Distance between the unit cells of two interacting
spins, stored in a \([3\times n_{coupling}]\) matrix.

atom1

First magnetic atom, pointing to the list of
magnetic atoms in the list generated by spinw.matom, stored in a
row vector with \(n_{coupling}\) element.

atom2

Second magnetic atom, same as atom1.

mat_idx

Stores pointers to matrices for every coupling in a
\([3\times n_{coupling}]\) matrix, maximum three matrix per
coupling (zeros for no coupling) is allowed.

idx

Neighbor index, increasing indices for the equivalent
couplings, starting with 1,2,… which means first and second
neighbor bonds, respectively.

type

Type of coupling corresponding to mat_idx matrices.
Default is 0 for quadratic exchange, type = 1 for
biquadratic exchange.

sym

If true the bond symmetry operators will be applied
on the assigned matrix.

rdip

Maximum distance until the dipolar interaction is
calculated. Zero value means no dipolar interactions
are considered.

nsym

The largest bond idx value that is generated
using the space group operators. Typically very long bonds for
dipolar interactions won’t be calculated using space group
symmetry.