Added segments printing.

/***************************************************************************

                          SegmentsPrinting.h -  description

                             -------------------

    begin                : Apr 1, 2021

    copyright            : (C) 2021 by Tomas Oberhuber

    email                : tomas.oberhuber@fjfi.cvut.cz

 ***************************************************************************/

/* See Copyright Notice in tnl/Copyright */

#pragma once

#include <iostream>

#include <TNL/Containers/Array.h>

namespace TNL {

   namespace Algorithms {

      namespace Segments {

template< typename Segments >

std::ostream& printSegments( const Segments& segments, std::ostream& str )

{

   using IndexType = typename Segments::IndexType;

   using DeviceType = typename Segments::DeviceType;

   auto segmentsCount = segments.getSegmentsCount();

   str << " [";

   for( IndexType segmentIdx = 0; segmentIdx < segmentsCount; segmentIdx++ )

   {

      auto segmentSize = segments.getSegmentSize( segmentIdx );

      str << " " << segmentSize;

      if( segmentIdx < segmentsCount )

         str << ",";

   }

   str << " ] " << std::endl;

   return str;

}

template< typename Segments,

          typename Fetch >

std::ostream& printSegments( const Segments& segments, Fetch&& fetch, std::ostream& str )

{

   using IndexType = typename Segments::IndexType;

   using DeviceType = typename Segments::DeviceType;

   using ValueType = decltype( fetch( IndexType() ) );

   TNL::Containers::Array< ValueType, DeviceType, IndexType > aux( 1 );

   auto view = segments.getConstView();

   for( IndexType segmentIdx = 0; segmentIdx < segments.getSegmentsCount(); segmentIdx++ )

   {

      str << "Seg. " << segmentIdx << ": [ ";

      auto segmentSize = segments.getSegmentSize( segmentIdx );

      for( IndexType localIdx = 0; localIdx < segmentSize; localIdx++ )

      {

         aux.forAllElements( [=] __cuda_callable__ ( IndexType elementIdx, double& v ) mutable {

            v = fetch( view.getGlobalIndex( segmentIdx, localIdx ) );

         } );

         auto value = aux.getElement( 0 );

         str << value;

         if( localIdx < segmentSize - 1 )

            str << ", ";

      }

      str << " ] " << std::endl;

   }

   return str;

}

      } // namespace Segments

   } // namespace Algorithms

} // namespace TNL