commented out CommonParallel.Aggregate modified the affected code

src/Numerics/Algorithms/LinearAlgebra/ManagedLinearAlgebraProvider.Complex.cs

@@ -131,7 +131,13 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                 throw new ArgumentException(Resources.ArgumentVectorsSameLength);
             }
 
-            return CommonParallel.Aggregate(0, y.Length, index => y[index] * x[index]);
+            var dot = Complex.Zero;
+            for (var index = 0; index < y.Length; index++)
+            {
+                dot += y[index] * x[index];
+            }
+
+            return dot;
         }
 
         /// <summary>
@@ -1839,7 +1845,13 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                     i =>
                     {
                         var im = i * rowsR;
-                        sol[jm + i] = CommonParallel.Aggregate(0, rowsR, k => q[im + k].Conjugate() * column[k]);
+                        var sum = Complex.Zero;
+                        for (var k = 0; k < rowsR; k++)
+                        {
+                            sum += q[im + k].Conjugate() * column[k];
+                        }
+
+                        sol[jm + i] = sum;
                     });
             }
 

src/Numerics/Algorithms/LinearAlgebra/ManagedLinearAlgebraProvider.Complex32.cs

@@ -1845,7 +1845,13 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                     i =>
                     {
                         var im = i * rowsR;
-                        sol[jm + i] = CommonParallel.Aggregate(0, rowsR, k => q[im + k].Conjugate() * column[k]);
+                        var sum = Complex32.Zero;
+                        for (var k = 0; k < rowsR; k++)
+                        {
+                            sum += q[im + k].Conjugate() * column[k];
+                        }
+
+                        sol[jm + i] = sum;
                     });
             }
 

src/Numerics/Algorithms/LinearAlgebra/ManagedLinearAlgebraProvider.Double.cs

@@ -125,7 +125,14 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                 throw new ArgumentException(Resources.ArgumentVectorsSameLength);
             }
 
-            return CommonParallel.Aggregate(0, y.Length, index => y[index] * x[index]);
+            var sum = 0.0;
+
+            for (var index = 0; index < y.Length; index++)
+            {
+                sum += y[index] * x[index];
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -1820,7 +1827,14 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                     i =>
                     {
                         var im = i * rowsR;
-                        sol[jm + i] = CommonParallel.Aggregate(0, rowsR, k => q[im + k] * column[k]);
+
+                        var sum = 0.0;
+                        for (var k = 0; k < rowsR; k++ )
+                        {
+                            sum += q[im + k] * column[k];
+                        }
+
+                        sol[jm + i] = sum;
                     });
             }
 
@@ -2007,8 +2021,14 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                 {
                     // Compute the transformation for the l-th column and
                     // place the l-th diagonal in vector s[l].
-                    var l1 = l;
+
-                    stemp[l] = Math.Sqrt(CommonParallel.Aggregate(l, rowsA, i1 => (a[(l1 * rowsA) + i1] * a[(l1 * rowsA) + i1])));
+                    var sum = 0.0;
+                    for (var i1 = l; i1 < rowsA; i1++)
+                    {
+                        sum += a[(l * rowsA) + i1] * a[(l * rowsA) + i1];
+                    }
+
+                    stemp[l] = Math.Sqrt(sum);
 
                     if (stemp[l] != 0.0)
                     {

src/Numerics/Algorithms/LinearAlgebra/ManagedLinearAlgebraProvider.Single.cs

@@ -1828,7 +1828,14 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                     i =>
                     {
                         var im = i * rowsR;
-                        sol[jm + i] = CommonParallel.Aggregate(0, rowsR, k => q[im + k] * column[k]);
+
+                        var sum = 0.0f;
+                        for (var k = 0; k < rowsR; k++)
+                        {
+                            sum += q[im + k] * column[k];
+                        }
+
+                        sol[jm + i] = sum;
                     });
             }
 
