Imported Upstream version 1.72.0

[platform/upstream/boost.git] / libs / histogram / doc / concepts / Accumulator.qbk

diff --git a/libs/histogram/doc/concepts/Accumulator.qbk b/libs/histogram/doc/concepts/Accumulator.qbk
index ff6df8b..05ffa18 100644 (file)
--- a/libs/histogram/doc/concepts/Accumulator.qbk
+++ b/libs/histogram/doc/concepts/Accumulator.qbk
@@ -1,3 +1,10 @@
+[/
+            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].
@@ -6,7 +13,7 @@ An [*Accumulator] is a functor which consumes the argument to update some intern
 
 * `A` is a type meeting the requirements of [*Accumulator]
 * `a` and `b` are values of type `A`
-* `ts...` is a pack of values
+* `ts...` is a pack of values of arbitrary types
 
 [table Valid expressions
 [[Expression] [Returns] [Semantics, Pre/Post-conditions]]
@@ -14,7 +21,7 @@ An [*Accumulator] is a functor which consumes the argument to update some intern
   [`a(ts...)` or `++a`]
   []
   [
-    Either a call operator accepting a fixed number of arguments must be implemented, or the pre-increment operator.
+    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.
   ]
 ]
 [
@@ -37,10 +44,20 @@ An [*Accumulator] is a functor which consumes the argument to update some intern
 
 * `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&`]
   [
@@ -62,10 +79,10 @@ An [*Accumulator] is a functor which consumes the argument to update some intern
   ]
 ]
 [
-  [`ar & a`]
+  [`a.serialize(ar, n)`]
   []
   [
-    `ar` is a value of an archive with Boost.Serialization semantics. Serializes `a` to the archive or loads serialized state from the archive.
+    `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.
   ]
 ]
 ]