AliPhysics  0bb4a45 (0bb4a45)
LinearSigmaCombiner Struct Reference
Inheritance diagram for LinearSigmaCombiner:

## Public Member Functions

double W (const Result &r) const

double StepW (double guess, const Result &r) const

double StepOffset (double, const Result &) const

double TermVar (double guess, const Result &r) const

Public Member Functions inherited from Combiner
virtual ~Combiner ()

double Term (double guess, const Result &r) const

double F (double guess, double chi2, const_iterator &begin, const_iterator &end) const

double FindError (unsigned short nIter, const_iterator &begin, const_iterator &end, int sign, double best, double chi2, double s)

double FindX (unsigned short nIter, const_iterator &begin, const_iterator &end, double lowest, double highest)

Final Calculate (const_iterator &begin, const_iterator &end, unsigned short nIter=50)

## Static Public Member Functions

static double L (double guess, double x, double el, double eh)

static double WrapL (double *xp, double *pp)

## Additional Inherited Members

Public Types inherited from Combiner
typedef List::iterator iterator

typedef List::const_iterator const_iterator

## Detailed Description

A combiner that uses a linear $$\sigma$$ approximation

Definition at line 465 of file Combiner.C.

## Member Function Documentation

 static double LinearSigmaCombiner::L ( double guess, double x, double el, double eh )
inlinestatic

Return the likely-hood function value at $$x'$$:

$L(x') = \left[(x'-x) / (s + s'(x'-x))\right]^2$

where

$s = 2\sigma^+\sigma^-/(\sigma^++\sigma^-)$

$s' = (\sigma^+-\sigma^-)/(\sigma^++\sigma^-)$

Parameters
 guess $$x'$$ x $$x$$ el $$\sigma^-$$ eh $$\sigma^+$$
Returns

Definition at line 548 of file Combiner.C.

 double LinearSigmaCombiner::StepOffset ( double , const Result & ) const
inlinevirtual

Calculate the bias.

Returns
0

Implements Combiner.

Definition at line 505 of file Combiner.C.

 double LinearSigmaCombiner::StepW ( double guess, const Result & r ) const
inlinevirtual

Calculate the weight based on a guess of best $$x'$$

$w(x') = s / [s + s' (x' - x)]^3$

Parameters
 guess Current guess $$x'$$ r Observation
Returns
$$W(x')$$

Implements Combiner.

Definition at line 495 of file Combiner.C.

 double LinearSigmaCombiner::TermVar ( double guess, const Result & r ) const
inlinevirtual

Calculate the contribution variance to the $$\chi^2$$ with the guess $$x'$$.

$v(x') = [s + s' (x' - x)]^2$

Parameters
 guess Current guess $$x'$$ r Observation
Returns
$$v(x')$$

Implements Combiner.

Definition at line 522 of file Combiner.C.

 double LinearSigmaCombiner::W ( const Result & r ) const
inlinevirtual

Calculate the weight

$w = 1/2 (s + x s')^3 / s$

Parameters
 r Observation
Returns
$$W$$

Implements Combiner.

Definition at line 478 of file Combiner.C.

 static double LinearSigmaCombiner::WrapL ( double * xp, double * pp )
inlinestatic

Wrap likely-hood function for ROOT

Parameters
 xp Pointer to independent variables pp Pointer to parameters
Returns
Likely-hood function evaluate at xp

Definition at line 563 of file Combiner.C.

Referenced by DrawResult::MakeF().

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