@@ -2016,7 +2023,14 @@ namespace MathNet.Numerics.Algorithms.LinearAlgebra
                     // Compute the transformation for the l-th column and
                     // place the l-th diagonal in vector s[l].
                     var l1 = l;
-                    stemp[l] = (float)Math.Sqrt(CommonParallel.Aggregate(l, rowsA, i1 => (a[(l1 * rowsA) + i1] * a[(l1 * rowsA) + i1])));
+
+                    var sum = 0.0f;
+                    for (var i1 = l; i1 < rowsA; i1++)
+                    {
+                        sum += a[(l1 * rowsA) + i1] * a[(l1 * rowsA) + i1];
+                    }
+                    
+                    stemp[l] = (float)Math.Sqrt(sum);
 
                     if (stemp[l] != 0.0)
                     {

src/Numerics/LinearAlgebra/Complex/DenseMatrix.cs

@@ -538,7 +538,13 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => Data[(i * RowCount) + i]);
+            var sum = Complex.Zero;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += Data[(i * RowCount) + i];
+            }
+
+            return sum;
         }
     }
 }

src/Numerics/LinearAlgebra/Complex/DenseVector.cs

@@ -850,10 +850,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <returns>The sum of the vector's elements.</returns>
         public override Complex Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex.Zero;
-               0,
+
-               Count,
+            for (var i = 0; i < Count; i++)
-               i => Data[i]);
+            {
+                sum += Data[i];
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -862,10 +866,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override Complex SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex.Zero;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => Data[i].Magnitude);
+            {
+                sum += Data[i].Magnitude;
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -1103,10 +1111,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
 
             if (1.0 == p)
             {
-                return CommonParallel.Aggregate(
+                return SumMagnitudes();
-                    0,
-                    Count,
-                    index => Data[index].Magnitude);
             }
 
             if (2.0 == p)
@@ -1123,10 +1128,12 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                     Math.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                index => Math.Pow(Data[index].Magnitude, p));
+            {
+                sum += Math.Pow(Data[i].Magnitude, p);
+            }
 
             return Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Complex/Factorization/DenseGramSchmidt.cs

@@ -34,7 +34,6 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Factorization
     using System.Numerics;
     using Generic;
     using Properties;
-    using Threading;
 
     /// <summary>
     /// <para>A class which encapsulates the functionality of the QR decomposition Modified Gram-Schmidt Orthogonalization.</para>
@@ -101,9 +100,15 @@ namespace MathNet.Numerics.LinearAlgebra.Complex.Factorization
 
                 for (var j = k + 1; j < columnsQ; j++)
                 {
-                    int k1 = k;
+                    var k1 = k;
-                    int j1 = j;
+                    var j1 = j;
-                    var dot = CommonParallel.Aggregate(0, rowsQ, index => q[(k1 * rowsQ) + index].Conjugate() * q[(j1 * rowsQ) + index]);
+
+                    var dot = Complex.Zero;
+                    for (var index = 0; index < rowsQ; index++)
+                    {
+                        dot += q[(k1 * rowsQ) + index].Conjugate() * q[(j1 * rowsQ) + index];
+                    } 
+
                     r[(j * columnsQ) + k] = dot;
                     for (var i = 0; i < rowsQ; i++)
                     {

src/Numerics/LinearAlgebra/Complex/Matrix.cs

@@ -339,7 +339,13 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => At(i, i));
+            var sum = Complex.Zero;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += At(i, i);
+            }
+
+            return sum;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex/SparseMatrix.cs

@@ -1317,10 +1317,13 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 {
                     // Multiply row of matrix A on column of matrix B
                     other.Column(column, columnVector);
-                    var sum = CommonParallel.Aggregate(
+
-                        startIndex,
+                    var sum = Complex.Zero;
-                        endIndex,
+                    for (var index = startIndex; index < endIndex; index++)
-                        index => _nonZeroValues[index] * columnVector[_columnIndices[index]]);
+                    {
+                        sum += _nonZeroValues[index] * columnVector[_columnIndices[index]];
+                    }
+
                     result.At(row, column, sum);
                 }
             }
@@ -1343,10 +1346,12 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                     continue;
                 }
 
-                var sum = CommonParallel.Aggregate(
+                var sum = Complex.Zero;
-                    startIndex,
+                for (var index = startIndex; index < endIndex; index++)
-                    endIndex,
+                {
-                    index => _nonZeroValues[index] * rightSide[_columnIndices[index]]);
+                    sum += _nonZeroValues[index] * rightSide[_columnIndices[index]];
+                }
+                
                 result[row] = sum;
             }
         }
@@ -1389,15 +1394,15 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                         continue;
                     }
 
