class RooProdPdf: public RooAbsPdf

 Default constructor

 Dummy constructor

 Constructor with 2 PDFs (most frequent use case).

 The optional cutOff parameter can be used as a speed optimization if
 one or more of the PDF have sizable regions with very small values,
 which would pull the entire product of PDFs to zero in those regions.

 After each PDF multiplication, the running product is compared with
 the cutOff parameter. If the running product is smaller than the
 cutOff value, the product series is terminated and remaining PDFs
 are not evaluated.

 There is no magic value of the cutOff, the user should experiment
 to find the appropriate balance between speed and precision.
 If a cutoff is specified, the PDFs most likely to be small should
 be put first in the product. The default cutOff value is zero.

 Constructor from a list of PDFs

 The optional cutOff parameter can be used as a speed optimization if
 one or more of the PDF have sizable regions with very small values,
 which would pull the entire product of PDFs to zero in those regions.

 After each PDF multiplication, the running product is compared with
 the cutOff parameter. If the running product is smaller than the
 cutOff value, the product series is terminated and remaining PDFs
 are not evaluated.

 There is no magic value of the cutOff, the user should experiment
 to find the appropriate balance between speed and precision.
 If a cutoff is specified, the PDFs most likely to be small should
 be put first in the product. The default cutOff value is zero.

 Constructor from named argument list

 fullPdf -- Set of 'regular' PDFS that are normalized over all their observables
 Conditional(pdfSet,depSet) -- Add PDF to product with condition that it
                               only be normalized over specified observables
                               any remaining observables will be conditional
                               observables


 For example, given a PDF F(x,y) and G(y)

 RooProdPdf("P","P",G,Conditional(F,x)) will construct a 2-dimensional PDF as follows:

   P(x,y) = G(y)/Int[y]G(y) * F(x,y)/Int[x]G(x,y)

 which is a well normalized and properly defined PDF, but different from the

  P'(x,y) = F(x,y)*G(y) / Int[x,y] F(x,y)*G(y)

 In the former case the y distribution of P is identical to that of G, while
 F only is used to determine the correlation between X and Y. In the latter
 case the Y distribution is defined by the product of F and G.

 This P(x,y) construction is analoguous to generating events from F(x,y) with
 a prototype dataset sampled from G(y)

 Constructor from named argument list

 fullPdf -- Set of 'regular' PDFS that are normalized over all their observables
 Conditional(pdfSet,depSet) -- Add PDF to product with condition that it
                               only be normalized over specified observables
                               any remaining observables will be conditional
                               observables


 For example, given a PDF F(x,y) and G(y)

 RooProdPdf("P","P",G,Conditional(F,x)) will construct a 2-dimensional PDF as follows:

   P(x,y) = G(y)/Int[y]G(y) * F(x,y)/Int[x]G(x,y)

 which is a well normalized and properly defined PDF, but different from the

  P'(x,y) = F(x,y)*G(y) / Int[x,y] F(x,y)*G(y)

 In the former case the y distribution of P is identical to that of G, while
 F only is used to determine the correlation between X and Y. In the latter
 case the Y distribution is defined by the product of F and G.

 This P(x,y) construction is analoguous to generating events from F(x,y) with
 a prototype dataset sampled from G(y)

 Internal constructor from list of named arguments

 Copy constructor

 Initialize RooProdPdf configuration from given list of RooCmdArg configuration arguments
 and set of 'regular' p.d.f.s in product

 Destructor

 Overload getVal() to intercept normalization set for use in evaluate()

 Calculate current value of object

 Calculate running product of pdfs terms, using the supplied
 normalization set in 'normSetList' for each component

 Factorize product in irreducible terms for given choice of integration/normalization

 Return list of (partial) integrals of product terms for integration
 of p.d.f over observables iset while normalization over observables nset.
 Also return list of normalization sets to be used to evaluate
 each component in the list correctly.

 Group product into terms that can be calculated independently

 Calculate integrals of factorized product terms over observables iset while normalized
 to observables in nset.

 Make an appropriate automatic name for a RooGenProdProj object in getPartIntList()

 Force RooRealIntegral to offer all observables for internal integration

 Determine which part (if any) of given integral can be performed analytically.
 If any analytical integration is possible, return integration scenario code.

 RooProdPdf implements two strategies in implementing analytical integrals

 First, PDF components whose entire set of dependents are requested to be integrated
 can be dropped from the product, as they will integrate out to 1 by construction

 Second, RooProdPdf queries each remaining component PDF for its analytical integration
 capability of the requested set ('allVars'). It finds the largest common set of variables
 that can be integrated by all remaining components. If such a set exists, it reconfirms that
 each component is capable of analytically integrating the common set, and combines the components
 individual integration codes into a single integration code valid for RooProdPdf.

 Return analytical integral defined by given scenario code

 Obsolete

 If this product contains exactly one extendable p.d.f return the extension abilities of
 that p.d.f, otherwise return CanNotBeExtended

 Return the expected number of events associated with the extentable input p.d.f
 in the product. If there is no extendable term, return zero and issue and error

 Return generator context optimized for generating events from product p.d.f.s

 Query internal generation capabilities of component p.d.f.s and aggregate capabilities
 into master configuration passed to the generator context

 Forward one-time initialization call to component generation initialization
 methods.

 Generate a single event with configuration specified by 'code'
 Defer internal generation to components as encoded in the _genCode
 registry for given generator code.

 Forward determination of safety of internal generator code to
 component p.d.f that would generate the given observable

 Look up user specified normalization set for given input PDF component

 Return all parameter constraint p.d.f.s on parameters listed in constrainedParams
 The observables set is required to distinguish unambiguously p.d.f in terms
 of observables and parameters, which are not constraints, and p.d.fs in terms
 of parameters only, which can serve as constraints p.d.f.s

 Forward the plot sampling hint from the p.d.f. that defines the observable obs

 Customized printing of arguments of a RooProdPdf to more intuitively reflect the contents of the
 product operator construction