n class="comment">% Derivative (local slope) estimation, for the Old Faithful Geyser Data.</span>
0004 <span class="comment">% The 'deriv' argument specifies derivative estimation,</span>
0005 <span class="comment">%   'deriv',1        First-order derivative.</span>
0006 <span class="comment">%   'deriv',[1 1]    Second-order derivative.</span>
0007 <span class="comment">%   'deriv',2        For bivariate fits, partial deriv. wrt second variable.</span>
0008 <span class="comment">%   'deriv',[1 2]    M