Decorations

Ostap decorates many ROOT.RooFit classes, adding more convinient methods to them.

RooArgList and RooArgSet

All these classes have got set of additional python-like methods for iteration, extension, addition, elemtn access checking the content etc... Also several methods to provide more coherent interfaces (e.g. add vs Add) are added.

RooAbsData and RooDataSet

These methods also have got the extended interface with many useful methods and operators, like e.g. concatenation of datasets a+b and merging them a*c.

RooDataSet class also has go many methods, that are similar to those of ROOT.TTree, in particular project and draw:

dataset = ... 
dataset.draw('mass','pt>1')  
histo   = ...
dataset.project ( histo , 'mass', 'pt>1' )

Many other methonds like statVar, sumVar , statCov , vminmax are also the same as for ROOT.TTree, see above.

s1    = dataset.statVar ('eff') 
s2    = dataset.sumVar  ('eff') 
r     = dataset.statCov ('eff','pt') 
mn,mx = dataset.vminmax ('eff')

RooFitResult

The class RooFitResult get many decorations that allow to access fit results

result = ...
par1 = result.params()  ## get all floating parameters 
par2 = result.params( float_only = False ) ## all parameters 
a,v  = result.param ( 'a' )      ## par by name 
a,v  = result.param (  a  )      ## par by RooFit object itself 
p    = result.a                 ## par as attribute 
for par in result :   print par                ## iteration 
for name,par in result.iteritems() : print par ## iteration
print result.cov  ( 'a' , 'b' )   ## get the covariance submatrix  
print result.corr ( 'a' , 'b'  )  ## get the correlation coefficient

Also the simple math with fiting parameters is supported

result = ...
s = result.sum       ('S','B' ) ## S+B
d = result.divide    ('S','B' ) ## S/B
s = result.subtract  ('B','B1') ## B-B1
m = result.multiply  ('A','B' ) ## A*B 
f = result.fraction  ('S','B' ) ## S/(S+B)

RooRealVar & friends

Few simple operations are added to simplify the calculations with RooRealVar objects:

x = ROOT.RooRealVar( ... )
x + 10 
x - 10 
x * 10 
x / 10 
10 + x 
10 - x 
10 * x 
10 / x
x += 2 
x -= 2 
x *= 2 
x /= 2 
x ** 3