integration.h

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/***************************************************************************
 *
 * Authors:     Javier Rodrguez Falces (jrodriguez@cnb.csic.es)
 *
 * Unidad de  Bioinformatica of Centro Nacional de Biotecnologia , CSIC
 *
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307  USA
 *
 *  All comments concerning this program package may be sent to the
 *  e-mail address 'xmipp@cnb.csic.es'
 ***************************************************************************/

#ifndef CORE_INTEGRATION_H
#define CORE_INTEGRATION_H

double integrateNewtonCotes(double(*f)(double), double a, double b, int N);

class doubleFunction
{
public:
    virtual double operator()()=0; // pure virtual function
    virtual ~doubleFunction()
    {} // virtual destructor
};

class Trapeze: public doubleFunction
{
    double s;
    doubleFunction& func; // the generic function to be NumericalIntegration
    double a; // integral limits
    double b; // integral limits
    double& x; // integration variable
    double EPS; // desired accuracy
    int JMAX; // 2**(JMAX) = max number of func. evaluation

public:
    // Overloads pure virtual function.
    virtual double operator()();

    double operator()(double min, double max,
                      double precision = 1.0e-7, int max_iter = 20)
    {
        a = min;
        b = max;
        EPS = precision;
        JMAX = max_iter;
        return (*this)();
    }

    Trapeze(doubleFunction& f, double& Var, double min, double max,
            double precision = 1.0e-7, int max_iter = 20) : func(f), x(Var)
    {
        a = min;
        b = max;
        EPS = precision;
        JMAX = max_iter;
    }

    double Trap(int n);
};

class Romberg : public doubleFunction
{
    double s;
    doubleFunction& func; // the function to be Numerical_interationd
    double a; // integral limits
    double b; // integral limits
    double& x; // integration variable
    double EPS; // desired accuracy

public:
    // TODO Document
    virtual double operator()();

    double operator()(double min, double max, double precision = 1.0e-7)
    {
        a = min;
        b = max;
        EPS = precision;
        return (*this)();
    }

    Romberg(doubleFunction& f, double& Var, double min, double max,
            double precision = 1.0e-7) : func(f), x(Var)
    {
        s = 0.0;
        a = min;
        b = max;
        EPS = precision;
    }

    double midpnt(int n);
};
#endif