Stokhos_SparseArray.hpp

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// @HEADER
// *****************************************************************************
//                           Stokhos Package
//
// Copyright 2009 NTESS and the Stokhos contributors.
// SPDX-License-Identifier: BSD-3-Clause
// *****************************************************************************
// @HEADER

#ifndef STOKHOS_SPARSEARRAY_HPP
#define STOKHOS_SPARSEARRAY_HPP

// disable clang warnings
#if defined (__clang__) && !defined (__INTEL_COMPILER)
#pragma clang system_header
#endif

#include <algorithm>
#include "Teuchos_Array.hpp"

namespace Stokhos {

  template <typename index_iterator, typename value_iterator> 
  struct SparseArrayIterator;

  template <typename index_iterator, typename value_iterator> 
  struct SparseArrayReverseIterator;
    
  template <typename ordinal_type, typename val_type>
  struct SparseArray {

    Teuchos::Array<ordinal_type> indices;

    Teuchos::Array<val_type> values;
    
    ordinal_type size() const { return indices.size(); }
    
    void resize(ordinal_type sz) {
      indices.resize(sz);
      values.resize(sz);
    }
    
    typedef typename Teuchos::Array<ordinal_type>::const_iterator index_const_iterator;
    typedef typename Teuchos::Array<val_type>::const_iterator value_const_iterator;
    typedef SparseArrayIterator<index_const_iterator, value_const_iterator> const_iterator;
    typedef SparseArrayReverseIterator<index_const_iterator, value_const_iterator> const_reverse_iterator;
    
    const_iterator begin() const { 
      return const_iterator(indices.begin(), values.begin()); 
    }

    const_iterator end() const { 
      return const_iterator(indices.end(), values.end()); 
    }

    const_reverse_iterator rbegin() const { 
      return const_reverse_iterator(end()); 
    }

    const_reverse_iterator rend() const { 
      return const_reverse_iterator(begin()); 
    }


    const_iterator find(ordinal_type i) const {
      const_iterator it = std::lower_bound(begin(), end(), i);
      bool found = it != end() && *it == i;
      if (found)
  return it;
      else
  return end();
    }

  };


  template <typename index_iterator_type, typename value_iterator_type>
  class SparseArrayIterator : 
    public std::iterator<
      std::bidirectional_iterator_tag, 
      typename std::iterator_traits<index_iterator_type>::value_type,
      typename std::iterator_traits<index_iterator_type>::difference_type,
      typename std::iterator_traits<index_iterator_type>::pointer,
      typename std::iterator_traits<index_iterator_type>::reference > {
  public:

    typedef std::iterator<
      std::bidirectional_iterator_tag, 
      typename std::iterator_traits<index_iterator_type>::value_type,
      typename std::iterator_traits<index_iterator_type>::difference_type,
      typename std::iterator_traits<index_iterator_type>::pointer,
      typename std::iterator_traits<index_iterator_type>::reference > base_type;
    typedef typename base_type::iterator_category iterator_category;
    typedef typename base_type::value_type value_type;
    typedef typename base_type::difference_type difference_type;
    typedef typename base_type::reference reference;
    typedef typename base_type::pointer pointer;
    typedef typename std::iterator_traits<value_iterator_type>::reference value_reference;

    SparseArrayIterator() : index_iterator(), value_iterator() {}
    
    SparseArrayIterator(index_iterator_type index_it, 
      value_iterator_type value_it) :
      index_iterator(index_it), value_iterator(value_it) {}
    
    bool operator==(const SparseArrayIterator& it) const {
      return index_iterator == it.index_iterator && 
  value_iterator == it.value_iterator;
    }
    
    bool operator!=(const SparseArrayIterator& it) const {
      return index_iterator != it.index_iterator || 
  value_iterator != it.value_iterator;
    }
    
    reference
    operator*() const {
      return *index_iterator;
    }
    
    pointer
    operator->() const {
      return index_iterator.operator->();
    }
    
    SparseArrayIterator& operator++() {
  index_iterator++;
  value_iterator++;
      return *this;
    }
    
    SparseArrayIterator operator++(int) {
      SparseArrayIterator tmp(*this);
      ++(*this);
      return tmp;
    }

    SparseArrayIterator& operator--() {
  index_iterator--;
  value_iterator--;
      return *this;
    }
    
    SparseArrayIterator operator--(int) {
      SparseArrayIterator tmp(*this);
      --(*this);
      return tmp;
    }

    bool operator<(const SparseArrayIterator& b) const {
      return index_iterator < b.index_iterator && 
  value_iterator < b.value_iterator;
    }
    
    value_reference value() const {
      return *value_iterator;
    }
    
  protected:
    
    index_iterator_type index_iterator;

    value_iterator_type value_iterator;
    
  };

  template <typename index_iterator_type, typename value_iterator_type>
  class SparseArrayReverseIterator : 
    public std::reverse_iterator< SparseArrayIterator<index_iterator_type,
                  value_iterator_type> > {
  public:

    typedef SparseArrayIterator<index_iterator_type, value_iterator_type> iterator_type;
    typedef std::reverse_iterator<iterator_type> base_type;
    typedef typename base_type::iterator_category iterator_category;
    typedef typename base_type::value_type value_type;
    typedef typename base_type::difference_type difference_type;
    typedef typename base_type::reference reference;
    typedef typename base_type::pointer pointer;
    typedef typename std::iterator_traits<value_iterator_type>::reference value_reference;

    SparseArrayReverseIterator() : base_type() {}
    
    SparseArrayReverseIterator(iterator_type it) : base_type(it) {}
    
    value_reference value() const {
      iterator_type tmp = this->base();
      --tmp;
      return tmp.value();
    }
    
  };

} // namespace Stokhos

#endif // STOKHOS_SPARSEARRAY_HPP