Question on heisenberg_pairs

[sfragkos]

Hello everyone!

I have a question regarding the heisenberg_pairs tag.

If, for example, I give the value of J12, should I also define the J21?

In addition, in the Hamiltonian tab of the GUI, the Pairs section is disabled (see figure below). Do you know why?
**

**

[GPMueller]

If, for example, I give the value of J12, should I also define the J21?

The Heisenberg pairs are automatically symmetry-reduced, so there's no difference whether you only specify J_12 or also J_21.

in the Hamiltonian tab of the GUI, the Pairs section is disabled

This is intentional. I'm afraid we haven't implemented the appropriate APIs in the core library for the GUI to be able to specify pairs the way it's done in the input file.
I believe @MSallermann worked out a first prototype of a scriptable API (using chaiscript), which would in principle be able to handle this?