metrics: skip `not a number` values when computinh the sum and std_dev

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>

diff --git a/src/metrics/metrics_base.nit b/src/metrics/metrics_base.nit
index 605f4d3..ebd05ae 100644 (file)
--- a/src/metrics/metrics_base.nit
+++ b/src/metrics/metrics_base.nit
@@ -299,7 +299,10 @@ class FloatMetric
 
        redef fun sum do
                var sum = 0.0
-               for v in values.values do sum += v
+               for v in values.values do
+                       if v.is_nan then continue
+                       sum += v
+               end
                return sum
        end
 
@@ -337,6 +340,7 @@ class FloatMetric
        redef fun std_dev do
                var sum = 0.0
                for value in values.values do
+                       if value.is_nan then continue
                        sum += (value - avg).pow(2.to_f)
                end
                return (sum / values.length.to_f).sqrt