Solver is not initialized when trying to run `DP_Inverter_Grid_Sequential_FreqSplit`

[cuihantao]

Describe the bug

The executable DP_Inverter_Grid_Sequential_FreqSplit errors out the following:

Simulate sequence 2
[11:53:51.924895 MnaSolverFactory info] creating SparseLUAdapter solver implementation
DP_Inverter_Grid_Sequential_FreqSplit: /usr/include/eigen3/Eigen/src/SparseCore/SparseSolverBase.h:90: const Eigen::Solve<Derived, Rhs> Eigen::SparseSolverBase<Derived>::solve(const Eigen::MatrixBase<OtherDerived>&) const [with Rhs = Eigen::Matrix<double, -1, -1>; Derived = Eigen::SparseLU<Eigen::SparseMatrix<double, 1>, Eigen::COLAMDOrdering<int> >]: Assertion `m_isInitialized && "Solver is not initialized."' failed.
Aborted (core dumped)

To Reproduce
Steps to reproduce the behavior:

1. Build the project
2. Go to build_folder/dpsim/examples/cxx
3. Run ./DP_Inverter_Grid_Sequential_FreqSplit --option seq=2

I am not sure what seq means, but changing it from 2 to 0 won't help.

Expected behavior

Normal completion.

Desktop (please complete the following information):

• OS: Ubuntu 22.04 LTS
• Eigen: 3.4.0, apt-get installation