i</span>, <span class="va">pi</span><span class="op">)</span></span>
<span><span class="fu">transf.rtod</span><span class="op">(</span><span class="va">xi</span>, <span class="va">n1i</span>, <span class="va">n2i</span><span class="op">)</span></span>
<span><span class="fu">transf.rpbtod</span><span class="op">(</span><span class="va">xi</span>, <span class="va">n1i</span>, <span class="va">n2i</span><span class="op">)</span></span>
<span><span class="fu">transf.lnortord</span><span class="op">(</span><span