On Mon, Jun 1, 2026 at 10:16 AM Jonathan Wakely <[email protected]> wrote:
> On Mon, 1 Jun 2026 at 08:24, Tomasz Kamiński <[email protected]> wrote: > > > > This implements the interface changes from > > LWG1439, "Return from densities() functions?". > > > > Due the ABI concerns, we cannot change the the element_type of member > > (_M_den, _M_cp, and _M_m) vectors, and we convert the _M_den values > > to result_type when function is invoked. However, as the usage of > > distributions with types other than float, double, and long double > > is either undefined (pre C++26) or implementaiton-defined (post C++26), > > this limitation de-fact applies to float, and long double (if it's > > different size than double). > > > > To handle above we introduce the __piecewise_distributions_storage<_Tp> > > struct, whose type nested typedef points to double in above two cases, > > and _Tp otherwise. The _StorageType is defined in terms of > > __piecewise_distributions_storage_t alias to above, and is then used > > in defintion of _M_den, _M_cp, and _M_m members. In consequence for > > extended floating point types (__float128, std::float16, ...) for which > > ABI can be changed, we store densitiees (and other values) as > result_type. > > > > To avoid symbol conflicts, the param_type::densities member functions > > are marked with "__rt" ABI tag. The corresponding members of the > > distributions are modified to invoke param_type method, and marked > > as always_inline. For consistency intervals methods are adjusted same > > way. > > > > To preserve current behavior, the operators>> load densities > > as values of _StorageType. > > > > Finally, we introduce _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS, that > > This macro is spelled PICEWISE everywhere (in the commit message, the > docs, and the code) instead of PIECEWISE. > > I haven't reviewed it properly yet, just noting that for now. > > > > revers above changes, restoring old behavior for all floating point > > types. Additionally for the users accept above ABI change, > > we introduce a macro _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES, > > that result in __piecewise_distributions_storage_t being unconditionally > > defined as _Tp, and thus adjust internal storage also for float and long > > double. > > > > libstdc++ PR/82749 > > > > libstdc++-v3/ChangeLog: > > > > * doc/xml/manual/using.xml > > (_GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS): Add entry. > > (_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES): Add entry. > > * doc/html/manual/using_macros.html: Regenerate. > > * include/bits/random.h > > (__detail::__piecewise_distributions_storage) > > (__detail::__piecewise_distributions_storage_t) > > (piecewise_constant_distribution::_StorageType) > > (piecewise_linear_distribution::_StorageType): Define. > > (piecewise_constant_distribution::param_type::_M_den) > > (piecewise_constant_distribution::param_type::_M_cp) > > (piecewise_linear_distribution::param_type::_M_den) > > (piecewise_linear_distribution::param_type::_M_cp) > > (piecewise_linear_distribution::param_type::_M_m): Use > _StorageType > > as element type. > > (piecewise_constant_distribution::param_type::densities) > > (piecewise_linear_distribution::param_type::densities) > > [!_GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS]: Change return type > > to vector<result_type>, mark with "__rt" ABI tag, and adjust > > implementation. > > (piecewise_constant_distribution::param_type::intervals) > > (piecewise_linear_distribution::param_type::intervals): Use > > result_type alias in return type. > > (piecewise_constant_distribution::densities) > > (piecewise_linear_distribution::densities): Delegate to > param_type > > method, additional change return type and mark as always_inline > > if _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS is not defined. > > (piecewise_constant_distribution::intervals) > > (piecewise_linear_distribution::intervals): Delegate to > param_type > > method and use result_type alias in return type. > > * include/bits/random.tcc > > (operator<<(basic_ostream&, const > piecewise_constant_distribution&)) > > (operator<<(basic_ostream&, const > piecewise_linear_distribution&)): > > Parse vector of _StorageType for densities, to preserve behavior. > > * > testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors.cc: > > New test. > > * > testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors.cc: > > New test. > > * > testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_exact.cc: > > Run accessors.cc with > _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES. > > * > testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_exact.cc: > > Likewise. > > * > testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_fallback.cc: > > Run accessors.cc with _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS. > > * > testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_fallback.cc: > > Likewise. > > --- > > v2 adds also _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS, that > > reverts the changes. I plan to use it for all changes