bugfix: adding data equal to the lower bound of a histogram threw an exception while lower values were fitted appropriately

src/Numerics/Statistics/Histogram.cs

@@ -344,7 +344,7 @@ namespace MathNet.Numerics.Statistics
             // Sort if needed.
             LazySort();
 
-            if (d < LowerBound)
+            if (d <= LowerBound)
             {
                 // Make the lower bound just slightly smaller than the datapoint so it is contained in this bucket.
                 _buckets[0].LowerBound = d.Decrement();

src/UnitTests/StatisticsTests/HistogramTests.cs

@@ -348,6 +348,18 @@ namespace MathNet.Numerics.UnitTests.StatisticsTests
             Assert.AreEqual(3, h[0].Count);
         }
 
+        /// <summary>
+        /// Add data equal to the lower bound of a histogram.
+        /// </summary>
+        [Test]
+        public void AddDataEqualToLowerBound()
+        {
+            var h = new Histogram(new[] { 1.0, 5.0, 10.0 }, 3, 0.0, 10.0);
+            Assert.DoesNotThrow(() => h.AddData(0.0));
+            
+            Assert.AreEqual(2, h[0].Count);
+        }
+
         /// <summary>
         /// Small dataset histogram without bounds.
         /// </summary>