File indexing completed on 2024-05-12 03:41:58

 /*************************************************************************************
  *  Copyright (C) 2022 Aleix Pol Gonzalez <aleixpol@kde.org>                         *
  *  Copyright (C) 2022 Stephen Swanson <stephen.swanson@mailbox.org>                 *
  *                                                                                   *
  *  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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA   *
  *************************************************************************************/
 
 #include "combinatronics.h"
 
 #include <QCoreApplication>
 
 #include "expression.h"
 #include "list.h"
 #include "value.h"
 
 using namespace Analitza;
 
 const QString CombinationCommand::id = QStringLiteral("comb");
 const ExpressionType CombinationCommand::type = ExpressionType(ExpressionType::Lambda)
                                         .addParameter(ExpressionType::Value)
                                         .addParameter(ExpressionType::Value)
                                         .addParameter(ExpressionType::Value);
 
 Expression CombinationCommand::operator()(const QList<Expression>& args)
 {
     const auto a = args.constFirst().toReal().intValue();
     const auto b = args.constLast().toReal().intValue();
 
     // a=n b=r
     uint n_factorial=1;
     for(int i=a; i>1.; i--) {
         n_factorial*=floor(i);
     }
     uint r_factorial=1;
     for(int i=b; i>1.; i--) {
         r_factorial*=floor(i);
     }
     uint rn = a - b;
     uint rn_factorial=1;
     for(int i=rn; i>1.; i--) {
         rn_factorial*=floor(i);
     }
     uint res = n_factorial / (r_factorial * rn_factorial);
     return Expression(Cn(res));
 }
 
 const QString PermutationCommand::id = QStringLiteral("perm");
 const ExpressionType PermutationCommand::type = ExpressionType(ExpressionType::Lambda)
                                         .addParameter(ExpressionType::Value)
                                         .addParameter(ExpressionType::Value)
                                         .addParameter(ExpressionType::Value);
 
 Expression PermutationCommand::operator()(const QList<Expression>& args)
 {
     const auto a = args.constFirst().toReal().value();
     const auto b = args.constLast().toReal().intValue();
 
     // a=n b=r
     if (b > a) {
         return Expression(Cn(0));
     } else {
         uint n_factorial=1;
         for(int i=a; i>1.; i--) {
             n_factorial*=floor(i);
         }
         uint rn = a - b;
         uint rn_factorial=1;
         for(int i=rn; i>1.; i--) {
             rn_factorial*=floor(i);
         }
         uint res = n_factorial / rn_factorial;
         return Expression(Cn(res));
     }
 }