1. update ostap.utils.valerrors & and new test

ReleaseNotes/release_notes.md

@@ -11,15 +11,17 @@
   1. Activate a new `draw` method (via `tree_draw`) for `ROOT.TTree`
   1. add `progress` and `report` optioal argumens for (almost) all Frame-related functions 
   1. Some tweaks for style configuration 
-
-## Backward incompatible
+  1. update `ostap.utils.valerrors` & and new test
+
+## Backward incompatibl
 
   1. `project`(&`draw`) for 2 and 3-dimession now follows the natural order of varibales:
        `XX.project ( target , 'x,y,z' , ...) `
   1. For `eff` & effic' and `efficinecy` methods fo r1D histograms
      the confusing  optional argument `increasing=True` is replced by (less-confusin)
      `cut_low` and the argument is not optionl anymore
-
+  1. From now for weighted datasets `dataset[i]` returns `(entry,weight)` tuple    
+  1. from now iteration over weighted dataset gives `(entry,weight)` tuple
 
 ## Bug fixes
 

ostap/fitting/dataset.py

@@ -41,6 +41,7 @@
 from   ostap.utils.utils         import evt_range, LAST_ENTRY, ALL_ENTRIES 
 from   ostap.stats.statvars      import data_decorate, data_range 
 from   ostap.histos.histos       import histo_book
+from   ostap.utils.valerrors     import VAE 
 import ostap.fitting.roocollections
 import ostap.fitting.printable
 import ROOT, random, math, sys, ctypes  
@@ -59,9 +60,7 @@
 _maxv =  0.99 * sys.float_info.max
 _minv = -0.99 * sys.float_info.max
 # =============================================================================
-
-# =============================================================================
-## iterator for RooAbsData
+## iterator for RooAbsData entries 
 #  - For unweighted dataset `entry` is a RooArsSet
 #  @cdoe
 #  dataset = ...
@@ -125,11 +124,11 @@ def _rad_getitem_ ( data , index ) :
 
         entry = data.get ( index )
         if not data.isWeighted() : return entry 
-
+        
         weight = data.weight()        
         if   data.store_asym_error () :
-            wel, weh = data.weightErrors ()
-            return entry, weight , wel, weh      ## RETURN 
+            wel , weh = data.weightErrors ()
+            weight    = VAE ( weight , wel , weh ) 
         elif data.store_error      () :
             we = data.weightError  ()
             if 0 <= we : weight = VE ( weight , we * we ) 

ostap/histos/graphs.py

@@ -1021,8 +1021,7 @@ def _grae_setitem_ ( graph , ipoint , point ) :
     assert 2 <= n <= 6 , "Invalid lenght of 'point' object"
 
     pars = point
-
-
+
     ## extract X
     p0 = pars [ 0 ]
     ## "ready-to-use" 
@@ -1093,8 +1092,7 @@ def _grae_iteritems_ ( graph ) :
 
 # =============================================================================
 
-
-if (6,20) <= root_info : 
+if ( 6 , 20 ) <= root_info : 
     # =============================================================================
     ## iterate over points in TGraphMultiErrors
     #  @code