private static void CheckFactorization(SkylineMatrix originalMatrix, int expectedNullity, double tolerance)
        {
            var factorization = originalMatrix.FactorSemidefiniteCholesky(false, tolerance);

            Assert.True(factorization.DependentColumns.Count == expectedNullity,
                        $"Nullity = {factorization.DependentColumns.Count} != {expectedNullity} (expected)");
            SemidefiniteCholeskyFullTests.CheckNullSpace(originalMatrix, factorization.NullSpaceBasis, tolerance);
        }