spin_order
This Spin3 keyword selects the highest contraction level supplied to the neural network:
spin_order <order>
The value can be 1, 2, or 3 and defaults to 3. It is used only with
spin_version 1.
Value |
Descriptor content |
|---|---|
1 |
local spin invariants and direct one-edge contractions |
2 |
order 1 plus edge powers, density norms, and two-leg correlations |
3 |
order 2 plus nested three-leg contractions |
The levels are nested: order 1 is a prefix of order 2, which is a prefix of
order 3. spin_order is not the body order of the final energy. The
neural network is nonlinear and can combine these coordinates with each other
and with the structural NEP descriptor. See O/C contraction hierarchy for
the explicit construction.