matrix<double> operator == performs false on identical matrices

[Anatom70]

I create an int random symmetrical matrix and calculate the transposed matrix, which should be identical.
The matrix == operator compiles, but performs false on comparison,
An extended method, which compares the matrices element by element performs true

[jkalias]

Can you please provide a code snippet which demonstrates this behavior?

[Anatom70]

Hello! The issue occurs with 12x12 matrices filled with random numbers[-100,100] and is not reproducible. I build a symmetrical matrix, transpose it and compare it with the original. The behavior disappears when I check for deviations > 1E-10 overriding the == operator. Regards, Thomas Von: jkalias ***@***.***> Gesendet: Samstag, 28. September 2024 13:21 An: mathnet/mathnet-numerics ***@***.***> Cc: Anatom70 ***@***.***>; Author ***@***.***> Betreff: Re: [mathnet/mathnet-numerics] matrix<double> operator == performs false on identical matrices (Issue #1089) Can you please provide a code snippet which demonstrates this behavior? — Reply to this email directly, view it on GitHub <#1089 (comment)> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/BKT7QJ2FP32PUGT23AD5OYDZY2GJFAVCNFSM6AAAAABMXODXA2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDGOBQGYYDOMRZGQ> . You are receiving this because you authored the thread. <https://github.com/notifications/beacon/BKT7QJ7VDWRGWUMHPLRIOULZY2GJFA5CNFSM6AAAAABMXODXA2WGG33NNVSW45C7OR4XAZNMJFZXG5LFINXW23LFNZ2KUY3PNVWWK3TUL5UWJTUN4UXT4.gif> Message ID: ***@***.*** ***@***.***> >

[jkalias]

What do you mean it's not reproducible?
Can you provide a code snippet for this 12x12 matrix? Or at bare minimum print out the matrix for which this happens, otherwise the bug can't be fixed.

[Anatom70]

Name Wert Typ ▶ $exception {"Fehler bei \"Assert.IsTrue\". "} Microsoft.VisualStudio.TestTools.UnitTesting.AssertFailedException ◢ this {UnitTest1.UnitTest_Quadratical_Matrices} UnitTest1.UnitTest_Quadratical_Matrices matrixDimension 30 int ◢ randomGeneratorDimension {RiosEngineering.Mathematics.Statistics.RandomGenerator} RiosEngineering.Mathematics.Statistics.RandomGenerator ▶ csp {System.Security.Cryptography.RNGCryptoServiceProvider} System.Security.Cryptography.RNGCryptoServiceProvider ▶ range {int[2]} int[] ▶ Statische Member i 0 int ◢ symmetricMatrix {RiosEngineering.Mathematics.LinearAlgebra.MatrixGenerator} RiosEngineering.Mathematics.LinearAlgebra.MatrixGenerator ▶ Matrix DenseMatrix 30x30-Double MathNet.Numerics.LinearAlgebra.Matrix<double> {MathNet.Numerics.LinearAlgebra.Double.DenseMatrix} ▶ randomGenerator {RiosEngineering.Mathematics.Statistics.RandomGenerator} RiosEngineering.Mathematics.Statistics.RandomGenerator ◢ eigen {MathNet.Numerics.LinearAlgebra.Double.Factorization.DenseEvd} MathNet.Numerics.LinearAlgebra.Factorization.Evd<double> {MathNet.Numerics.LinearAlgebra.Double.Factorization.DenseEvd} ▶ D DenseMatrix 30x30-Double MathNet.Numerics.LinearAlgebra.Matrix<double> {MathNet.Numerics.LinearAlgebra.Double.DenseMatrix} Determinant 1.0072948434831587E+69 double ▶ EigenValues DenseVector 30-Complex MathNet.Numerics.LinearAlgebra.Vector<System.Numerics.Complex> {MathNet.Numerics.LinearAlgebra.Complex.DenseVector} ▶ EigenVectors DenseMatrix 30x30-Double MathNet.Numerics.LinearAlgebra.Matrix<double> {MathNet.Numerics.LinearAlgebra.Double.DenseMatrix} IsFullRank true bool IsSymmetric true bool Rank 30 int ◢ transposedMatrix DenseMatrix 30x30-Double MathNet.Numerics.LinearAlgebra.Matrix<double> {MathNet.Numerics.LinearAlgebra.Double.DenseMatrix} ColumnCount 30 int RowCount 30 int ▶ Storage {MathNet.Numerics.LinearAlgebra.Storage.DenseColumnMajorMatrixStorage<double>} MathNet.Numerics.LinearAlgebra.Storage.MatrixStorage<double> {MathNet.Numerics.LinearAlgebra.Storage.DenseColumnMajorMatrixStorage<double>} ▶ Values {double[900]} double[] ▶ Statische Member ▶ Nicht öffentliche Member areEqual false bool ▶ eigenvector DenseVector 30-Complex MathNet.Numerics.LinearAlgebra.Vector<System.Numerics.Complex> {MathNet.Numerics.LinearAlgebra.Complex.DenseVector} index 30 int 9 -75 -56 -19 -85 77 83 69 -6 26 64 -68 38 .. 4 24

