<span class="comment">% wire segment capacitance is an affine function of widths</span>
    C_bar = beta.*l.*w + gamma.*l;
    C_bar = [0; C_bar];

    <span class="comment">% compute common capacitances for each node (C_tilde in GP tutorial)</span>
    C_tilde = cvx( zeros(N,1) );
    <span class="keyword">for</span> node = [1:N]
      C_tilde(node,1) = Cload(node);
      <span class="keyword">for</span> k = parent(node)
        <span class="keyword">if</span> k &gt; 0; C_tilde(node,1) = C_tilde(node,1) + 