utility.hpp

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//This file is part of Bertini 2.
//
//bertini2/system/start/utility.hpp 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 3 of the License, or
//(at your option) any later version.
//
//bertini2/system/start/utility.hpp 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 bertini2/system/start/utility.hpp.  If not, see <http://www.gnu.org/licenses/>.
//
// Copyright(C) 2015 - 2021 by Bertini2 Development Team
//
// See <http://www.gnu.org/licenses/> for a copy of the license, 
// as well as COPYING.  Bertini2 is provided with permitted 
// additional terms in the b2/licenses/ directory.
 
// individual authors of this file include:
// silviana amethyst, university of wisconsin - eau claire

 
#ifndef BERTINI_START_SYSTEM_UTILITIES_HPP
#define BERTINI_START_SYSTEM_UTILITIES_HPP
 
 
 
namespace bertini{
 

    template <typename T>
    std::vector<T> IndexToSubscript(T index, std::vector<T> const& dimensions)
    {
 
        std::vector< T > subscripts(dimensions.size());//for forming a subscript from an index
 
        std::vector<T> k(dimensions.size(),1);
        for (int ii = 0; ii < dimensions.size()-1; ++ii)
          k[ii+1] = k[ii]*dimensions[ii];
 
 
        if (index >= k.back()*dimensions.back())
          throw std::out_of_range("in IndexToSubscript, index exceeds max based on dimension sizes");
 
 
        for (int ii = dimensions.size()-1; ii >= 0; --ii)
        {
          T I = index%k[ii];
          T J = (index - I) / k[ii];
          subscripts[ii] = J;
          index = I;
        }
 
        return subscripts;
      }
 
      
 
} // re: namespace bertini
 
 
 
 
#endif