made > > to this distributions in GCC-17. > > Additionally > > * updates and add PR link to commit description > > * add accessorrs_fallback.cc tests > > * use result_type in return consistently on new path > > > > Resated *piecewise* test. Testing on x86_64-linux. > > OK for trunk? > > > > .../doc/html/manual/using_macros.html | 19 +++ > > libstdc++-v3/doc/xml/manual/using.xml | 29 ++++ > > libstdc++-v3/include/bits/random.h | 154 +++++++++++++----- > > libstdc++-v3/include/bits/random.tcc | 8 +- > > .../operators/accessors.cc | 83 ++++++++++ > > .../operators/accessors_exact.cc | 5 + > > .../operators/accessors_fallback.cc | 5 + > > .../operators/accessors.cc | 85 ++++++++++ > > .../operators/accessors_exact.cc | 5 + > > .../operators/accessors_fallback.cc | 5 + > > 10 files changed, 359 insertions(+), 39 deletions(-) > > create mode 100644 > libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors.cc > > create mode 100644 > libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_exact.cc > > create mode 100644 > libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_fallback.cc > > create mode 100644 > libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors.cc > > create mode 100644 > libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_exact.cc > > create mode 100644 > libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_fallback.cc > > > > diff --git a/libstdc++-v3/doc/html/manual/using_macros.html > b/libstdc++-v3/doc/html/manual/using_macros.html > > index f1d8492fb9e..4be2ab576dc 100644 > > --- a/libstdc++-v3/doc/html/manual/using_macros.html > > +++ b/libstdc++-v3/doc/html/manual/using_macros.html > > @@ -156,4 +156,23 @@ > > <code class="option">-fexec-charset=UTF-8</code> so might give > incorrect results > > if called from a source file that uses a non-Unicode encoding, > > especially for format strings using non-ASCII fill characters. > > + </p></dd><dt><span class="term"><code > class="code">_GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS</code></span></dt><dd><p> > > + Undefined by default. > > + When defined, the behaviour specializations of > > + <code class="code">piecewise_constant_distribution</code> and > > + <code class="code">piecewise_linear_distribution</code> for > > + their behavior to the state prior the implementation > > + of <a class="link" href=" > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82749"; target="_top"> > > + PR82749</a> (<a class="link" href=" > https://cplusplus.github.io/LWG/lwg-defects.html#1439"; target="_top"> > > + LWG1439</a>) in GCC-17. > > + </p></dd><dt><span class="term"><code > class="code">_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES</code></span></dt><dd><p> > > + Undefined by default. ABI-changing. > > + When defined, specializations of > > + <code class="code">piecewise_constant_distribution</code> and > > + <code class="code">piecewise_linear_distribution</code> with a > > + <code class="code">result_type</code> of either <code > class="code">float</code> or > > + <code class="code">long double</code> will manage their internal > state using > > + <code class="code">result_type</code> values (instead of <code > class="code">double</code>). > > + This is required for standard conformance, but is incompatible > with > > + the default implementation of those class templates > > </p></dd></dl></div></div><div class="navfooter"><hr /><table > width="100%" summary="Navigation footer"><tr><td width="40%" > align="left"><a accesskey="p" href="using_headers.html">Prev</a> </td><td > width="20%" align="center"><a accesskey="u" > href="using.html">Up</a></td><td width="40%" align="right"> <a > accesskey="n" href="using_dual_abi.html">Next</a></td></tr><tr><td > width="40%" align="left" valign="top">Headers </td><td width="20%" > align="center"><a accesskey="h" href="../index.html">Home</a></td><td > width="40%" align="right" valign="top"> Dual > ABI</td></tr></table></div></body></html> > > \ No newline at end of file > > diff --git a/libstdc++-v3/doc/xml/manual/using.xml > b/libstdc++-v3/doc/xml/manual/using.xml > > index e2e75e8fe28..1759eb5a214 100644 > > --- a/libstdc++-v3/doc/xml/manual/using.xml > > +++ b/libstdc++-v3/doc/xml/manual/using.xml > > @@ -1379,6 +1379,35 @@ g++ -Winvalid-pch -I. -include stdc++.h -H -g -O2 > hello.cc -o test.exe > > especially for format strings using non-ASCII fill characters. > > </para> > > </listitem></varlistentry> > > + > <varlistentry><term><code>_GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS</code></term> > > + <listitem> > > + <para> > > + Undefined by default. > > + When defined, the behaviour specializations of > > + <code>piecewise_constant_distribution</code> and > > + <code>piecewise_linear_distribution</code> for > > + their behavior to the state prior the implementation > > + of <link xmlns:xlink="http://www.w3.org/1999/xlink"; > > + xlink:href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82749";> > > + PR82749</link> (<link xmlns:xlink="http://www.w3.org/1999/xlink"; > > + xlink:href=" > https://cplusplus.github.io/LWG/lwg-defects.html#1439";> > > + LWG1439</link>) in