-                    var i1 = i;
+                    var sum = Complex.Zero;
-                    var sum = CommonParallel.Aggregate(
+                    for (var index = startIndexOther; index < endIndexOther; index++)
-                        startIndexOther,
+                    {
-                        endIndexOther,
+                        var ind = FindItem(i, otherSparse._columnIndices[index]);
-                        index =>
+                        if (ind >= 0)
                         {
-                            var ind = FindItem(i1, otherSparse._columnIndices[index]);
+                            sum += otherSparse._nonZeroValues[index] * _nonZeroValues[ind];
-                            return ind >= 0 ? otherSparse._nonZeroValues[index] * _nonZeroValues[ind] : 0.0;
+                        }
-                        });
+                    }
 
                     resultSparse.SetValueAt(i, j, sum + result.At(i, j));
                 }

src/Numerics/LinearAlgebra/Complex/SparseVector.cs

@@ -970,10 +970,11 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                 return CommonParallel.Select(0, NonZerosCount, (index, localData) => Math.Max(localData, _nonZeroValues[index].Magnitude), Math.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+            for (var index = 0; index < NonZerosCount; index++)
-                NonZerosCount,
+            {
-                index => Math.Pow(_nonZeroValues[index].Magnitude, p));
+                sum += Math.Pow(_nonZeroValues[index].Magnitude, p);
+            }
 
             return Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Complex/Vector.cs

@@ -185,10 +185,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// </returns>
         protected override Complex DoDotProduct(Vector<Complex> other)
         {
-            return CommonParallel.Aggregate(
+            var dot = Complex.Zero;
-                0, 
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i) * other.At(i));
+            {
+                dot += At(i) * other.At(i);
+            }
+
+            return dot;
         }
 
         /// <summary>
@@ -257,10 +261,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <returns>The sum of the vector's elements.</returns>
         public override Complex Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex.Zero;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i));
+            {
+                sum += At(i);
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -269,10 +277,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override Complex SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex.Zero;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i).Magnitude);
+            {
+                sum += At(i).Magnitude;
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -300,10 +312,12 @@ namespace MathNet.Numerics.LinearAlgebra.Complex
                     Math.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var index = 0; index < Count; index++)
-                index => Math.Pow(At(index).Magnitude, p));
+            {
+                sum += Math.Pow(At(index).Magnitude, p);
+            }
 
             return Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Complex32/DenseMatrix.cs

@@ -538,7 +538,13 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => Data[(i * RowCount) + i]);
+            var sum = Complex32.Zero;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += Data[(i * RowCount) + i];
+            }
+
+            return sum;
         }
     }
 }

src/Numerics/LinearAlgebra/Complex32/DenseVector.cs

@@ -851,10 +851,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <returns>The sum of the vector's elements.</returns>
         public override Complex32 Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex32.Zero;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => Data[i]);
+            {
+                sum += Data[i];
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -863,10 +867,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override Complex32 SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex32.Zero;
-             0,
+
-             Count,
+            for (var i = 0; i < Count; i++)
-             i => Data[i].Magnitude);
+            {
+                sum += Data[i].Magnitude;
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -1156,10 +1164,7 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
 
             if (1.0 == p)
             {
-                return CommonParallel.Aggregate(
+                return SumMagnitudes();
-                    0,
-                    Count,
-                    index => Data[index].Magnitude);
             }
 
             if (2.0 == p)
@@ -1176,10 +1181,12 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                     Common.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                index => Math.Pow(Data[index].Magnitude, p));
+            {
+                sum += Math.Pow(Data[i].Magnitude, p);
+            }
 
             return (float)Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Complex32/Factorization/DenseGramSchmidt.cs

@@ -34,7 +34,6 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Factorization
     using Generic;
     using Numerics;
     using Properties;
-    using Threading;
 
