root/Math/PdfFuncMathMore.h

0001 // @(#)root/mathmore:$Id$
0002 // Authors: L. Moneta, A. Zsenei   08/2005
0003
0004  /**********************************************************************
0005   *                                                                    *
0006   * Copyright (c) 2004 ROOT Foundation,  CERN/PH-SFT                   *
0007   *                                                                    *
0008   * This library is free software; you can redistribute it and/or      *
0009   * modify it under the terms of the GNU General Public License        *
0010   * as published by the Free Software Foundation; either version 2     *
0011   * of the License, or (at your option) any later version.             *
0012   *                                                                    *
0013   * This library is distributed in the hope that it will be useful,    *
0014   * but WITHOUT ANY WARRANTY; without even the implied warranty of     *
0015   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU   *
0016   * General Public License for more details.                           *
0017   *                                                                    *
0018   * You should have received a copy of the GNU General Public License  *
0019   * along with this library (see file COPYING); if not, write          *
0020   * to the Free Software Foundation, Inc., 59 Temple Place, Suite      *
0021   * 330, Boston, MA 02111-1307 USA, or contact the author.             *
0022   *                                                                    *
0023   **********************************************************************/
0024
0025
0026 #ifndef ROOT_Math_PdfFuncMathMore
0027 #define ROOT_Math_PdfFuncMathMore
0028
0029 namespace ROOT {
0030    namespace Math {
0031
0032
0033   /**
0034
0035   Probability density function of the non central \f$\chi^2\f$ distribution with \f$r\f$
0036   degrees of freedom and the noon-central parameter \f$\lambda\f$
0037
0038   \f[ p_r(x) = \frac{1}{\Gamma(r/2) 2^{r/2}} x^{r/2-1} e^{-x/2} \f]
0039
0040   for \f$x \geq 0\f$.
0041   For detailed description see
0042   <A HREF="http://mathworld.wolfram.com/NoncentralChi-SquaredDistribution.html">
0043   Mathworld</A>.
0044
0045   @ingroup PdfFunc
0046
0047   */
0048
0049   double noncentral_chisquared_pdf(double x, double r, double lambda);
0050
0051    }  //end namespace Math
0052 } // end namespace ROOT
0053
0054
0055 // make a fake class to auto-load functions from MathMore
0056
0057 namespace ROOT {
0058    namespace Math {
0059
0060       class MathMoreLib {
0061
0062       public:
0063
0064          // adding this method with force the auto-loading of the library
0065          static void Load();
0066       };
0067
0068       typedef MathMoreLib MathMoreLibrary;
0069    }
0070
0071 }
0072
0073
0074
0075 #endif  // ROOT_Math_PdfFuncMathMore