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Reference Guide
VariableMetricEDMEstimator.cxx
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1 // @(#)root/minuit2:$Id$
2 // Authors: M. Winkler, F. James, L. Moneta, A. Zsenei 2003-2005
3 
4 /**********************************************************************
5  * *
6  * Copyright (c) 2005 LCG ROOT Math team, CERN/PH-SFT *
7  * *
8  **********************************************************************/
9 
12 #include "Minuit2/MinimumError.h"
13 
14 namespace ROOT {
15 
16 namespace Minuit2 {
17 
18 double similarity(const LAVector &, const LASymMatrix &);
19 
21 {
22  // estimate the edm (expected distance to the minimum) = 0.5 * g^T V g (where V is the error matrix, inverse of
23  // Hessian) assuminigfirst derivatives if F are zero at the mminimum,
24 
25  if (e.InvHessian().size() == 1)
26  return 0.5 * g.Grad()(0) * g.Grad()(0) * e.InvHessian()(0, 0);
27 
28  double rho = similarity(g.Grad(), e.InvHessian());
29  return 0.5 * rho;
30 }
31 
32 } // namespace Minuit2
33 
34 } // namespace ROOT
e
#define e(i)
Definition: RSha256.hxx:103
VariableMetricEDMEstimator.h
ROOT::Minuit2::FunctionGradient
Definition: FunctionGradient.h:21
FunctionGradient.h
ROOT::Minuit2::VariableMetricEDMEstimator::Estimate
double Estimate(const FunctionGradient &, const MinimumError &) const
Definition: VariableMetricEDMEstimator.cxx:20
ROOT::Minuit2::similarity
double similarity(const LAVector &, const LASymMatrix &)
Definition: LaVtMVSimilarity.cxx:20
ROOT::Minuit2::MinimumError
MinimumError keeps the inv.
Definition: MinimumError.h:28
MinimumError.h
ROOT
tbb::task_arena is an alias of tbb::interface7::task_arena, which doesn't allow to forward declare tb...
Definition: EExecutionPolicy.hxx:4
g
#define g(i)
Definition: RSha256.hxx:105