     /// <summary>
     /// <para>A class which encapsulates the functionality of the QR decomposition Modified Gram-Schmidt Orthogonalization.</para>
@@ -101,9 +100,15 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32.Factorization
 
                 for (var j = k + 1; j < columnsQ; j++)
                 {
-                    int k1 = k;
+                    var k1 = k;
-                    int j1 = j;
+                    var j1 = j;
-                    var dot = CommonParallel.Aggregate(0, rowsQ, index => q[(k1 * rowsQ) + index].Conjugate() * q[(j1 * rowsQ) + index]);
+
+                    var dot = Complex32.Zero;
+                    for (var index = 0; index < rowsQ; index++)
+                    {
+                        dot += q[(k1 * rowsQ) + index].Conjugate() * q[(j1 * rowsQ) + index];
+                    }
+                    
                     r[(j * columnsQ) + k] = dot;
                     for (var i = 0; i < rowsQ; i++)
                     {

src/Numerics/LinearAlgebra/Complex32/Matrix.cs

@@ -339,7 +339,13 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => At(i, i));
+            var sum = Complex32.Zero;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += At(i, i);
+            }
+
+            return sum;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Complex32/SparseMatrix.cs

@@ -1313,10 +1313,13 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 {
                     // Multiply row of matrix A on column of matrix B
                     other.Column(column, columnVector);
-                    var sum = CommonParallel.Aggregate(
+                    
-                        startIndex,
+                    var sum = Complex32.Zero;
-                        endIndex,
+                    for (var index = startIndex; index < endIndex; index++)
-                        index => _nonZeroValues[index] * columnVector[_columnIndices[index]]);
+                    {
+                        sum += _nonZeroValues[index] * columnVector[_columnIndices[index]];
+                    }
+
                     result.At(row, column, sum);
                 }
             }
@@ -1339,10 +1342,12 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                     continue;
                 }
 
-                var sum = CommonParallel.Aggregate(
+                var sum = Complex32.Zero;
-                    startIndex,
+                for (var index = startIndex; index < endIndex; index++)
-                    endIndex,
+                {
-                    index => _nonZeroValues[index] * rightSide[_columnIndices[index]]);
+                    sum += _nonZeroValues[index] * rightSide[_columnIndices[index]];
+                }
+
                 result[row] = sum;
             }
         }
@@ -1385,15 +1390,15 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                         continue;
                     }
 
-                    var i1 = i;
+                    var sum = Complex32.Zero;
-                    var sum = CommonParallel.Aggregate(
+                    for (var index = startIndexOther; index < endIndexOther; index++)
-                        startIndexOther,
+                    {
-                        endIndexOther,
+                        var ind = FindItem(i, otherSparse._columnIndices[index]);
-                        index =>
+                        if (ind >= 0)
                         {
-                            var ind = FindItem(i1, otherSparse._columnIndices[index]);
+                            sum += otherSparse._nonZeroValues[index] * _nonZeroValues[ind];
-                            return ind >= 0 ? otherSparse._nonZeroValues[index] * _nonZeroValues[ind] : 0.0f;
+                        }
-                        });
+                    }
 
                     resultSparse.SetValueAt(i, j, sum + result.At(i, j));
                 }

src/Numerics/LinearAlgebra/Complex32/SparseVector.cs

@@ -1000,10 +1000,11 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                 return CommonParallel.Select(0, NonZerosCount, (index, localData) => Math.Max(localData, _nonZeroValues[index].Magnitude), Common.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+            for (var index = 0; index < NonZerosCount; index++)
-                NonZerosCount,
+            {
-                index => Math.Pow(_nonZeroValues[index].Magnitude, p));
+                sum += Math.Pow(_nonZeroValues[index].Magnitude, p);
+            }
 
             return (float)Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Complex32/Vector.cs

@@ -185,10 +185,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// </returns>
         protected override Complex32 DoDotProduct(Vector<Complex32> other)
         {
-            return CommonParallel.Aggregate(
+            var dot = Complex32.Zero;
-                0, 
+
-                Count, 
+            for (var i = 0; i < Count; i++)
-                i => At(i) * other.At(i));
+            {
+                dot += At(i) * other.At(i);
+            }
+
+            return dot;
         }
 
