Classes related to model integration

Classes
class	ImportanceSampler
	Calculates DecayTreeVectorIntegral using importance sampling. More...
class	IntegralElement< T >
	Holds the values of a component of an integral. More...
class	Integrator
	Integrates a model. More...
class	ModelIntegral
	Stores integral of a full model. More...

Detailed Description

Each DecayTree holds a product of free amplitudes ("a", below) and a product of data-dependent amplitudes ("A", below)

This class holds two types of components:
o Diagonal components: one for each DecayTree, stored as |A|^2 for the tree and returned as |a|^2 * stored value o Off-diagonal components: one for each pair of DecayTrees (i, j), stored as conj(A_i) * A_j and returned as 2 * real(conj(a_i) * a_i * stored value)