<acronym>deal.II</acronym>?</a>
<li> <a href="#problem-howto">How do I solve problem XXX with
<acronym>deal.II</acronym>?</a>
+ <li> <a href="#problem-complex">Can I solve problems over complex numbers?</a>
<li> <a href="#time-dependent">There is no tutorial program for
time-dependent problems!</a>
<li> <a href="#contribute">I want to contribute to the development
</p>
+ <a name="problem-complex"></a>
+ <h3>Can I solve problems over complex numbers?</h3>
+
+ <p>
+ Yes, you can, and it has been done numerous times with
+ <acronym>deal.II</acronym>. However, we have a standard
+ recommendation: consider such problems as systems of partial
+ differential equations, where the individual components of the
+ solution are the real and imaginary part of your unknown. The reason
+ for this is that for complex-valued problems, the product
+ <tt><u,v></tt> of two vectors is not the same as
+ <tt><v,u></tt>, and it is very easy to get this wrong in many
+ places. If you want to avoid these common traps, then the easiest
+ way around is to split up you equation into two equations of real
+ and imaginary part first, and then treat the resulting system as a
+ system of real variables. This also makes the type of linear system
+ clearer that you get after discretization, and tells you something
+ about which solver may be adequate for it.
+ </p>
+
+
<a name="time-dependent"></a>
<h3>There is no tutorial program for
time-dependent problems!</h3>