/usr/include/root/Math/RootFinder.h is in libroot-math-mathcore-dev 5.34.30-0ubuntu8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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// Authors: L. Moneta, A. Zsenei 08/2005
/**********************************************************************
* *
* Copyright (c) 2004 ROOT Foundation, CERN/PH-SFT *
* *
* This library is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License *
* as published by the Free Software Foundation; either version 2 *
* of the License, or (at your option) any later version. *
* *
* This library is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this library (see file COPYING); if not, write *
* to the Free Software Foundation, Inc., 59 Temple Place, Suite *
* 330, Boston, MA 02111-1307 USA, or contact the author. *
* *
**********************************************************************/
// Header file for class RootFinder
//
// Created by: moneta at Sun Nov 14 16:59:55 2004
//
// Last update: Sun Nov 14 16:59:55 2004
//
#ifndef ROOT_Math_RootFinder
#define ROOT_Math_RootFinder
#ifndef ROOT_Math_IFunctionfwd
#include "Math/IFunctionfwd.h"
#endif
#ifndef ROOT_Math_IRootFinderMethod
#include "Math/IRootFinderMethod.h"
#endif
/**
@defgroup RootFinders One-dimensional Root-Finding algorithms
Various implementation esists in MathCore and MathMore
The user interacts with a proxy class ROOT::Math::RootFinder which creates behing
the chosen algorithms which are implemented using the ROOT::Math::IRootFinderMethod interface
@ingroup NumAlgo
*/
namespace ROOT {
namespace Math {
//_____________________________________________________________________________________
/**
User Class to find the Root of one dimensional functions.
The GSL Methods are implemented in MathMore and they are loaded automatically
via the plug-in manager
The possible types of Root-finding algorithms are:
<ul>
<li>Root Bracketing Algorithms which do not require function derivatives
<ol>
<li>RootFinder::kBRENT (default method implemented in MathCore)
<li>RootFinder::kGSL_BISECTION
<li>RootFinder::kGSL_FALSE_POS
<li>RootFinder::kGSL_BRENT
</ol>
<li>Root Finding Algorithms using Derivatives
<ol>
<li>RootFinder::kGSL_NEWTON
<li>RootFinder::kGSL_SECANT
<li>RootFinder::kGSL_STEFFENSON
</ol>
</ul>
This class does not cupport copying
@ingroup RootFinders
*/
class RootFinder {
public:
enum EType { kBRENT, // Methods from MathCore
kGSL_BISECTION, kGSL_FALSE_POS, kGSL_BRENT, // GSL Normal
kGSL_NEWTON, kGSL_SECANT, kGSL_STEFFENSON // GSL Derivatives
};
/**
Construct a Root-Finder algorithm
*/
RootFinder(RootFinder::EType type = RootFinder::kBRENT);
virtual ~RootFinder();
private:
// usually copying is non trivial, so we make this unaccessible
RootFinder(const RootFinder & ) {}
RootFinder & operator = (const RootFinder & rhs)
{
if (this == &rhs) return *this; // time saving self-test
return *this;
}
public:
bool SetMethod(RootFinder::EType type = RootFinder::kBRENT);
/**
Provide to the solver the function and the initial search interval [xlow, xup]
for algorithms not using derivatives (bracketing algorithms)
The templated function f must be of a type implementing the \a operator() method,
<em> double operator() ( double x ) </em>
Returns non zero if interval is not valid (i.e. does not contains a root)
*/
bool SetFunction( const IGenFunction & f, double xlow, double xup) {
return fSolver->SetFunction( f, xlow, xup);
}
/**
Provide to the solver the function and an initial estimate of the root,
for algorithms using derivatives.
The templated function f must be of a type implementing the \a operator()
and the \a Gradient() methods.
<em> double operator() ( double x ) </em>
Returns non zero if starting point is not valid
*/
bool SetFunction( const IGradFunction & f, double xstart) {
return fSolver->SetFunction( f, xstart);
}
template<class Function, class Derivative>
bool Solve(Function &f, Derivative &d, double start,
int maxIter = 100, double absTol = 1E-8, double relTol = 1E-10);
template<class Function>
bool Solve(Function &f, double min, double max,
int maxIter = 100, double absTol = 1E-8, double relTol = 1E-10);
/**
Compute the roots iterating until the estimate of the Root is within the required tolerance returning
the iteration Status
*/
bool Solve( int maxIter = 100, double absTol = 1E-8, double relTol = 1E-10) {
return fSolver->Solve( maxIter, absTol, relTol );
}
/**
Return the number of iteration performed to find the Root.
*/
int Iterations() const {
return fSolver->Iterations();
}
/**
Perform a single iteration and return the Status
*/
int Iterate() {
return fSolver->Iterate();
}
/**
Return the current and latest estimate of the Root
*/
double Root() const {
return fSolver->Root();
}
/**
Return the status of the last estimate of the Root
= 0 OK, not zero failure
*/
int Status() const {
return fSolver->Status();
}
/**
Return the current and latest estimate of the lower value of the Root-finding interval (for bracketing algorithms)
*/
/* double XLower() const { */
/* return fSolver->XLower(); */
/* } */
/**
Return the current and latest estimate of the upper value of the Root-finding interval (for bracketing algorithms)
*/
/* double XUpper() const { */
/* return fSolver->XUpper(); */
/* } */
/**
Get Name of the Root-finding solver algorithm
*/
const char * Name() const {
return fSolver->Name();
}
protected:
private:
IRootFinderMethod* fSolver; // type of algorithm to be used
};
} // namespace Math
} // namespace ROOT
#ifndef ROOT_Math_WrappedFunction
#include "Math/WrappedFunction.h"
#endif
#ifndef ROOT_Math_Functor
#include "Math/Functor.h"
#endif
template<class Function, class Derivative>
bool ROOT::Math::RootFinder::Solve(Function &f, Derivative &d, double start,
int maxIter, double absTol, double relTol)
{
if (!fSolver) return false;
ROOT::Math::GradFunctor1D wf(f, d);
bool ret = fSolver->SetFunction(wf, start);
if (!ret) return false;
return Solve(maxIter, absTol, relTol);
}
template<class Function>
bool ROOT::Math::RootFinder::Solve(Function &f, double min, double max,
int maxIter, double absTol, double relTol)
{
if (!fSolver) return false;
ROOT::Math::WrappedFunction<Function &> wf(f);
bool ret = fSolver->SetFunction(wf, min, max);
if (!ret) return false;
return Solve(maxIter, absTol, relTol);
}
#endif /* ROOT_Math_RootFinder */
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