EvtLinSample Struct Reference

Description: The simple helper class to generate arbitrary distribution based on a linear piece-wise approximation of it. More...

Public Member Functions
	EvtLinSample ()
	The default constructor.
	EvtLinSample (const std::vector< EvtPointf > &_v)
	The primary constructor with an actual shape to generate.
void	init (const std::vector< EvtPointf > &_v)
	The method to initialize data.
std::pair< double, double >	operator() (double) const
	The operator to return <x,weight> depend on argument in [0,1] range which represent fraction of the total distribution integral.

Public Attributes
std::vector< EvtPointf >	m_v
	shape data
std::vector< double >	m_I
	cumulative integral data

Detailed Description

Description: The simple helper class to generate arbitrary distribution based on a linear piece-wise approximation of it.

Definition at line 68 of file EvtbTosllNPR.cc.

Constructor & Destructor Documentation

EvtLinSample() [1/2]

EvtLinSample ( )

inline

The default constructor.

Definition at line 72 of file EvtbTosllNPR.cc.

{}

EvtLinSample() [2/2]

EvtLinSample ( const std::vector< EvtPointf > & _v )

inlineexplicit

The primary constructor with an actual shape to generate.

Definition at line 77 of file EvtbTosllNPR.cc.

{ init(_v); }

Member Function Documentation

init()

void init

(

const std::vector< EvtPointf > &

_v

)

The method to initialize data.

The method to initialize a cumulative integral of the piece-wise approximation provided as input _v.

Definition at line 187 of file EvtbTosllNPR.cc.

{
  m_v = _v;
  m_I.push_back(0);
  for (unsigned i = 0; i < m_v.size() - 1; i++)
    m_I.push_back((m_v[i + 1].y + m_v[i + 0].y) * (m_v[i + 1].x - m_v[i + 0].x) + m_I.back());
  double norm = 1 / m_I.back();
  for (unsigned i = 0; i < m_v.size(); i++)
    m_I[i] *= norm;
}

operator()()

std::pair< double, double > operator()

(

double

r

)

const

The operator to return <x,weight> depend on argument in [0,1] range which represent fraction of the total distribution integral.

Sample from the cumulative integral and return q^2 and the associated weight.

Definition at line 202 of file EvtbTosllNPR.cc.

{
  int j = upper_bound(m_I.begin(), m_I.end(), r) - m_I.begin();
  double dI = m_I[j] - m_I[j - 1];
  r = (r - m_I[j - 1]) / dI;
  double f0 = m_v[j - 1].y, f1 = m_v[j].y, x0 = m_v[j - 1].x, x1 = m_v[j].x,
         df = f1 - f0, dx = x1 - x0, z;
  if (fabs(df) > f0 * 1e-3) {
    z = (f1 * x0 - x1 * f0 + dx * sqrt(df * (f0 + f1) * r + f0 * f0)) / df;
  } else {
    if (f0 > f1) {
      z = x0 + (r * dx) * (f1 - r * df) / f0;
    } else {
      z = x1 - (r * dx) * (f0 + r * df) / f1;
    }
  }
  return std::make_pair(z, f0 + (df / dx) * (z - x0));
}

Member Data Documentation

m_I

std::vector<double> m_I

cumulative integral data

Definition at line 94 of file EvtbTosllNPR.cc.

m_v

std::vector<EvtPointf> m_v

shape data

Definition at line 91 of file EvtbTosllNPR.cc.

---

The documentation for this struct was generated from the following file:

• generators/evtgen/models/src/EvtbTosllNPR.cc