
<p>A 2-dimensional integration, implemented by nested calls to <code>romberg</code>.
</p>
<pre class="example">(%i1) load (romberg);
(%o1)    /usr/share/maxima/5.11.0/share/numeric/romberg.lisp
(%i2) g(x, y) := x*y / (x + y);
                                    x y
(%o2)                   g(x, y) := -----
                                   x + y
(%i3) rombergtol : 1e-6;
(%o3)                 9.9999999999999995E-7
(%i4) estimate : romberg (romberg (g(x, y), y, 0, x/2), x, 1, 3);
(%o4)                   0.81