+ /**
+ * Make a dead map based on the noise of the channels. If the noise
+ * of a paraticular channel is larger than @a maxW, then the channel
+ * is marked as dead.
+ *
+ * If the argument @a dead is non-null, then the map passed is
+ * modified. That is, channels marked as dead in the map will
+ * remain marked. Channels that meat the criterion (noise larger
+ * than @a maxW) will in addition be marked as dead.
+ *
+ * If the argument @a dead is null, then a new map is created and a
+ * pointer to this will be returned.
+ *
+ * @param maxW Maximum value of noise for a channel before it is
+ * marked as dead.
+ * @param dead If non-null, then modify this map.
+ *
+ * @return A pointer to possibly newly allocated dead map.
+ */
+ AliFMDBoolMap* MakeDeadMap(Float_t maxW, AliFMDBoolMap* dead=0) const;