Questions

What are the best choices for input and output?

The possible combinations are

1. ZA > Nbody
2. 2LPT > Nbody
3. ZA > Nbody-ZA
4. 2LPT > Nbody-2LPT
5. ZA > Nbody-2LPT

Any else?

The advantage of having ZA as input is that it has more information than 2LPT.

The advantage of having 2LPT as input is that we start with more accurate quasi-linear scale displacement and long-short mode coupling. This is also the case when using Nbody-2LPT as the output.

Is the bias in the power ratio a fluke before convergence?

Yes it seems so.

How big is the cosmology dependence?

In other words is the final field well approximated by a function of the initial field only? What about the growth history?

What's a good test case? LCDM vs matter-dominated?

If dependence is big, how to incorporate them?