Fixed all bugs on Vector and DenseVector for the new functional friendly interface.

src/Numerics/LinearAlgebra/Double/DenseVector.cs

@@ -595,8 +595,20 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
             else
             {
-                CopyTo(result);
-                result.Subtract(other);
+                var rdense = result as DenseVector;
+                var odense = other as DenseVector;
+                if (rdense != null && odense != null)
+                {
+                    CopyTo(result);
+                    Control.LinearAlgebraProvider.AddVectorToScaledVector(rdense.Data, -1.0, odense.Data);
+                }
+                else
+                {
+                    CommonParallel.For(
+                        0,
+                        Data.Length,
+                        index => result[index] = this.Data[index] - other[index]);
+                }
             }
         }
 
@@ -641,9 +653,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 throw new ArgumentException(Resources.ArgumentVectorsSameLength, "rightSide");
             }
 
-            var ret = leftSide.Clone();
-            ret.Subtract(rightSide);
-            return ret;
+            return leftSide.Subtract(rightSide);
         }
 
         /// <summary>
@@ -722,9 +732,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 throw new ArgumentNullException("leftSide");
             }
 
-            var ret = (DenseVector)leftSide.Clone();
-            ret.Multiply(rightSide);
-            return ret;
+            return (DenseVector) leftSide.Multiply(rightSide);
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Double/Vector.cs

@@ -261,8 +261,10 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
             else
             {
-                CopyTo(result);
-                result.Add(other);
+                CommonParallel.For(
+                    0,
+                    Count,
+                    index => result[index] = this[index] + other[index]);
             }
         }
 
@@ -408,14 +410,16 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
             if (ReferenceEquals(this, result) || ReferenceEquals(other, result))
             {
-                var tmp = result.CreateVector(result.Count);
-                Subtract(other, tmp);
+                var tmp = Subtract(other);
                 tmp.CopyTo(result);
             }
             else
             {
                 CopyTo(result);
-                result.Subtract(other);
+                CommonParallel.For(
+                    0,
+                    Count,
+                    index => result[index] = this[index] - other[index]);
             }
         }
 
@@ -635,11 +639,10 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
             else
             {
-                CopyTo(result);
                 CommonParallel.For(
                     0,
                     Count,
-                    index => result[index] *= other[index]);
+                    index => result[index] = this[index] * other[index]);
             }
         }
 
@@ -708,11 +711,10 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
             else
             {
-                CopyTo(result);
                 CommonParallel.For(
                     0,
                     Count,
-                    index => result[index] /= other[index]);
+                    index => result[index] = this[index] / other[index]);
             }
         }
 
@@ -1190,13 +1192,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
             }
 
             var norm = Norm(p);
-            var clone = Clone();
+            var clone = this.Clone();
             if (norm == 0.0)
             {
                 return clone;
             }
 
-            clone.Multiply(1.0 / norm);
+            clone.Multiply(1.0 / norm, clone);
+
             return clone;
         }
 

src/UnitTests/LinearAlgebraTests/Double/DenseVectorTests.cs

@@ -153,7 +153,10 @@ namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Double
         {
             var vector = new DenseVector(this._data);
             var other = +vector;
-            Assert.AreSame(vector, other, "Should be the same vector");
+            for (var i = 0; i < this._data.Length; i++)
+            {
+                Assert.AreEqual(vector[i], other[i]);
+            }
         }
 
         [Test]