Dear Sureshravi,

unfortunately, we currently do not have an automatic way to extract the Jijs. Basically the problem you are facing is the mapping of the Energies of different configurations to the corresponding Jijs. Let me try to elaborate by considering a simple example:

If you have a single atom per unit cell and you would consider a magnetic Heisenberg model with only a single nearest neighbour J, then you could determine this J by looking at the energy difference between a FM and an AFM state. If you would like to get more Jijs (not only NN) you could also consider the Heisenberg model in reciprocal space and look for the J(q). These can than be easily determined by a Force-Theorem calculation of E(q) by the spin-spiral dispersion mode of FLEUR. If however, you have more than a single atom per unit-cell, this is more tricky and requires different spin-spiral calculations with different atoms being fixed and spiraling. The FLEUR jij-mode is supposed to be used in this case. However, it will only produce the energies of the configurations and not directly the Jij. You would have to do a Fourier transform to find them by mapping the energies to your magnetic model.

We are planing to also provide tools for these pre- and post-processing steps, but currently they are not available.

Hope this helps.
Daniel