Prepare v2.1.2 release

.github/workflows/Snapshot.yml

@@ -10,8 +10,8 @@ jobs:
     with:
       dotnet-version: '10.0.x'
       project-names: 'Numerics'
-      # Snapshot workflow appends .<run_number>-dev, so this tracks the next development patch after v2.1.1.
-      version: '2.1.2'
+      # Snapshot workflow appends .<run_number>-dev, so this tracks the next development patch after v2.1.2.
+      version: '2.1.3'
       # PR integration already runs the full multi-target test suite.
       run-tests: false
       nuget-source: 'https://www.hec.usace.army.mil/nexus/repository/consequences-nuget-public/'

CITATION.cff

@@ -2,8 +2,8 @@ cff-version: 1.2.0
 message: "If you use this software, please cite our article in the Journal of Open Source Software."
 type: software
 title: "Numerics: A .NET Library for Numerical Computing, Statistical Analysis, and Risk Assessment"
-version: "2.1.1"
-date-released: "2026-06-17"
+version: "2.1.2"
+date-released: "2026-07-09"
 license: 0BSD
 repository-code: "https://github.com/USACE-RMC/Numerics"
 url: "https://github.com/USACE-RMC/Numerics"

Numerics/Data/Statistics/RunningStatistics.cs

@@ -273,18 +273,39 @@ public void Push(IList<double> values)
                 Push(value);
         }
 
+        /// <summary>
+        /// Creates a copy of the running statistics.
+        /// </summary>
+        /// <returns>A new running statistics instance with the same accumulated state, independent of the original.</returns>
+        public RunningStatistics Clone()
+        {
+            return new RunningStatistics()
+            {
+                _n = _n,
+                _m1 = _m1,
+                _m2 = _m2,
+                _m3 = _m3,
+                _m4 = _m4,
+                _min = _min,
+                _max = _max
+            };
+        }
+
         /// <summary>
         /// Create a new running statistics over the combined samples of two existing running statistics.
         /// </summary>
+        /// <param name="a">The first running statistics.</param>
+        /// <param name="b">The second running statistics.</param>
+        /// <returns>A new running statistics instance, independent of both inputs.</returns>
         public static RunningStatistics Combine(RunningStatistics a, RunningStatistics b)
         {
             if (a._n == 0L)
             {
-                return b;
+                return b.Clone();
             }
             else if (b._n == 0L)
             {
-                return a;
+                return a.Clone();
             }
 
             long n = a._n + b._n;

Numerics/Data/Time Series/Support/Series.cs

@@ -125,12 +125,10 @@ public void Insert(int index, object? item)
         public virtual bool Remove(SeriesOrdinate<TIndex, TValue> item)
         {
             var index = IndexOf(item);
-            if (_seriesOrdinates.Remove(item) == true)
-            {
-                RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item, index));
-                return true;
-            }
-            return false;
+            if (index < 0) return false;
+            _seriesOrdinates.RemoveAt(index);
+            RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item, index));
+            return true;
         }
 
         /// <inheritdoc/>
@@ -144,23 +142,30 @@ public void Remove(object? item)
         }
 
         /// <inheritdoc/>
+        /// <remarks>
+        /// Removes the ordinate at the requested position directly, so when equal-valued
+        /// ordinates exist elsewhere in the series the element at <paramref name="index"/> is
+        /// the one removed and reported.
+        /// </remarks>
         public virtual void RemoveAt(int index)
         {
-            Remove(_seriesOrdinates[index]);
+            var item = _seriesOrdinates[index];
+            _seriesOrdinates.RemoveAt(index);
+            RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item, index));
         }
 
         /// <summary>
         /// Remove all elements from the collection.
         /// </summary>
+        /// <remarks>
+        /// Clears the backing list in one operation and raises a single reset event. The former
+        /// element-by-element removal cost two full equality scans per element, which made
+        /// clearing a large series O(n²).
+        /// </remarks>
         public void Clear()
         {
-            bool suppress = SuppressCollectionChanged;
-            SuppressCollectionChanged = true;
-            for (int i = _seriesOrdinates.Count - 1; i >= 0; i--)
-                Remove(_seriesOrdinates[i]);
-            SuppressCollectionChanged = false;
+            _seriesOrdinates.Clear();
             RaiseCollectionChangedReset();
-            SuppressCollectionChanged = suppress;
         }
 
         /// <inheritdoc/>