doc boost mp as gmp replacement

Documentation/doc/Documentation/Third_party.txt

@@ -72,23 +72,34 @@ As there is no canonical directory for where to find \boost on Windows,
 we recommend that you define the environment variable
 `BOOST_ROOT` and set it to where you have installed \boost, e.g., `C:\boost\boost_1_70_0`.
 
-\subsection thirdpartyMPFR GNU Multiple Precision Arithmetic (GMP) and GNU Multiple Precision Floating-Point Reliably (MPFR) Libraries
-<b>GMP Version 5.0.1 or later, MPFR Version 3.0.0 or later</b>
+\subsection thirdpartyMP Multi Precision Number Type Library
 
-The components \cgal, `CGAL_Core`, and `CGAL_Qt6` require
-\gmp and \mpfr which are libraries for multi precision integers and rational numbers,
-and for multi precision floating point numbers.
-
-\cgal combines floating point arithmetic with exact arithmetic
-in order to be efficient and reliable. \cgal has a built-in
-number type for that, but \gmp and \mpfr provide a faster
-solution, and we recommend using them.
+GNU Multiple Precision Arithmetic (GMP) and GNU Multiple Precision Floating-Point Reliably (MPFR) Libraries
+are libraries for multi precision integers and rational numbers, and for multi precision floating point numbers.
 
 These libraries can be obtained from <A HREF="https://gmplib.org/">`https://gmplib.org/`</A>
 and <A HREF="https://www.mpfr.org/">`https://www.mpfr.org/`</A>.
 Since Visual \cpp is not properly supported by the \gmp and \mpfr projects,
 we provide precompiled versions of \gmp and \mpfr, which can be downloaded
 from the <a href="https://github.com/CGAL/cgal/releases">assets of a release</a>.
+Version supported are <b>GMP Version 5.0.1 or later, MPFR Version 3.0.0 or later</b>.
+
+The \boost library also provides a module for multi precision integers and rational numbers:
+<A HREF="https://www.boost.org/doc/libs/release/libs/multiprecision/doc/html/index.html">\boost multiprecision</A>.
+Versions supported are <b>\boost Version 1.72 or later</b>.
+
+The components \cgal, and `CGAL_Qt6` require either \gmp and \mpfr, or \boost multiprecision
+for multi precision numbers. `CGAL_Core` requires \boost multiprecision.
+
+\cgal combines floating point arithmetic with exact arithmetic
+in order to be efficient and reliable. \cgal has a built-in
+number type for that, but previous alternatives are faster
+solutions, and we recommend using one of them.
+
+The CMake variable `CGAL_CMAKE_EXACT_NT_BACKEND` can be used to select
+the library that will be used internally for multi precision number types.
+The variable `CGAL_CMAKE_EXACT_NT_BACKEND-STRINGS` contains all the possible
+values.
 
 \section secoptional3rdpartysoftware Optional Third Party Libraries
 

Documentation/doc/Documentation/Usage.txt

@@ -36,7 +36,7 @@ Using \cgal requires a few core components to be previously installed:
 <li> a supported compiler (see Section \ref seccompilers),</li>
 <li> \ref seccmake,</li>
 <li> \ref thirdpartyBoost,</li>
-<li> \ref thirdpartyMPFR.</li>
+<li> a \ref thirdpartyMP.</li>
 </ul>
 
 Optional third-party software might be required to build examples and demos shipped with \cgal,

Documentation/doc/Documentation/windows.txt

@@ -6,7 +6,7 @@
 15.9, 16.0, 17.0 (\visualstudio 2017, 2019, and 2022).
 
 \cgal is a library that has mandatory dependencies that must be first installed:
-\ref thirdpartyBoost and \ref thirdpartyMPFR.
+\ref thirdpartyBoost and a \ref thirdpartyMP.
 
 You have two options to install \cgal and its dependencies: you can either use
 the *Vcpkg library manager*, which will automatically install an appropriate version of

Installation/CHANGES.md

@@ -13,6 +13,8 @@ Release date: June 2024
  - LLVM Clang version 15.0.7 or later (on Linux)
  - Apple Clang compiler versions 10.0.1, 12.0.5, and 15.0.0 (on macOS)
 - The minimal supported version of Boost is now 1.72.0.
+- GMP/MPFR are no longer mandatory to use CGAL, [Boost.Multiprecision](https://www.boost.org/doc/libs/1_72_0/libs/multiprecision/doc/html/index.html).
+ can be used instead.
 - The CGAL `Core` library is no longer based on GMP, but on
  [Boost.Multiprecision](https://www.boost.org/doc/libs/1_72_0/libs/multiprecision/doc/html/index.html).
  Either GMP backend or Boost backend can be used.