) corner points of the z-shape.</p></li>
</ul>
</dd>
<dt>bell:  </dt><dd><ul class="simple">
<li><p>r(1) = divisor of the distance value</p></li>
<li><p>r(2) = exponent of generalized bell-shaped function</p></li>
</ul>
</dd>
<dt>gaussian:  </dt><dd><ul class="simple">
<li><p>r = a scalar whose value scales the slope of the Gaussian curve.</p></li>
</ul>
</dd>
<dt>constgaussian:  </dt><dd><ul class="simple">
<li><p>r = a scalar whose value defines the lower 
threshod and shape of the Gaussian curve.</p></li