# Resolve "Include MSCBDECOMP + higher order checkerboard"

Closes #175 . This now has the basic functionality that I wanted to implement:

- Automatic Decomposition
- A selection of approximations to the exact exponential.

To that end a new section in the parameter file has been added.(See Scripts_and_parameters) possible values for method:

- 0: Disable it
- 1: S_1 1 Euler Approximation
- 2: S_1 2 Strang splitting
- 3: SE_2 2 splitting by Blanes et al. (2014)
- 4: S_3 4 splitting by Neri(1987), Forest(1990), Yoshida(1990)
- 5: S_6 4 splitting by Blanes et al. (2002)

The Euler Approximation tends to be unstable(Hubbard, N=4 -> N=6 -> N=8), the others always worked.

unimplemented things:

- projector matrix P assumes P(i) == i -> ignored

General assumptions:

- Op_T constitutes a hermitian matrix. By this Op_T%g has to be real.

Edited by Florian Goth