Some fixes to handling infinities in Percentile (and Median)

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Number/Extensions.enso

@@ -209,7 +209,8 @@ Integer.up_to n = Range this n
 
          1.equals 1.0000001 epsilon=0.001
 Number.equals : Number -> Number -> Boolean
-Number.equals that epsilon=0.0 = (this - that).abs <= epsilon
+Number.equals that epsilon=0.0 =
+    if this == that then True else (this - that).abs <= epsilon
 
 ## Returns the smaller value of `this` and `that`.
 

std-bits/table/src/main/java/org/enso/table/aggregations/Percentile.java

@@ -66,7 +66,7 @@ public Object aggregate(List<Integer> indexes) {
 
       if (current <= mid && nextCurrent > mid) {
         double second = entry.getKey();
-        return first + (second - first) * (mid_value - mid);
+        return interpolate(first, second, mid_value - mid);
       }
 
       current = nextCurrent;
@@ -75,4 +75,17 @@ public Object aggregate(List<Integer> indexes) {
     this.addProblem(new InvalidAggregation(this.getName(), -1, "Failed calculating the percentile."));
     return null;
   }
+
+  double interpolate(double first, double second, double alpha) {
+    if (Double.isInfinite(first) && Double.isInfinite(second)) {
+      if (first == second) return first;
+      else return Double.NaN;
+    }
+
+    // If both are not infinite, then if one of them is infinite, the other must be finite.
+    if (Double.isInfinite(first)) return first;
+    if (Double.isInfinite(second)) return second;
+
+    return first + (second - first) * alpha;
+  }
 }

test/Table_Tests/src/Aggregate_Spec.enso

@@ -10,6 +10,8 @@ import Standard.Test
 import Standard.Test.Problems
 import Standard.Base.Error.Problem_Behavior
 
+polyglot java import java.lang.Double
+
 type Test_Selection problem_handling=True advanced_stats=True text_concat=True text_shortest_longest=True first_last=True first_last_row_order=True std_dev=True multi_distinct=True aggregation_problems=True
 
 all_tests = Test_Selection True True True True True True True True True
@@ -935,17 +937,92 @@ aggregate_spec prefix table empty_table table_builder materialize is_database te
             m1.columns.first.at 0 . should_equal 1.1180339887499 epsilon=0.000001
             m1.columns.second.at 0 . should_equal 1.2909944487358 epsilon=0.000001
 