…

-75 -51 -85 -19 -45 -51 -15 -58 98 -85 23 -25 22 .. 90 72

-56 -85 -17 -76 -1 56 79 -61 -5 71 47 48 -89 .. -3 90

-19 -19 -76 -35 95 -7 35 -62 -72 9 76 2 58 .. 67 76

-85 -45 -1 95 -43 -73 64 -87 -10 98 -36 90 -81 .. 37 -57 77 -51 56 -7 -73 55 -77 -4 77 -17 40 87 86 .. 87 70 83 -15 79 35 64 -77 26 -80 57 -70 -21 -7 -40 .. -2 -31 69 -58 -61 -62 -87 -4 -80 71 72 -12 -76 37 17 .. -34 -21 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 50 -93 50 -77 0 9 13 28 -37 84 82 -40 68 .. -86 -58

-34 -88 -76 -30 -96 -69 17 59 99 61 0 -60 90 .. -89 -85 4 90 -3 67 37 87 -2 -34 -98 -22 31 25 -46 .. -54 -63 24 72 90 76 -57 70 -31 -21 99 44 -28 15 33 .. -63 -46 "testhost.exe" (CLR v4.0.30319: TestSourceHost: Enumerating source "C:\Program Files\Microsoft Visual Studio\2022\Professional\Common7\IDE\Extensions\TestPlatform\Microsoft.TestPlatform.CoreUtilities.dll" geladen. Das Laden von Symbolen wurde übersprungen. Das Modul ist optimiert, und die Debugoption "Nur eigenen Code" ist aktiviert. 9 -75 -56 -19 -85 77 83 69 -6 26 64 -68 38 .. 4 24

-75 -51 -85 -19 -45 -51 -15 -58 98 -85 23 -25 22 .. 90 72

-56 -85 -17 -76 -1 56 79 -61 -5 71 47 48 -89 .. -3 90

-19 -19 -76 -35 95 -7 35 -62 -72 9 76 2 58 .. 67 76

-85 -45 -1 95 -43 -73 64 -87 -10 98 -36 90 -81 .. 37 -57 77 -51 56 -7 -73 55 -77 -4 77 -17 40 87 86 .. 87 70 83 -15 79 35 64 -77 26 -80 57 -70 -21 -7 -40 .. -2 -31 69 -58 -61 -62 -87 -4 -80 71 72 -12 -76 37 17 .. -34 -21 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 50 -93 50 -77 0 9 13 28 -37 84 82 -40 68 .. -86 -58

