12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697 |
- [/
- Copyright Hans Dembinski 2018 - 2019.
- Distributed under the Boost Software License, Version 1.0.
- (See accompanying file LICENSE_1_0.txt or copy at
- https://www.boost.org/LICENSE_1_0.txt)
- ]
- [section:Accumulator Accumulator]
- An [*Accumulator] is a functor which consumes the argument to update some internal state. The state can be read with member functions or free functions. Must be [@https://en.cppreference.com/w/cpp/named_req/DefaultConstructible DefaultConstructible], [@https://en.cppreference.com/w/cpp/named_req/CopyConstructible CopyConstructible], and [@https://en.cppreference.com/w/cpp/named_req/CopyAssignable CopyAssignable].
- [heading Required features]
- * `A` is a type meeting the requirements of [*Accumulator]
- * `a` and `b` are values of type `A`
- * `ts...` is a pack of values of arbitrary types
- [table Valid expressions
- [[Expression] [Returns] [Semantics, Pre/Post-conditions]]
- [
- [`a(ts...)` or `++a`]
- []
- [
- Either a call operator accepting a fixed number of arguments must be implemented, or the pre-increment operator. The call operator may not be templated and not overloaded, except to support weights as described under optional features.
- ]
- ]
- [
- [`a == b`]
- [`bool`]
- [
- Returns `true` if all state variables compare equal. Otherwise returns `false`.
- ]
- ]
- [
- [`a != b`]
- [`bool`]
- [
- Must be implemented if `a == b` is implemented and must be equal to `!(a == b)`.
- ]
- ]
- ]
- [heading Optional features]
- * `A` is a type meeting the requirements of [*Accumulator]
- * `a` and `b` are values of type `A`
- * `w` is a value of type [classref boost::histogram::weight_type], where `T` is a number type
- * `ts...` is a pack of values of arbitrary types
- * `v` is a number value (integral or floating point)
- [table Valid expressions
- [[Expression] [Return] [Semantics, Pre/Post-conditions]]
- [
- [`a += v` or `a(w, ts...)`]
- []
- [
- Does a weighted fill of the accumulator. Use this to implement weight support for an accumulator that is normally filled with `++a` or `a(ts...)`, respectively. Only the corresponding matching form may be implemented: `a += v` for `++a`, `a(w, ts...)` for `a(ts...)`. The implementations may not be templated and not overloaded.
- ]
- ]
- [
- [`a += b`]
- [`A&`]
- [
- Adds a second accumulator `b` of type `A`. The result must be the same as if `a` had been filled with all arguments of `b`.
- ]
- ]
- [
- [`a *= x`]
- [`A&`]
- [
- Scales the accumulator state by the real value `x`. The result must be the same as if `a` had been filled with all arguments scaled by `x`.
- ]
- ]
- [
- [`os << a`]
- [`std::basic_ostream<CharT, Traits>&`]
- [
- `os` is a value of type `std::basic_ostream<CharT, Traits>`. Streams a text representation of the axis. May not mutate `a`.
- ]
- ]
- [
- [`a.serialize(ar, n)`]
- []
- [
- `ar` is a value of an archive with Boost.Serialization semantics and `n` is an unsigned integral value. Saves to the archive or loads serialized state from the archive. The version number `n` is the stored version when the object is loaded or the current version when the object is saved.
- ]
- ]
- ]
- [heading Models]
- * [classref boost::histogram::accumulators::sum]
- * [classref boost::histogram::accumulators::weighted_sum]
- * [classref boost::histogram::accumulators::mean]
- * [classref boost::histogram::accumulators::weighted_mean]
- [endsect]
|