// will probably not work since the matrix will not always be positive definite
//[SkippableFact]
private static void TestRowAdditionReverse()
{
Skip.IfNot(TestSettings.TestSuiteSparse, TestSettings.MessageWhenSkippingSuiteSparse);
Matrix original = Matrix.CreateFromArray(SparsePosDef10by10.Matrix);
Vector rhs = Vector.CreateFromArray(SparsePosDef10by10.Rhs);
// Start the matrix as diagonal
var matrixExpected = Matrix.CreateIdentity(original.NumColumns);
var dok = DokSymmetric.CreateIdentity(SparsePosDef10by10.Order);
var factor = CholeskySuiteSparse.Factorize(dok.BuildSymmetricCscMatrix(true), false);
for (int i = 0; i < matrixExpected.NumRows; ++i)
{
// Update matrix
Vector newRowVector = original.GetRow(i);
matrixExpected.SetSubrow(i, newRowVector);
matrixExpected.SetSubcolumn(i, newRowVector);
//Console.WriteLine($"\nOnly dofs [0, {i}]");
factor.AddRow(i, SparseVector.CreateFromDense(newRowVector));
// Solve new linear system
Vector solutionExpected = matrixExpected.FactorCholesky(true).SolveLinearSystem(rhs);
Vector solutionComputed = factor.SolveLinearSystem(rhs);
comparer.AssertEqual(solutionExpected, solutionComputed);
}
}