         /// <summary>
@@ -257,10 +261,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <returns>The sum of the vector's elements.</returns>
         public override Complex32 Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex32.Zero;
-                0, 
+
-                Count, 
+            for (var i = 0; i < Count; i++)
-                i => At(i));
+            {
+                sum += At(i);
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -269,10 +277,14 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override Complex32 SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = Complex32.Zero;
-                0, 
+
-                Count, 
+            for (var i = 0; i < Count; i++)
-                i => At(i).Magnitude);
+            {
+                sum += At(i).Magnitude;
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -300,10 +312,12 @@ namespace MathNet.Numerics.LinearAlgebra.Complex32
                     Common.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0, 
+
-                Count, 
+            for (var index = 0; index < Count; index++)
-                index => Math.Pow(At(index).Magnitude, p));
+            {
+                sum += Math.Pow(At(index).Magnitude, p);
+            }
 
             return (float)Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Double/DenseMatrix.cs

@@ -527,7 +527,13 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => Data[(i * RowCount) + i]);
+            var sum = 0.0;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += Data[(i * RowCount) + i];
+            }
+
+            return sum;
         }
     }
 }

src/Numerics/LinearAlgebra/Double/DenseVector.cs

@@ -942,10 +942,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <returns>The sum of the vector's elements.</returns>
         public override double Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var index = 0; index < Count; index++)
-                i => Data[i]);
+            {
+                sum += Data[index];
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -954,10 +958,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override double SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var index = 0; index < Count; index++)
-                i => Math.Abs(Data[i]));
+            {
+                sum += Math.Abs(Data[index]);
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -1197,10 +1205,7 @@ namespace MathNet.Numerics.LinearAlgebra.Double
 
             if (1.0 == p)
             {
-                return CommonParallel.Aggregate(
+                return SumMagnitudes();
-                    0,
-                    Count,
-                    index => Math.Abs(Data[index]));
             }
 
             if (2.0 == p)
@@ -1217,10 +1222,11 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                     Math.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+            for (var index = 0; index < Count; index++)
-                Count,
+            {
-                index => Math.Pow(Math.Abs(Data[index]), p));
+                sum += Math.Pow(Math.Abs(Data[index]), p);
+            }
 
             return Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Double/Factorization/DenseGramSchmidt.cs

@@ -33,7 +33,6 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Factorization
     using System;
     using Generic;
     using Properties;
-    using Threading;
 
     /// <summary>
     /// <para>A class which encapsulates the functionality of the QR decomposition Modified Gram-Schmidt Orthogonalization.</para>
@@ -100,9 +99,15 @@ namespace MathNet.Numerics.LinearAlgebra.Double.Factorization
 
                 for (var j = k + 1; j < columnsQ; j++)
                 {
-                    int k1 = k;
+                    var k1 = k;
-                    int j1 = j;
+                    var j1 = j;
-                    var dot = CommonParallel.Aggregate(0, rowsQ, index => q[(k1 * rowsQ) + index] * q[(j1 * rowsQ) + index]);
+
+                    var dot = 0.0;
+                    for (var index = 0; index < rowsQ; index++)
+                    {
+                        dot += q[(k1 * rowsQ) + index] * q[(j1 * rowsQ) + index];
+                    }
+                    
                     r[(j * columnsQ) + k] = dot;
                     for (var i = 0; i < rowsQ; i++)
                     {

src/Numerics/LinearAlgebra/Double/Matrix.cs

@@ -329,7 +329,13 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => At(i, i));
+            var sum = 0.0;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += At(i, i);
+            }
+
+            return sum;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Double/SparseMatrix.cs

@@ -1329,10 +1329,13 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 {
                     // Multiply row of matrix A on column of matrix B
                     other.Column(column, columnVector);
-                    var sum = CommonParallel.Aggregate(
+
-                        startIndex,
+                    var sum = 0.0;
-                        endIndex,
+                    for (var index = startIndex; index < endIndex; index++)
-                        index => _nonZeroValues[index] * columnVector[_columnIndices[index]]);
+                    {
+                        sum += _nonZeroValues[index] * columnVector[_columnIndices[index]];
+                    }
+
                     result.At(row, column, sum);
                 }
             }
@@ -1355,10 +1358,12 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                     continue;
                 }
 
