al chirality. We neglect the Dzyaloshinskii-Moriya interaction, that can be introduced in a straightforward manner.</p><pre class="codeinput">J1 = 0.85;
J2 = 0.24;
J3 = 0.053;
J4 = 0.017;
J5 = 0.24;

banb.addmatrix(<span class="string">'value'</span>,J1,<span class="string">'label'</span>,<span class="string">'J1'</span>,<span class="string">'color'</span>,<span class="string">'red'</span>)
banb.addmatrix(<span class="string">'value'</span>,J2,<span class="string">'label'</span>,<span class="string">'J2'</s