Class accessor

boost::histogram::indexed_range::accessor — Lightweight view to access value and index of current cell.

Synopsis

// In header: <boost/histogram/indexed.hpp>



// Lightweight view to access value and index of current cell.

class accessor {
public:
  // member classes/structs/unions

  // Array-like view into the current multi-dimensional index.

  class index_view {
  public:
    // types
    typedef unspecified              const_iterator; 
    typedef const axis::index_type & const_reference;

    // public member functions
    const_iterator begin() const noexcept;
    const_iterator end() const noexcept;
    std::size_t size() const noexcept;
    const_reference operator[](unsigned) const noexcept;
    const_reference at(unsigned) const;
  };
  // construct/copy/destruct
  accessor(iterator &) noexcept;
  accessor(const accessor &) = default;
  accessor & operator=(const accessor &);
  template<typename T> accessor & operator=(const T &);

  // public member functions
  value_reference get() const noexcept;
  value_reference operator *() const noexcept;
  value_iterator operator->() const noexcept;
  axis::index_type index(unsigned = 0) const noexcept;
  index_view indices() const noexcept;
  template<unsigned N = 0> 
    decltype(auto) bin(std::integral_constant< unsigned, N > = {}) const;
  decltype(auto) bin(unsigned) const;
  double density() const;
  bool operator<(const accessor &) noexcept;
  bool operator>(const accessor &) noexcept;
  bool operator==(const accessor &) noexcept;
  bool operator!=(const accessor &) noexcept;
  bool operator<=(const accessor &) noexcept;
  bool operator>=(const accessor &) noexcept;
  template<typename U> bool operator<(const U &) const noexcept;
  template<typename U> bool operator>(const U &) const noexcept;
  template<typename U> bool operator==(const U &) const noexcept;
  template<typename U> bool operator!=(const U &) const noexcept;
  template<typename U> bool operator<=(const U &) const noexcept;
  template<typename U> bool operator>=(const U &) const noexcept;
  operator value_type() const noexcept;
};

Description

The methods provide access to the current cell indices and bins. It acts like a pointer to the cell value, and in a limited way also like a reference. To interoperate with the algorithms of the standard library, the accessor is implicitly convertible to a cell value. Assignments and comparisons are passed through to the cell. An accessor is coupled to its parent indexed_range::iterator. Moving the parent iterator forward also updates the linked accessor. Accessors are not copyable. They cannot be stored in containers, but indexed_range::iterator can be stored.

`accessor` public construct/copy/destruct

```
accessor(iterator & i) noexcept;
```
```
accessor(const accessor &) = default;
```

accessor & operator=(const accessor & o);

template<typename T> accessor & operator=(const T & x);

`accessor` public member functions

```
value_reference get() const noexcept;
```
Returns the cell reference.

value_reference operator *() const noexcept;

Returns the cell reference.

value_iterator operator->() const noexcept;

Access fields and methods of the cell object.

axis::index_type index(unsigned d = 0) const noexcept;

Access current index.

Parameters:

`d`	axis dimension.

```
index_view indices() const noexcept;
```
Access indices as an iterable range.

template<unsigned N = 0> 
  decltype(auto) bin(std::integral_constant< unsigned, N > = {}) const;

Access current bin.

Template Parameters:

`N`	axis dimension.

```
decltype(auto) bin(unsigned d) const;
```
Access current bin.

Parameters:

d

axis dimension.
```
double density() const;
```
Computes density in current cell.
The density is computed as the cell value divided by the product of bin widths. Axes without bin widths, like axis::category, are treated as having unit bin with.

bool operator<(const accessor & o) noexcept;

bool operator>(const accessor & o) noexcept;

bool operator==(const accessor & o) noexcept;

bool operator!=(const accessor & o) noexcept;

bool operator<=(const accessor & o) noexcept;

bool operator>=(const accessor & o) noexcept;

template<typename U> bool operator<(const U & o) const noexcept;

template<typename U> bool operator>(const U & o) const noexcept;

template<typename U> bool operator==(const U & o) const noexcept;

template<typename U> bool operator!=(const U & o) const noexcept;

template<typename U> bool operator<=(const U & o) const noexcept;

template<typename U> bool operator>=(const U & o) const noexcept;

```
operator value_type() const noexcept;
```

Boost C++ Libraries

Class accessor

Synopsis

Description

accessor public construct/copy/destruct

accessor public member functions

`accessor` public construct/copy/destruct

`accessor` public member functions