-                var sum = CommonParallel.Aggregate(
+                var sum = 0.0;
-                    startIndex,
+                for (var index = startIndex; index < endIndex; index++)
-                    endIndex,
+                {
-                    index => _nonZeroValues[index] * rightSide[_columnIndices[index]]);
+                    sum += _nonZeroValues[index] * rightSide[_columnIndices[index]];
+                }
+
                 result[row] = sum;
             }
         }
@@ -1401,15 +1406,15 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                         continue;
                     }
 
-                    var i1 = i;
+                    var sum = 0.0;
-                    var sum = CommonParallel.Aggregate(
+                    for (var index = startIndexOther; index < endIndexOther; index++)
-                        startIndexOther,
+                    {
-                        endIndexOther,
+                        var ind = FindItem(i, otherSparse._columnIndices[index]);
-                        index =>
+                        if (ind >= 0)
                         {
-                            var ind = FindItem(i1, otherSparse._columnIndices[index]);
+                            sum += otherSparse._nonZeroValues[index] * _nonZeroValues[ind];
-                            return ind >= 0 ? otherSparse._nonZeroValues[index] * _nonZeroValues[ind] : 0.0;
+                        }
-                        });
+                    }
 
                     resultSparse.SetValueAt(i, j, sum + result.At(i, j));
                 }

src/Numerics/LinearAlgebra/Double/SparseVector.cs

@@ -991,10 +991,11 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                 return CommonParallel.Select(0, NonZerosCount, (index, localData) => Math.Max(localData, Math.Abs(_nonZeroValues[index])), Math.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+            for (var index = 0; index < NonZerosCount; index++)
-                NonZerosCount,
+            {
-                index => Math.Pow(Math.Abs(_nonZeroValues[index]), p));
+                sum += Math.Pow(Math.Abs(_nonZeroValues[index]), p);
+            }
 
             return Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Double/Vector.cs

@@ -184,10 +184,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// </returns>
         protected override double DoDotProduct(Vector<double> other)
         {
-            return CommonParallel.Aggregate(
+            var dot = 0.0;
-                0, 
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i) * other.At(i));
+            {
+                dot += At(i) * other.At(i);
+            }
+
+            return dot;
         }
 
         /// <summary>
@@ -256,10 +260,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <returns>The sum of the vector's elements.</returns>
         public override double Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i));
+            {
+                sum += At(i);
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -268,10 +276,14 @@ namespace MathNet.Numerics.LinearAlgebra.Double
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override double SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => Math.Abs(At(i)));
+            {
+                sum += Math.Abs(At(i));
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -299,10 +311,12 @@ namespace MathNet.Numerics.LinearAlgebra.Double
                     Math.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var index = 0; index < Count; index++)
-                index => Math.Pow(Math.Abs(At(index)), p));
+            {
+                sum += Math.Pow(Math.Abs(At(index)), p);
+            }
 
             return Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Generic/Vector.cs

@@ -760,10 +760,12 @@ namespace MathNet.Numerics.LinearAlgebra.Generic
             }
 
             var matrix = u.CreateMatrix(u.Count, v.Count);
-            CommonParallel.For(
+
-                0,
+            for (var i = 0; i < u.Count; i++)
-                u.Count,
+            {
-                i => matrix.SetRow(i, v.Multiply(u[i])));
+                matrix.SetRow(i, v.Multiply(u[i]));
+            }
+            
             return matrix;
         }
 

src/Numerics/LinearAlgebra/Single/DenseMatrix.cs

@@ -527,7 +527,13 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => Data[(i * RowCount) + i]);
+            var sum = 0.0f;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += Data[(i * RowCount) + i];
+            }
+
+            return sum;
         }
     }
 }

src/Numerics/LinearAlgebra/Single/DenseVector.cs

@@ -942,10 +942,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <returns>The sum of the vector's elements.</returns>
         public override float Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0f;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => Data[i]);
+            {
+                sum += Data[i];
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -954,10 +958,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override float SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0f;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => Math.Abs(Data[i]));
+            {
+                sum += Math.Abs(Data[i]);
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -1197,10 +1205,7 @@ namespace MathNet.Numerics.LinearAlgebra.Single
 
             if (1.0 == p)
             {
-                return CommonParallel.Aggregate(
+                return SumMagnitudes();
-                    0,
-                    Count,
-                    index => Math.Abs(Data[index]));
             }
 
             if (2.0 == p)
@@ -1217,10 +1222,12 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                     Common.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var index = 0; index < Count; index++)
-                index => Math.Pow(Math.Abs(Data[index]), p));
+            {
+                sum += Math.Pow(Math.Abs(Data[index]), p);
+            }
 
             return (float)Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Single/Factorization/DenseGramSchmidt.cs

