pan>
<span class="sd">        K(A, B) &amp;= \mathrm{Tr} \mathbf{P}^\\alpha \mathbf{C}(A, B)</span>

<span class="sd">        \mathbf{P}^\\alpha &amp;= \\argmax_{\mathbf{P} \in \mathcal{U}(N, N)} \sum_{ij} P_{ij} (1-C_{ij} +\\alpha \ln P_{ij})</span>

<span class="sd">    where the similarity between local atomic environments :math:`C_{ij}` has</span>
<span class="sd">    been calculated with the pairwise metric (e.g. linear, gaussian) defined by</span>
<span class="sd">    the parameters given in the const