Class template count

boost::histogram::accumulators::count — Wraps a C++ arithmetic type with optionally thread-safe increments and adds.

Synopsis

// In header: <boost/histogram/accumulators/count.hpp>

template<typename ValueType, bool ThreadSafe> 
class count {
public:
  // types
  typedef ValueType          value_type;     
  typedef const value_type & const_reference;

  // construct/copy/destruct
  count();
  count(const_reference) noexcept;
  template<typename T, bool B> count(const count< T, B > &) noexcept;

  // public member functions
  count & operator++() noexcept;
  count & operator+=(const_reference) noexcept;
  count & operator+=(const count &) noexcept;
  count & operator *=(const_reference) noexcept;
  bool operator==(const count &) const noexcept;
  bool operator!=(const count &) const noexcept;
  value_type value() const noexcept;
  explicit operator value_type() const noexcept;
  template<typename Archive> void serialize(Archive &, unsigned);
  count & operator *=(const count &) noexcept;
  count operator *(const count &) const noexcept;
  count & operator/=(const count &) noexcept;
  count operator/(const count &) const noexcept;
  bool operator<(const count &) const noexcept;
  bool operator>(const count &) const noexcept;
  bool operator<=(const count &) const noexcept;
  bool operator>=(const count &) const noexcept;

  // public static functions
  static constexpr bool thread_safe() noexcept;
};

Description

This adaptor optionally uses atomic operations to make concurrent increments and additions thread-safe for the stored arithmetic value, which can be integral or floating point. For small histograms, the performance will still be poor because of False Sharing, see https://en.wikipedia.org/wiki/False_sharing for details.

Warning: Assignment is not thread-safe in this implementation, so don't assign concurrently.

This wrapper class can be used as a base class by users to add arbitrary metadata to each bin of a histogram.

When weighted samples are accumulated and high precision is required, use accumulators::sum instead (at the cost of lower performance). If a local variance estimate for the weight distribution should be computed as well (generally needed for a detailed statistical analysis), useaccumulators::weighted_sum.

Template Parameters

```
typename ValueType
```
```
bool ThreadSafe
```
Set to true to make increments and adds thread-safe.

`count` public construct/copy/destruct

```
count();
```
```
count(const_reference value) noexcept;
```
Initialize count to value and allow implicit conversion.

template<typename T, bool B> count(const count< T, B > & c) noexcept;

Allow implicit conversion from other count.

`count` public member functions

```
count & operator++() noexcept;
```
Increment count by one.

count & operator+=(const_reference value) noexcept;

Increment count by value.

count & operator+=(const count & s) noexcept;

Add another count.

count & operator *=(const_reference value) noexcept;

Scale by value.

bool operator==(const count & rhs) const noexcept;

bool operator!=(const count & rhs) const noexcept;

```
value_type value() const noexcept;
```
Return count.

explicit operator value_type() const noexcept;

template<typename Archive> void serialize(Archive & ar, unsigned);

count & operator *=(const count & rhs) noexcept;

count operator *(const count & rhs) const noexcept;

count & operator/=(const count & rhs) noexcept;

count operator/(const count & rhs) const noexcept;

bool operator<(const count & rhs) const noexcept;

bool operator>(const count & rhs) const noexcept;

bool operator<=(const count & rhs) const noexcept;

bool operator>=(const count & rhs) const noexcept;

`count` public static functions

static constexpr bool thread_safe() noexcept;

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