Upgrade ChiSqSelectorModel to spark 3.2.0 compatable design

sort filterIndiecs before using it

Author: austinzh

mleap-core/src/main/scala/ml/combust/mleap/core/feature/ChiSqSelectorModel.scala

@@ -10,22 +10,23 @@ import scala.collection.mutable
 /**
   * Created by hollinwilkins on 12/27/16.
   */
-@SparkCode(uri = "https://github.com/apache/spark/blob/v2.0.0/mllib/src/main/scala/org/apache/spark/mllib/feature/ChiSqSelector.scala")
+@SparkCode(uri = "https://github.com/apache/spark/blob/v3.2.0/mllib/src/main/scala/org/apache/spark/mllib/feature/ChiSqSelector.scala")
 case class ChiSqSelectorModel(filterIndices: Seq[Int],
                               inputSize: Int) extends Model {
+  private val sortedFilterIndices = filterIndices.sorted
   def apply(features: Vector): Vector = {
     features match {
       case SparseVector(size, indices, values) =>
-        val newSize = filterIndices.length
+        val newSize = sortedFilterIndices.length
         val newValues = mutable.ArrayBuilder.make[Double]
         val newIndices = mutable.ArrayBuilder.make[Int]
         var i = 0
         var j = 0
         var indicesIdx = 0
         var filterIndicesIdx = 0
-        while (i < indices.length && j < filterIndices.length) {
+        while (i < indices.length && j < sortedFilterIndices.length) {
           indicesIdx = indices(i)
-          filterIndicesIdx = filterIndices(j)
+          filterIndicesIdx = sortedFilterIndices(j)
           if (indicesIdx == filterIndicesIdx) {
             newIndices += j
             newValues += values(i)
@@ -43,7 +44,7 @@ case class ChiSqSelectorModel(filterIndices: Seq[Int],
         Vectors.sparse(newSize, newIndices.result(), newValues.result())
       case DenseVector(values) =>
         val values = features.toArray
-        Vectors.dense(filterIndices.map(i => values(i)).toArray)
+        Vectors.dense(sortedFilterIndices.map(i => values(i)).toArray)
       case other =>
         throw new UnsupportedOperationException(
           s"Only sparse and dense vectors are supported but got ${other.getClass}.")
@@ -52,5 +53,5 @@ case class ChiSqSelectorModel(filterIndices: Seq[Int],
 
   override def inputSchema: StructType = StructType("input" -> TensorType.Double(inputSize)).get
 
-  override def outputSchema: StructType = StructType("output" -> TensorType.Double(filterIndices.length)).get
+  override def outputSchema: StructType = StructType("output" -> TensorType.Double(sortedFilterIndices.length)).get
 }

mleap-core/src/test/scala/ml/combust/mleap/core/feature/ChiSqSelectorModelSpec.scala

@@ -2,11 +2,22 @@ package ml.combust.mleap.core.feature
 
 import ml.combust.mleap.core.types.{StructField, TensorType}
 import org.scalatest.FunSpec
+import org.apache.spark.ml.linalg.{DenseVector, SparseVector, Vector, Vectors}
 
 class ChiSqSelectorModelSpec extends FunSpec {
 
   describe("input/output schema"){
-    val model = new ChiSqSelectorModel(Seq(1,2,3), 3)
+    val model = new ChiSqSelectorModel(Seq(2,3, 1), 3)
+
+    it("Dense vector work with unsorted indices") {
+      val vector = Vectors.dense(1.0,2.0,3.0,4.0)
+      assert(model(vector) == Vectors.dense(2.0, 3.0, 4.0))
+    }
+
+    it("Sparse vector work with unsorted indices") {
+      val vector = Vectors.sparse(size = 4, indices=Array(0,1,2,3), values = Array(1.0,2.0,3.0,4.0))
+      assert(model(vector) == Vectors.sparse(size=3, indices=Array(0,1,2), values=Array(2.0,3.0,4.0)))
+    }
 
     it("Has the right input schema") {
       assert(model.inputSchema.fields ==