n <span class="math inline">\(S^{n-1}\)</span>.</p>
<div id="warning-undefined-at-zero" class="section level4 unnumbered">
<h4>Warning: undefined at zero!</h4>
<p>The above mapping from <span class="math inline">\(\mathbb{R}^n\)</span> to <span class="math inline">\(S^n\)</span> is not defined at zero.
While this point outcome has measure zero during sampling, and may
thus be ignored, it is the default initialization point and thus unit
vector parameters cannot be initialized at zero. A simple workaround
is