">x</span><span class="op">)</span>,</span>
<span>  kernel_deriv_fn <span class="op">=</span> <span class="kw">function</span><span class="op">(</span><span class="va">x</span><span class="op">)</span> <span class="op">-</span><span class="fu"><a href="https://rdrr.io/r/base/Log.html" class="external-link">exp</a></span><span class="op">(</span><span class="op">-</span><span class="va">x</span><span class="op">)</span></span>
<span><span class="op">)</span></span></code></pre></div>
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