base/c.html" class="external-link">c</a></span><span class="op">(</span>initial<span class="op">=</span><span class="fl">1</span>, lower<span class="op">=</span><span class="fl">1e-10</span>, upper<span class="op">=</span><span class="fl">30</span><span class="op">)</span>,</span>
<span>  sigma_y <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span>initial<span class="op">=</span><span class="fl">1e-1</span>, lower<span