lt is -1, 0, +1 symmetric triangular distribution.</span>
    <span class="comment">// Accessor functions.</span>
    <span class="identifier">RealType</span> <span class="identifier">lower</span><span class="special">()</span><span class="keyword">const</span><span class="special">;</span>
    <span class="identifier">RealType</span> <span class="identifier">mode</span><span class="special">()</span><span class="keyword">const</span><span class="special">;</span>
    <span class="identifier">RealType</span