musrfit/src/external/libZFRelaxation/ZFRelaxation.cpp

74 lines
3.6 KiB
C++

/***************************************************************************
ZFRelaxation.cpp
Author: Bastian M. Wojek
$Id$
***************************************************************************/
/***************************************************************************
* Copyright (C) 2009 by Bastian M. Wojek *
* *
* *
* 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. *
***************************************************************************/
#define TWO_PI 6.28318530717958623
#define DEG_TO_RAD 0.0174532925199432955
#include "ZFRelaxation.h"
#include <cassert>
#include <cmath>
#include <vector>
using namespace std;
ClassImp(ZFMagGss)
ClassImp(ZFMagExp)
//--------------------------------------------------------------------------
// ZFMagGss::operator()
//--------------------------------------------------------------------------
/**
* <p>Method returning the function value at a given time for a given set of parameters.
*
* \param t time \htmlonly (&mu;s) \endhtmlonly \latexonly ($\mu\mathrm{s}$) \endlatexonly
* \param par parameters [\htmlonly &alpha; (1), &nu; (MHz), &sigma;<sub>T</sub>; (&mu;s<sup>-1</sup>), &sigma;<sub>L</sub>; (&mu;s<sup>-1</sup>)\endhtmlonly \latexonly $\alpha~(1)$, $\nu~(\mathrm{MHz})$, $\sigma_{\mathrm{T}}~(\mu\mathrm{s}^{-1})$, $\sigma_{\mathrm{L}}~(\mu\mathrm{s}^{-1})$ \endlatexonly]
*/
double ZFMagGss::operator()(double t, const vector<double> &par) const {
assert(par.size()==4);
double w(TWO_PI * par[1]), sst(par[2]*par[2]*t);
return par[0] * (cos(w*t) - sst/w*sin(w*t)) * exp(-0.5*sst*t) + (1.0-par[0]) * exp(-0.5*par[3]*par[3]*t*t);
}
//--------------------------------------------------------------------------
// ZFMagExp::operator()
//--------------------------------------------------------------------------
/**
* <p>Method returning the function value at a given time for a given set of parameters.
*
* \param t time \htmlonly (&mu;s) \endhtmlonly \latexonly ($\mu\mathrm{s}$) \endlatexonly
* \param par parameters [\htmlonly &alpha; (1), &nu; (MHz), <i>a</i><sub>T</sub>; (&mu;s<sup>-1</sup>), <i>a</i><sub>L</sub>; (&mu;s<sup>-1</sup>)\endhtmlonly \latexonly $\alpha~(1)$, $\nu~(\mathrm{MHz})$, $a_{\mathrm{T}}~(\mu\mathrm{s}^{-1})$, $a_{\mathrm{L}}~(\mu\mathrm{s}^{-1})$ \endlatexonly]
*/
double ZFMagExp::operator()(double t, const vector<double> &par) const {
assert(par.size()==4);
double w(TWO_PI * par[1]);
return par[0] * (cos(w*t) - par[2]/w*sin(w*t)) * exp(-par[2]*t) + (1.0-par[0]) * exp(-par[3]*t);
}