document Functions::LSingularityFunction

diff --git a/include/deal.II/base/function_lib.h b/include/deal.II/base/function_lib.h
index 6b61ac2ff06148f98977771b91997d971c9da434..48747e85bda080ec114123cd5d6f1a98900c1aaf 100644 (file)
--- a/include/deal.II/base/function_lib.h
+++ b/include/deal.II/base/function_lib.h
@@ -351,6 +351,10 @@ namespace Functions
   /**
    * Harmonic singularity on the L-shaped domain in 2D.
    *
+   * The function is given in polar coordinates by $r^{\frac{2}{3}}
+   * sin(\frac{2}{3} \phi)$ with a singularity in the origin and should be
+   * used with GridGenerator::hyper_L.
+   *
    * @ingroup functions
    * @author Guido Kanschat
    * @date 1999