ignore NaN values

2 files changed, 29 insertions, 3 deletions

diff --git a/eval/src/tests/eval/aggr/aggr_test.cpp b/eval/src/tests/eval/aggr/aggr_test.cpp
index aa9875a2e9f..612fb0a7630 100644
--- a/eval/src/tests/eval/aggr/aggr_test.cpp
+++ b/eval/src/tests/eval/aggr/aggr_test.cpp
@@ -87,6 +87,23 @@ TEST("require that MEDIAN aggregator works as expected") {
     aggr.next(200.0),  EXPECT_EQUAL(aggr.result(), 150.0);
 }
 
+TEST("require that MEDIAN aggregator ignores NaN values") {
+    Stash stash;
+    Aggregator &aggr = Aggregator::create(Aggr::MEDIAN, stash);
+    double my_nan = std::numeric_limits<double>::quiet_NaN();
+    aggr.first(my_nan);
+    aggr.next(my_nan);
+    aggr.next(my_nan);
+    EXPECT_TRUE(std::isnan(aggr.result()));
+    aggr.next(10.0);
+    EXPECT_EQUAL(aggr.result(), 10.0);
+    aggr.next(my_nan);
+    aggr.next(my_nan);
+    EXPECT_EQUAL(aggr.result(), 10.0);
+    aggr.next(20.0);
+    EXPECT_EQUAL(aggr.result(), 15.0);
+}
+
 TEST("require that MIN aggregator works as expected") {
     Stash stash;
     Aggregator &aggr = Aggregator::create(Aggr::MIN, stash);
@@ -117,6 +134,7 @@ float aggr_merge(const std::vector<float> &a, const std::vector<float> &b) {
 }
 
 TEST("require that aggregator merge works") {
+    float my_nan = std::numeric_limits<float>::quiet_NaN();
     EXPECT_EQUAL(aggr_merge<Avg>({1,2},{3,4}), 2.5);
     EXPECT_EQUAL(aggr_merge<Count>({1,2},{3,4}), 4.0);
     EXPECT_EQUAL(aggr_merge<Prod>({1,2},{3,4}), 24.0);
@@ -125,6 +143,7 @@ TEST("require that aggregator merge works") {
     EXPECT_EQUAL(aggr_merge<Median>({1,2},{3,4}), 2.5);
     EXPECT_EQUAL(aggr_merge<Median>({1,2},{3,4,5}), 3);
     EXPECT_EQUAL(aggr_merge<Median>({0,1,2},{3,4}), 2);
+    EXPECT_EQUAL(aggr_merge<Median>({my_nan,2,my_nan},{my_nan,4}), 3);
     EXPECT_EQUAL(aggr_merge<Min>({1,2},{3,4}), 1.0);
 }
 
diff --git a/eval/src/vespa/eval/eval/aggr.h b/eval/src/vespa/eval/eval/aggr.h
index 25b0a899efd..2412008db61 100644
--- a/eval/src/vespa/eval/eval/aggr.h
+++ b/eval/src/vespa/eval/eval/aggr.h
@@ -8,6 +8,7 @@
 #include <vector>
 #include <map>
 #include <algorithm>
+#include <cmath>
 
 namespace vespalib {
 
@@ -126,11 +127,17 @@ private:
     std::vector<T> _seen;
 public:
     constexpr Median() : _seen() {}
-    constexpr Median(T value) : _seen({value}) {}
-    constexpr void sample(T value) { _seen.push_back(value); }
+    constexpr Median(T value) : _seen() {
+        sample(value);
+    }
+    constexpr void sample(T value) {
+        if (!std::isnan(value)) {
+            _seen.push_back(value);
+        }
+    }
     constexpr void merge(const Median &rhs) {
         for (T value: rhs._seen) {
-            _seen.push_back(value);
+            sample(value);
         }
     };
     constexpr T result() const {