)
+		assert.Error(t, err)
+	})
+
+	t.Run("invalid BM25K1", func(t *testing.T) {
+		err := c.CheckTrain(invalidBM25K1)
+		assert.Error(t, err)
+	})
+
+	t.Run("invalid BM25B", func(t *testing.T) {
+		err := c.CheckTrain(invalidBM25B)
+		assert.Error(t, err)
+	})
+}
+
+func Test_sparseFloatVectorBaseChecker_CheckValidDataType(t *testing.T) {
+	c := newSparseFloatVectorBaseChecker()
+
+	t.Run("valid data type", func(t *testing.T) {
+		field := &schemapb.FieldSchema{DataType: schemapb.DataType_SparseFloatVector}
+		err := c.CheckValidDataType(field)
+		assert.NoError(t, err)
+	})
+
+	t.Run("invalid data type", func(t *testing.T) {
+		field := &schemapb.FieldSchema{DataType: schemapb.DataType_FloatVector}
+		err := c.CheckValidDataType(field)
+		assert.Error(t, err)
+	})
+}