><span class='op'>(</span>
  <span class='va'>xf</span>,
  <span class='va'>xnf</span>,
  <span class='va'>yf</span>,
  probs <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/seq.html'>seq</a></span><span class='op'>(</span><span class='fl'>0</span>, <span class='fl'>1</span>, <span class='fl'>0.25</span><span class='op'>)</span>,
  alpha <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/rep.html'>rep</a></span><span class='op'>(</span><span class='fl'>1</s