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class ROOT::Math::GSLMinimizer1D: public ROOT::Math::IMinimizer1D



Minimizer for arbitrary one dimensional functions.

Implemented using GSL, for detailed description see:
<A HREF="http://www.gnu.org/software/gsl/manual/html_node/One-dimensional-Minimization.html">GSL online doc</A>

The algorithms uspported are only bracketing algorithm which do not use derivatives information.
The algorithms which can be choosen at construction time are  GOLDENSECTION, whic is the simplest method
but the slowest and BRENT (the default one) which combines the golden section with a parabolic interpolation.


This class does not support copying
@ingroup Min1D

Function Members (Methods)

public:
virtual~GSLMinimizer1D()
virtual doubleFValLower() const
virtual doubleFValMinimum() const
virtual doubleFValUpper() const
ROOT::Math::GSLMinimizer1DGSLMinimizer1D(ROOT::Math::Minim1D::Type type = Minim1D::kBRENT)
intIterate()
virtual intIterations() const
virtual boolMinimize(int maxIter, double absTol, double relTol)
virtual const char*Name() const
voidSetFunction(ROOT::Math::GSLFuncPointer f, void* params, double xmin, double xlow, double xup)
virtual intStatus() const
static intTestInterval(double xlow, double xup, double epsAbs, double epsRel)
virtual doubleXLower() const
virtual doubleXMinimum() const
virtual doubleXUpper() const

Data Members

private:
ROOT::Math::GSLFunctionWrapper*fFunction
boolfIsSet
intfIter
doublefLow
doublefMin
ROOT::Math::GSL1DMinimizerWrapper*fMinimizer
intfStatusstatus of last minimization (==0 ok =1 failed)
doublefUp
doublefXlow
doublefXmin
doublefXup

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

explicit GSLMinimizer1D(Minim1D::Type type=Minim1D::kBRENT)
         Construct the minimizer passing the minimizer type using the Minim1D::Algorithm enumeration

virtual ~GSLMinimizer1D()
         Destructor: free allocated resources

GSLMinimizer1D(const GSLMinimizer1D &)
 usually copying is non trivial, so we make this unaccessible
void SetFunction( const UserFunc & f, double xmin, double xlow, double xup)
          Set, or reset, minimizer to use the function f and the initial search interval [xlow, xup], with a guess for the location of the minimum xmin.
          The condition : \f$ f(xlow) > f(xmin) < f(xup)\f$  must be satisfied

int Iterate()
          Perform a minimizer iteration and
          if an unexepcted problem occurr then an error code will be returned

double XMinimum() const
          Return current estimate of the position of the minimum

double XLower() const
         Return current lower bound of the minimization interval

double XUpper() const
         Return current upper bound of the minimization interval

double FValMinimum() const
          Return function value at current estimate of the minimum

double FValLower() const
         Return function value at current lower bound of the minimization interval

double FValUpper() const
         Return function value at current upper bound of the minimization interval

bool Minimize(int maxIter, double absTol, double relTol)
         Find minimum position iterating until convergence specified by the absolute and relative tolerance or
         the maximum number of iteration is reached
         Return true is result is successfull
         \@param maxIter maximum number of iteration
         \@param absTol desired absolute error in the minimum position
         \@param absTol desired relative error in the minimum position

int Iterations() const
         Return number of iteration used to find minimum

int Status() const
         Return status of last minimization

{ return fStatus; }
const char * Name() const
         Return name of minimization algorithm

int TestInterval(double xlow, double xup, double epsAbs, double epsRel)
         Test convergence of the interval.
         The test returns success if
         \f[
         |x_{min}-x_{truemin}| < epsAbs + epsRel *x_{truemin}
         \f]