ROOT   Reference Guide
SimplexSeedGenerator.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/MnFcn.h"
13#include "Minuit2/MinimumSeed.h"
14#include "Minuit2/MnStrategy.h"
17
18namespace ROOT {
19
20 namespace Minuit2 {
21
22
24 // create starting state for Simplex, which corresponds to the initial parameter values
25 // using the simple Initial gradient calculator (does not use any FCN function calls)
26 unsigned int n = st.VariableParameters();
27 const MnMachinePrecision& prec = st.Precision();
28
29 // initial starting values
31 for(unsigned int i = 0; i < n; i++) x(i) = st.IntParameters()[i];
32 double fcnmin = fcn(x);
33 MinimumParameters pa(x, fcnmin);
37 double dcovar = 1.;
38 for(unsigned int i = 0; i < n; i++)
40 MinimumError err(mat, dcovar);
41 double edm = VariableMetricEDMEstimator().Estimate(dgrad, err);
42 MinimumState state(pa, err, dgrad, edm, fcn.NumOfCalls());
43
44 return MinimumSeed(state, st.Trafo());
45}
46
48 // base class interface
49 return (*this)(fcn, (const GradientCalculator&)(gc), st, stra);
50}
51
52 } // namespace Minuit2
53
54} // namespace ROOT
const MnAlgebraicVector & G2() const
Class to calculate an initial estimate of the gradient.
Class describing a symmetric matrix of size n.
Definition: LASymMatrix.h:51
MinimumError keeps the inv.
Definition: MinimumError.h:26
MinimumSeed contains the starting values for the minimization produced by the SeedGenerator.
Definition: MinimumSeed.h:31
MinimumState keeps the information (position, Gradient, 2nd deriv, etc) after one minimization step (...
Definition: MinimumState.h:29
Wrapper class to FCNBase interface used internally by Minuit.
Definition: MnFcn.h:33
unsigned int NumOfCalls() const
Definition: MnFcn.h:43
determines the relative floating point arithmetic precision.
double Eps2() const
eps2 returns 2*sqrt(eps)
API class for defining three levels of strategies: low (0), medium (1), high (>=2); acts on: Migrad (...
Definition: MnStrategy.h:27
class which holds the external user and/or internal Minuit representation of the parameters and error...
const MnMachinePrecision & Precision() const
const std::vector< double > & IntParameters() const
const MnUserTransformation & Trafo() const
virtual MinimumSeed operator()(const MnFcn &, const GradientCalculator &, const MnUserParameterState &, const MnStrategy &) const
double Estimate(const FunctionGradient &, const MinimumError &) const
Double_t x[n]
Definition: legend1.C:17
const Int_t n
Definition: legend1.C:16
VecExpr< UnaryOp< Fabs< T >, VecExpr< A, T, D >, T >, T, D > fabs(const VecExpr< A, T, D > &rhs)
VSD Structures.
Definition: StringConv.hxx:21