Small enhancement of computational electrophysiology manual section.

Added a note about what can be done if large membrane undulations turn out
to be a problem in a Computational Electrophysiology setup.

Change-Id: I5f50b4026ea1a8b88368b10c39d2207070c4740c

diff --git a/manual/special.tex b/manual/special.tex
index d77fef7a952232814e90ed4866b54c18681ff7d1..621b9a2d4de7b8b662a3fed959ccd7edb129710a 100644 (file)
--- a/manual/special.tex
+++ b/manual/special.tex
@@ -1137,6 +1137,11 @@ is the box length in that direction. If you have already defined index groups fo
 the channel for the single-layered system, {\tt gmx make_ndx -n index.ndx -twin} will
 provide you with the groups for the double-layered system.
 
+To suppress large fluctuations of the membranes along the swap direction,
+it may be useful to apply a harmonic potential (acting only in the swap dimension)
+between each of the two channel and/or bilayer centers using umbrella pulling
+(see section~\ref{sec:pull}).
+
 \subsection*{Multimeric channels}
 If a split group consists of more than one molecule, the correct PBC image of all molecules
 with respect to each other has to be chosen such that the channel center can be correctly