--- DarthVader/TrackerLevel2/src/F77/functionspfa.f	2006/10/26 16:22:37	1.5
+++ DarthVader/TrackerLevel2/src/F77/functionspfa.f	2006/12/01 10:43:18	1.6
@@ -153,6 +153,7 @@
 c      logical DEBUG
 c      common/dbg/DEBUG
 
+c      print*,'## pfaeta2 ',ic,angle
       iview = VIEW(ic)              !(1)
       lad = nld(MAXS(ic),VIEW(ic)) !(1)
       cog2 = cog(2,ic)             !(1)
@@ -277,6 +278,7 @@
 c      logical DEBUG
 c      common/dbg/DEBUG
 
+c      print*,'## pfaeta3 ',ic,angle
 
       iview = VIEW(ic)              !(1)
       lad = nld(MAXS(ic),VIEW(ic)) !(1)
@@ -400,6 +402,8 @@
 c      logical DEBUG
 c      common/dbg/DEBUG
 
+c      print*,'## pfaeta4 ',ic,angle
+
       iview = VIEW(ic)             !(1)
       lad = nld(MAXS(ic),VIEW(ic)) !(1)
       cog4=cog(4,ic)               !(1)
@@ -656,25 +660,29 @@
          
          COG = 0.
          
+c         print*,'## ',sl2,sl1,sc,sr1,sr2
+
          if(ncog.eq.1)then
             COG = 0.
          elseif(ncog.eq.2)then
             if(sl1.gt.sr1)then
-               COG = -sl1/(sl1+sc)        
+               if((sl1+sc).ne.0)COG = -sl1/(sl1+sc)        
             elseif(sl1.le.sr1)then
-               COG = sr1/(sc+sr1)            
+               if((sc+sr1).ne.0)COG = sr1/(sc+sr1)            
             endif
          elseif(ncog.eq.3)then
-            COG = (sr1-sl1)/(sl1+sc+sr1) 
+             if((sl1+sc+sr1).ne.0)COG = (sr1-sl1)/(sl1+sc+sr1) 
          elseif(ncog.eq.4)then
             if(sl2.gt.sr2)then
-               COG = (sr1-sl1-2*sl2)/(sl2+sl1+sc+sr1) 
+               if((sl2+sl1+sc+sr1).ne.0) 
+     $              COG = (sr1-sl1-2*sl2)/(sl2+sl1+sc+sr1) 
             elseif(sl2.le.sr2)then
-               COG = (2*sr2+sr1-sl1)/(sl2+sl1+sc+sr1) 
+                if((sl2+sl1+sc+sr1).ne.0)
+     $              COG = (2*sr2+sr1-sl1)/(sl2+sl1+sc+sr1) 
             endif
          else
             print*,'function COG(NCOG,IC) ==> WARNING!! NCOG=',NCOG
-            print*,'                 (NCOG must be <= 4)'
+            print*,'                 (NCOG must be 0-4)'
             COG = 0.
          endif
 
@@ -730,7 +738,7 @@
 
       endif
 
-c      print *,ncog,ic,cog,'/////////////'
+c      print *,'## cog ',ncog,ic,cog,'/////////////'
 
       return
       end