se/sweep.html" class="external-link">sweep</a></span><span class="op">(</span><span class="va">X</span><span class="op">[</span><span class="op">-</span><span class="va">ind</span>, <span class="op">]</span>, <span class="fl">2</span>, <span class="va">test</span><span class="op">$</span><span class="va">center</span>, <span class="st">'-'</span><span class="op">)</span>, <span class="fl">2</span>, <span class="va">test</span><span class="op">$</span><span class="va">scale</span>, <span class="st">'/'</span