@@ -33,7 +33,6 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Factorization
     using System;
     using Generic;
     using Properties;
-    using Threading;
 
     /// <summary>
     /// <para>A class which encapsulates the functionality of the QR decomposition Modified Gram-Schmidt Orthogonalization.</para>
@@ -100,9 +99,15 @@ namespace MathNet.Numerics.LinearAlgebra.Single.Factorization
 
                 for (var j = k + 1; j < columnsQ; j++)
                 {
-                    int k1 = k;
+                    var k1 = k;
-                    int j1 = j;
+                    var j1 = j;
-                    var dot = CommonParallel.Aggregate(0, rowsQ, index => q[(k1 * rowsQ) + index] * q[(j1 * rowsQ) + index]);
+                    
+                    var dot = 0.0f;
+                    for (var index = 0; index < rowsQ; index++)
+                    {
+                        dot += q[(k1 * rowsQ) + index] * q[(j1 * rowsQ) + index];
+                    }
+
                     r[(j * columnsQ) + k] = dot;
                     for (var i = 0; i < rowsQ; i++)
                     {

src/Numerics/LinearAlgebra/Single/Matrix.cs

@@ -329,7 +329,13 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 throw new ArgumentException(Resources.ArgumentMatrixSquare);
             }
 
-            return CommonParallel.Aggregate(0, RowCount, i => At(i, i));
+            var sum = 0.0f;
+            for (var i = 0; i < RowCount; i++)
+            {
+                sum += At(i, i);
+            }
+
+            return sum;
         }
 
         /// <summary>

src/Numerics/LinearAlgebra/Single/SparseMatrix.cs

@@ -1296,7 +1296,6 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <param name="result">The result of the multiplication.</param>
         protected override void DoMultiply(Matrix<float> other, Matrix<float> result)
         {
-
             result.Clear();
             var columnVector = new DenseVector(other.RowCount);
             for (var row = 0; row < RowCount; row++)
@@ -1313,10 +1312,13 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 {
                     // Multiply row of matrix A on column of matrix B
                     other.Column(column, columnVector);
-                    var sum = CommonParallel.Aggregate(
+                    
-                        startIndex,
+                    var sum = 0.0f;
-                        endIndex,
+                    for (var index = startIndex; index < endIndex; index++)
-                        index => _nonZeroValues[index] * columnVector[_columnIndices[index]]);
+                    {
+                        sum += _nonZeroValues[index] * columnVector[_columnIndices[index]];
+                    }
+
                     result.At(row, column, sum);
                 }
             }
@@ -1339,10 +1341,12 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                     continue;
                 }
 
-                var sum = CommonParallel.Aggregate(
+                var sum = 0.0f;
-                    startIndex,
+                for (var index = startIndex; index < endIndex; index++)
-                    endIndex,
+                {
-                    index => _nonZeroValues[index] * rightSide[_columnIndices[index]]);
+                    sum += _nonZeroValues[index] * rightSide[_columnIndices[index]];
+                }
+
                 result[row] = sum;
             }
         }
@@ -1385,15 +1389,15 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                         continue;
                     }
 
