Fix relative difference scala (apache#14417)

* Fix relative difference scala

* Increase number of cases for scala arange test

* Add cases where arange produces NDArray of [0]

* Remote whitespace

scala-package/core/src/test/scala/org/apache/mxnet/CheckUtils.scala

@@ -21,13 +21,13 @@ object CheckUtils {
   def reldiff(a: NDArray, b: NDArray): Float = {
     val diff = NDArray.sum(NDArray.abs(a - b)).toScalar
     val norm = NDArray.sum(NDArray.abs(a)).toScalar
-    diff / norm
+    if (diff < Float.MinPositiveValue) diff else diff / norm
   }
 
   def reldiff(a: Array[Float], b: Array[Float]): Float = {
     val diff =
       (a zip b).map { case (aElem, bElem) => Math.abs(aElem - bElem) }.sum
     val norm: Float = a.reduce(Math.abs(_) + Math.abs(_))
-    diff / norm
+    if (diff < Float.MinPositiveValue) diff else diff / norm
   }
 }

scala-package/core/src/test/scala/org/apache/mxnet/NDArraySuite.scala

@@ -355,6 +355,13 @@ class NDArraySuite extends FunSuite with BeforeAndAfterAll with Matchers {
       val result3 = 0f to stop by 1f
       val range3 = NDArray.arange(stop)
       assert(CheckUtils.reldiff(result3.toArray, range3.toArray) <= 1e-4f)
+
+      val stop4 = Math.abs(stop)
+      val step4 = stop4 + Math.abs(scala.util.Random.nextFloat())
+      val result4 = (0.0 until stop4.toDouble by step4.toDouble)
+        .flatMap(x => Array.fill[Float](repeat)(x.toFloat))
+      val range4 = NDArray.arange(stop4, step = step4, repeat = repeat)
+      assert(CheckUtils.reldiff(result4.toArray, range4.toArray) <= 1e-4f)
     }
   }