+    expect_null_or_nan value =
+        matches = case value of
+            Nothing -> True
+            Decimal -> Double.isNaN value
+            _       -> False
+        if matches.not then
+            loc = Meta.get_source_location 2
+            Test.fail "Expected a Nothing or NaN but got: "+value.to_text+" (at "+loc+")."
+
     Test.group prefix+"Table.aggregate should correctly handle infinities" pending=pending <|
         pos_inf = 1/0
         neg_inf = -1/0
         Test.specify " on Average" <|
-            Nothing
+            t1 = table_builder [["X", [Nothing, pos_inf, pos_inf, 0]]]
+            r1 = t1.aggregate [Average "X"]
+            r1.row_count.should_equal 1
+            m1 = materialize r1
+            m1.columns.length . should_equal 1
+            m1.columns.first.at 0 . should_equal pos_inf
+
+            t2 = table_builder [["X", [Nothing, pos_inf, neg_inf, 0]]]
+            r2 = t2.aggregate [Average "X"]
+            r2.row_count.should_equal 1
+            m2 = materialize r2
+            m2.columns.length . should_equal 1
+            expect_null_or_nan <| m2.columns.first.at 0
+
         Test.specify " on Median" (pending = resolve_pending test_selection.advanced_stats) <|
-            Nothing
+            t1 = table_builder [["X", [Nothing, neg_inf, pos_inf, 0, pos_inf, pos_inf]]]
+            r1 = t1.aggregate [Median "X"]
+            r1.row_count.should_equal 1
+            m1 = materialize r1
+            m1.columns.length . should_equal 1
+            m1.columns.first.at 0 . should_equal pos_inf
+
+            t2 = table_builder [["X", [pos_inf, pos_inf, neg_inf, neg_inf]]]
+            r2 = t2.aggregate [Median "X"]
+            r2.row_count.should_equal 1
+            m2 = materialize r2
+            m2.columns.length . should_equal 1
+            expect_null_or_nan <| m2.columns.first.at 0
+
+            t3 = table_builder [["X", [pos_inf, pos_inf, Nothing, 0, 10, 20, neg_inf, neg_inf]]]
+            r3 = t3.aggregate [Median "X"]
+            r3.row_count.should_equal 1
+            m3 = materialize r3
+            m3.columns.length . should_equal 1
+            m3.columns.first.at 0 . should_equal 10
+
+            t4 = table_builder [["X", [Nothing, pos_inf, pos_inf, 10, 12]]]
+            r4 = t4.aggregate [Median "X"]
+            r4.row_count.should_equal 1
+            m4 = materialize r4
+            m4.columns.length . should_equal 1
+            m4.columns.first.at 0 . should_equal pos_inf
+
         Test.specify " on Percentile" (pending = resolve_pending test_selection.advanced_stats) <|
-            Nothing
+            t1 = table_builder [["X", [Nothing, neg_inf, 2, 3, 4, pos_inf]]]
+            r1 = t1.aggregate [Percentile 0.3 "X"]
+            r1.row_count.should_equal 1
+            m1 = materialize r1
+            m1.columns.length . should_equal 1
+            m1.columns.first.at 0 . should_equal 2.2
+
+            t2 = table_builder [["X", [Nothing, neg_inf, neg_inf, 3, 4, pos_inf]]]
+            r2 = t2.aggregate [Percentile 0.25 "X"]
+            r2.row_count.should_equal 1
+            m2 = materialize r2
+            m2.columns.length . should_equal 1
+            m2.columns.first.at 0 . should_equal neg_inf
+
+            t3 = table_builder [["X", [Nothing, neg_inf, neg_inf, pos_inf, pos_inf, pos_inf]]]
+            r3 = t3.aggregate [Percentile 0.3 "X"]
+            r3.row_count.should_equal 1
+            m3 = materialize r3
+            m3.columns.length . should_equal 1
+            expect_null_or_nan <| m3.columns.first.at 0
+
         Test.specify " on Standard_Deviation" (pending = resolve_pending test_selection.std_dev) <|
-            Nothing
+            t1 = table_builder [["X", [neg_inf, 1]]]
+            r1 = t1.aggregate [Standard_Deviation "X" (population=True), Standard_Deviation "X" (population=False)]
+            r1.row_count.should_equal 1
+            m1 = materialize r1
+            m1.columns.length . should_equal 2
+            expect_null_or_nan <| m1.columns.first.at 0
+            expect_null_or_nan <| m1.columns.second.at 0
 
     Test.group prefix+"Table.aggregate should correctly handle NaN" pending=pending <|
         nan = 0.log 0

test/Tests/src/Data/Numbers_Spec.enso

@@ -262,4 +262,22 @@ spec =
             almost_max_long_times_three_decimal.ceil.to_decimal . should_equal almost_max_long_times_three_plus_1.to_decimal
             almost_max_long_times_three_plus_1.ceil . should_equal almost_max_long_times_three_plus_1
 
+        Test.specify "should support inexact equality comparisons" <|
+            1.0001 . equals 1.0002 epsilon=0.01 . should_be_true
+            1.0001 . equals 1.0002 epsilon=0.0000001 . should_be_false
+
+            1 . equals 2 . should_be_false
+            1 . equals (0+1) . should_be_true
+
+            inf = 1/0
+            inf . equals inf . should_be_true
+
+            neg_inf = -inf
+            neg_inf . equals neg_inf . should_be_true
+            neg_inf . equals inf . should_be_false
+
+            nan = 0.log 0
+            nan . equals nan . should_be_false
+            nan . equals 0 . should_be_false
+
 main = Test.Suite.run_main here.spec