Index: trunk/psModules/src/detrend/pmDark.h
===================================================================
--- trunk/psModules/src/detrend/pmDark.h	(revision 24801)
+++ trunk/psModules/src/detrend/pmDark.h	(revision 24802)
@@ -13,5 +13,6 @@
 // An ordinate for fitting darks
 typedef struct {
-    psString name;                      // Name of concept to fit
+    psString name;                      // Name of ordinate
+    psString rule;                      // Rule for generating ordinate (math on concepts)
     int order;                          // Polynomial order to fit
     bool scale;                         // Rescale values?