-34 -88 -76 -30 -96 -69 17 59 99 61 0 -60 90 .. -89 -85 4 90 -3 67 37 87 -2 -34 -98 -22 31 25 -46 .. -54 -63 24 72 90 76 -57 70 -31 -21 99 44 -28 15 33 .. -63 -46 Microsoft.VisualStudio.TestTools.UnitTesting.AssertFailedException HResult=0x80131500 Nachricht = Fehler bei "Assert.IsTrue". Quelle = Microsoft.VisualStudio.TestPlatform.TestFramework Stapelüberwachung: bei Microsoft.VisualStudio.TestTools.UnitTesting.Assert.HandleFail(String assertionName, String message, Object[] parameters) bei Microsoft.VisualStudio.TestTools.UnitTesting.Assert.IsTrue(Boolean condition) bei UnitTest1.UnitTest_Quadratical_Matrices.Test_SymmetricMatrix() in C:\Software\Entwicklung\Mathematics\LinearAlgebra\MatrixGenerator\UnitTest1\UnitTest_Quadratical_Matrices.cs: Zeile78 [TestMethod] public void Test_SymmetricMatrix() { for (int i = 0; i < 95; i++) { MatrixGenerator symmetricMatrix = new MatrixGenerator(MatrixGenerator.Types.Symmetric, matrixDimension); Trace.WriteLine(symmetricMatrix.Matrix.ToMatrixString()); symmetricMatrix.Matrix.CheckElements(CheckSymmetry); Evd<double> eigen = symmetricMatrix.Matrix.Evd(); var eigenvector = eigen.EigenValues; int index = 0; eigenvector.ToList().ForEach(delegate (Complex eigenWert) { Assert.AreEqual(0, eigenvector[index].Imaginary, eigenvector[index].ToString() + " hat Imaginärteil !"); //Assert.AreEqual(eigenWerteNominal[index], eigenvector[index].Real, delta); index++; }); var transposedMatrix = symmetricMatrix.Matrix.Transpose(); Trace.WriteLine(transposedMatrix.ToMatrixString()); //bool areEqual = symmetricMatrix.Matrix.IsEqualTo(transposedMatrix); bool areEqual = symmetricMatrix.Matrix==transposedMatrix; Assert.IsTrue(areEqual); } } public class MatrixGenerator { readonly RandomGenerator randomGenerator = new RandomGenerator(-100, 100); public enum Types { Zero, Identity, Normal, UpperTriangel, LowerTriangel, Symmetric, SkewSymmetric } /// <summary> /// Access to the matrix instance /// </summary> public Matrix<double> Matrix { get; private set; } public MatrixGenerator(Types type, int rowCount, int colCount = -1) { int columnCount = Math.Max(rowCount, colCount); switch (type) { case Types.Zero: Matrix = Matrix<double>.Build.Dense(rowCount, columnCount); break; case Types.Identity: Matrix = Matrix<double>.Build.DenseIdentity(rowCount, columnCount); break; case Types.Normal: Matrix = Matrix<double>.Build.Dense(rowCount, columnCount); FillRandomElements(type); break; case Types.UpperTriangel: Matrix = Matrix<double>.Build.Dense(rowCount, columnCount, BuildUpperTriangelMatrix); break; case Types.LowerTriangel: Matrix = Matrix<double>.Build.Dense(rowCount, columnCount, BuildLowerTriangelMatrix); break; case Types.Symmetric: Matrix = Matrix<double>.Build.Dense(rowCount, columnCount); FillRandomElements(type); break; case Types.SkewSymmetric: Matrix = Matrix<double>.Build.Dense(rowCount, columnCount); FillRandomElements(type); break; default: break; } } private void FillRandomElements(Types type) { for (int i = 0; i < Matrix.RowCount; i++) { for (int j = 0; j < Matrix.ColumnCount; j++) { var value = randomGenerator.Next(); Matrix[i, j] = value; if (type > Types.Normal) { if (i == j) // Diagonale ? { if (type == Types.SkewSymmetric) { Matrix[i, j] = 0; } } else { Matrix[j, i] = (type == Types.SkewSymmetric) ? -value : value; } } } // next j } // next i } // end FillRandomElements private double BuildLowerTriangelMatrix(int row, int col) { if (row < col) { return 0; } else { return randomGenerator.Next(); } } private double BuildUpperTriangelMatrix(int row, int col) { if (row > col) { return 0; } else { return randomGenerator.Next(); } } } // end class MatrixGenerator Von: jkalias ***@***.***> Gesendet: Samstag, 28. September 2024 15:00 An: mathnet/mathnet-numerics ***@***.***> Cc: Anatom70 ***@***.***>; Author ***@***.***> Betreff: Re: [mathnet/mathnet-numerics] matrix<double> operator == performs false on identical matrices (Issue #1089) What do you mean it's not reproducible? Can you provide a code snippet for this 12x12 matrix? Or at bare minimum print out the matrix for which this happens, otherwise the bug can't be fixed. — Reply to this email directly, view it on GitHub <#1089 (comment)> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/BKT7QJ32L54J6LXZ4JZ2GELZY2R4TAVCNFSM6AAAAABMXODXA2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDGOBQGYZTEMZUG4> . You are receiving this because you authored the thread. <https://github.com/notifications/beacon/BKT7QJ2ABJIK7A2VBNPYST3ZY2R4TA5CNFSM6AAAAABMXODXA2WGG33NNVSW45C7OR4XAZNMJFZXG5LFINXW23LFNZ2KUY3PNVWWK3TUL5UWJTUN4WIRW.gif> Message ID: ***@***.*** ***@***.***> >

[jkalias]

Wow, this is a bit...difficult to read :)
Could you please repost it, but not from an email client? Perhaps directly in github.com?
Thank you for effort though

[wo80]

The == operator is defined for every .NET reference type, see https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/equality-operators#reference-types-equality

Since Math.NET doesn't overload this operator, the == test will fail (you are comparing two different objects), but the call to Equals succeeds since the method is overloaded indeed, see https://github.com/mathnet/mathnet-numerics/blob/master/src/Numerics/LinearAlgebra/Matrix.BCL.cs#L51

So the question is, whether the == operator should be implemented in Math.NET.