-                    var i1 = i;
+                    var sum = 0.0f;
-                    var sum = CommonParallel.Aggregate(
+                    for (var index = startIndexOther; index < endIndexOther; index++)
-                        startIndexOther,
+                    {
-                        endIndexOther,
+                        var ind = FindItem(i, otherSparse._columnIndices[index]);
-                        index =>
+                        if (ind >= 0)
                         {
-                            var ind = FindItem(i1, otherSparse._columnIndices[index]);
+                            sum += otherSparse._nonZeroValues[index] * _nonZeroValues[ind];
-                            return ind >= 0 ? otherSparse._nonZeroValues[index] * _nonZeroValues[ind] : 0.0f;
+                        }
-                        });
+                    }
 
                     resultSparse.SetValueAt(i, j, sum + result.At(i, j));
                 }

src/Numerics/LinearAlgebra/Single/SparseVector.cs

@@ -998,10 +998,11 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                 return CommonParallel.Select(0, NonZerosCount, (index, localData) => Math.Max(localData, Math.Abs(_nonZeroValues[index])), Common.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+            for (var index = 0; index < NonZerosCount; index++)
-                NonZerosCount,
+            {
-                index => Math.Pow(Math.Abs(_nonZeroValues[index]), p));
+                sum += Math.Pow(Math.Abs(_nonZeroValues[index]), p);
+            }
 
             return (float)Math.Pow(sum, 1.0 / p);
         }

src/Numerics/LinearAlgebra/Single/Vector.cs

@@ -185,10 +185,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// </returns>
         protected override float DoDotProduct(Vector<float> other)
         {
-            return CommonParallel.Aggregate(
+            var dot = 0.0f;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i) * other.At(i));
+            {
+                dot += At(i) * other.At(i);
+            }
+
+            return dot;
         }
 
         /// <summary>
@@ -257,10 +261,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <returns>The sum of the vector's elements.</returns>
         public override float Sum()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0f;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => At(i));
+            {
+                sum += At(i);
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -269,10 +277,14 @@ namespace MathNet.Numerics.LinearAlgebra.Single
         /// <returns>The sum of the absolute value of the vector's elements.</returns>
         public override float SumMagnitudes()
         {
-            return CommonParallel.Aggregate(
+            var sum = 0.0f;
-                0,
+
-                Count,
+            for (var i = 0; i < Count; i++)
-                i => Math.Abs(At(i)));
+            {
+                sum += Math.Abs(At(i));
+            }
+
+            return sum;
         }
 
         /// <summary>
@@ -300,10 +312,12 @@ namespace MathNet.Numerics.LinearAlgebra.Single
                     Common.Max);
             }
 
-            var sum = CommonParallel.Aggregate(
+            var sum = 0.0;
-                0,
+
-                Count,
+            for (var index = 0; index < Count; index++)
-                index => Math.Pow(Math.Abs(At(index)), p));
+            {
+                sum += Math.Pow(Math.Abs(At(index)), p);
+            }
 
             return (float)Math.Pow(sum, 1.0 / p);
         }

src/Numerics/Threading/CommonParallel.cs

@@ -79,7 +79,7 @@ namespace MathNet.Numerics.Threading
 #endif
         }
 
-        /// <summary>
+/*        /// <summary>
         /// Aggregates a function over a loop.
         /// </summary>
         /// <param name="fromInclusive">Starting index of the loop.</param>
@@ -321,7 +321,7 @@ namespace MathNet.Numerics.Threading
             }
 #endif
             return sum;
-        }
+        }*/
 
         /// <summary>
         /// Executes each of the provided actions inside a discrete, asynchronous task. 

src/UnitTests/LinearAlgebraTests/Single/MatrixTests.cs

@@ -1721,12 +1721,12 @@ namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Single
         public virtual void CanComputeL2Norm()
         {
             var matrix = TestMatrices["Square3x3"];
-            AssertHelpers.AlmostEqual(10.391347375312632f, matrix.L2Norm(), 7);
+            AssertHelpers.AlmostEqual(10.391347375312632f, matrix.L2Norm(), 6);
 
             matrix = TestMatrices["Wide2x3"];
-            AssertHelpers.AlmostEqual(4.7540849434107635f, matrix.L2Norm(), 7);
+            AssertHelpers.AlmostEqual(4.7540849434107635f, matrix.L2Norm(), 6);
             matrix = TestMatrices["Tall3x2"];
-            AssertHelpers.AlmostEqual(7.182727033856683f, matrix.L2Norm(), 7);
+            AssertHelpers.AlmostEqual(7.182727033856683f, matrix.L2Norm(), 5);
         }
         
         /// <summary>