GCC-17. > > + </para> > > + </listitem></varlistentry> > > + > <varlistentry><term><code>_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES</code></term> > > + <listitem> > > + <para> > > + Undefined by default. ABI-changing. > > + When defined, specializations of > > + <code>piecewise_constant_distribution</code> and > > + <code>piecewise_linear_distribution</code> with a > > + <code>result_type</code> of either <code>float</code> or > > + <code>long double</code> will manage their internal state using > > + <code>result_type</code> values (instead of <code>double</code>). > > + This is required for standard conformance, but is incompatible > with > > + the default implementation of those class templates > > + </para> > > + </listitem></varlistentry> > > </variablelist> > > > > </section> > > diff --git a/libstdc++-v3/include/bits/random.h > b/libstdc++-v3/include/bits/random.h > > index a0592a00763..6b82d1120b7 100644 > > --- a/libstdc++-v3/include/bits/random.h > > +++ b/libstdc++-v3/include/bits/random.h > > @@ -6385,6 +6385,40 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > { return !(__d1 == __d2); } > > #endif > > > > + namespace __detail > > + { > > +#ifdef _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES > > + template<typename _Tp> > > + using __piecewise_distributions_storage_t = _Tp; > While fixing the name, I noticed I have this change locally, but it wasn't included in the email. namespace __detail { -#ifdef _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES +#if defined(_GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS) + template<typename _Tp> + using __piecewise_distributions_storage_t = double; +#elif defined(_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES) template<typename _Tp> using __piecewise_distributions_storage_t = _Tp; > > +#else > > + template<typename _Tp> > > + struct __piecewise_distributions_storage > > + { using type = _Tp; }; > > + > > + template<> > > + struct __piecewise_distributions_storage<float> > > + { using type = double; }; > > + > > +# ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT > > + template<> > > + struct __piecewise_distributions_storage<__ibm128> > > + { using type = double; }; > > + > > + template<> > > + struct __piecewise_distributions_storage<__ieee128> > > + { using type = double; }; > > +# elif __LDBL_MANT_DIG__ != __DBL_MANT_DIG__ > > + template<> > > + struct __piecewise_distributions_storage<long double> > > + { using type = double; }; > > +# endif > > + > > + template<typename _Tp> > > + using __piecewise_distributions_storage_t > > + = typename __piecewise_distributions_storage<_Tp>::type; > > +#endif // _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES > > + } > > + > > /** > > * @brief A piecewise_constant_distribution random number > distribution. > > * > > @@ -6407,6 +6441,9 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > static_assert(std::is_floating_point<_RealType>::value, > > "result_type must be a floating point type"); > > > > + using _StorageType > > + = __detail::__piecewise_distributions_storage_t<_RealType>; > > + > > public: > > /** The type of the range of the distribution. */ > > typedef _RealType result_type; > > @@ -6437,7 +6474,7 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > param_type(const param_type&) = default; > > param_type& operator=(const param_type&) = default; > > > > - std::vector<_RealType> > > + std::vector<result_type> > > intervals() const > > { > > if (_M_int.empty()) > > @@ -6450,9 +6487,34 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > return _M_int; > > } > > > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > std::vector<double> > > densities() const > > { return _M_den.empty() ? std::vector<double>(1, 1.0) : _M_den; } > > +#else > > + // _GLIBCXX_RESOLVE_LIB_DEFECTS > > + // 1439. Return from densities() functions? > > + [[__gnu__::__abi_tag__("__rt")]] > > + std::vector<result_type> > > + densities() const > > + { > > +#pragma GCC diagnostic push > > +#pragma GCC diagnostic ignored "-Wc++17-extensions" > > + if (_M_den.empty()) > > + return std::vector<_RealType>(1, _RealType(1)); > > + else if constexpr (is_same<_RealType, _StorageType>::value) > > + return _M_den; > > + else > > + { > > + std::vector<_RealType> __res; > > + __res.reserve(_M_den.size()); > > + for (_RealType __v : _M_den) > > + __res.push_back(__v); > > + return __res; > > + } > > +#pragma GCC diagnostic pop > > + } > > +#endif > > > > friend bool > > operator==(const param_type& __p1, const param_type& __p2) > > @@ -6472,8 +6534,8 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > _M_initialize2(const _RealType* __ints, _RealType __den); > > > > std::vector<_RealType> _M_int; > > - std::vector<double> _M_den; > > - std::vector<double> _M_cp; > > + std::vector<_StorageType> _M_den; > > + std::vector<_StorageType> _M_cp; > > > > template<typename _RealType1, typename _CharT, typename _Traits> > > friend std::basic_ostream<_CharT, _Traits>& > > @@ -6520,28 +6582,23 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > /** > > * @brief Returns a vector of the intervals. > > */ > > - std::vector<_RealType> > > + std::vector<result_type> > > intervals() const > > - { > > - if (_M_param._M_int.empty()) > > - { > > - std::vector<_RealType> __tmp(2); > > - __tmp[1] = _RealType(1); > > - return __tmp; > > - } > > - else > > - return _M_param._M_int; > > - } > > + { return _M_param.intervals(); } > > > > /** > > * @brief Returns a vector of the probability densities. > > */ > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > std::vector<double> > > densities() const > > - { > > - return _M_param._M_den.empty() > > - ? std::vector<double>(1, 1.0) : _M_param._M_den; > > - } > > + { return _M_param.densities(); } > > +#else > > + [[__gnu__::__always_inline__]] > > + std::vector<result_type> > > + densities() const > > + { return _M_param.densities(); } > > +#endif > > > > /** > > * @brief Returns the parameter set of the distribution. > > @@ -6695,6 +6752,9 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > static_assert(std::is_floating_point<_RealType>::value, > > "result_type must be a floating point type"); > > > > + using _StorageType > > + = __detail::__piecewise_distributions_storage_t<_RealType>; > > + > > public: > > /** The type of the range of the distribution. */ > > typedef _RealType result_type; > > @@ -6725,7 +6785,7 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > param_type(const param_type&) = default; > > param_type& operator=(const param_type&) = default; > > > > - std::vector<_RealType> > > + std::vector<result_type> > > intervals() const > > { > > if (_M_int.empty()) > > @@ -6738,9 +6798,34 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > return _M_int; > > } > > > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > std::vector<double> > > densities() const > > { return _M_den.empty() ? std::vector<double>(2, 1.0) : _M_den; } > > +#else > > + // _GLIBCXX_RESOLVE_LIB_DEFECTS > > + // 1439. Return from densities() functions? > > + [[__gnu__::__abi_tag__("__rt")]] > > + std::vector<result_type> > > + densities() const > > + { > > +#pragma GCC diagnostic push > > +#pragma GCC diagnostic ignored "-Wc++17-extensions" > > + if (_M_den.empty()) > > + return std::vector<_RealType>(2, _RealType(1)); > > + else if constexpr (is_same<_RealType, _StorageType>::value) > > + return _M_den; > > + else > > + { > > + std::vector<_RealType> __res; > > + __res.reserve(_M_den.size()); > > + for (_RealType __v : _M_den) > > + __res.push_back(__v); > > + return __res; > > + } > > +#pragma GCC diagnostic pop > > + } > > +#endif > > > > friend bool > > operator==(const param_type& __p1, const param_type& __p2) > > @@ -6760,9 +6845,9 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > _M_initialize2(const _RealType* __ints, const _RealType* __dens); > > > > std::vector<_RealType> _M_int; > > - std::vector<double> _M_den; > > - std::vector<double> _M_cp; > > - std::vector<double> _M_m; > > + std::vector<_StorageType> _M_den; > > + std::vector<_StorageType> _M_cp; > > + std::vector<_StorageType> _M_m; > > > > template<typename _RealType1, typename _CharT, typename _Traits> > > friend std::basic_ostream<_CharT, _Traits>& > > @@ -6809,29 +6894,24 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > > /** > > * @brief Return the intervals of the distribution. > > */ > > - std::vector<_RealType> > > + std::vector<result_type> > > intervals() const > > - { > > - if (_M_param._M_int.empty()) > > - { > > - std::vector<_RealType> __tmp(2); > > - __tmp[1] = _RealType(1); > > - return __tmp; > > - } > > - else > > - return _M_param._M_int; > > - } > > + { return _M_param.intervals(); } > > > > /** > > * @brief Return a vector of the probability densities of the > > * distribution. > > */ > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > std::vector<double> > > densities() const > > - { > > - return _M_param._M_den.empty() > > - ? std::vector<double>(2, 1.0) : _M_param._M_den; > > - } > > + { return _M_param.densities(); } > > +#else > > + [[__gnu__::__always_inline__]] > > + std::vector<result_type> > > + densities() const > > + { return _M_param.densities(); } > > +#endif > > > > /** > > * @brief Returns the parameter set of the distribution. > > diff --git a/libstdc++-v3/include/bits/random.tcc > b/libstdc++-v3/include/bits/random.tcc > > index e581f912764..6c88d68d3e4 100644 > > --- a/libstdc++-v3/include/bits/random.tcc > > +++ b/libstdc++-v3/include/bits/random.tcc > > @@ -3199,6 +3199,8 @@ namespace __detail > > piecewise_constant_distribution<_RealType>& __x) > > { > > using __ios_base = typename basic_istream<_CharT, > _Traits>::ios_base; > > + using _StorageType > > + = typename > piecewise_constant_distribution<_RealType>::_StorageType; > > > > const typename __ios_base::fmtflags __flags = __is.flags(); > > __is.flags(__ios_base::dec | __ios_base::skipws); > > @@ -3209,7 +3211,7 @@ namespace __detail > > std::vector<_RealType> __int_vec; > > if (__detail::__extract_params(__is, __int_vec, __n + 1)) > > { > > - std::vector<double> __den_vec; > > + std::vector<_StorageType> __den_vec; > > if (__detail::__extract_params(__is, __den_vec, __n)) > > { > > __x.param({ __int_vec.begin(), __int_vec.end(), > > @@ -3466,6 +3468,8 @@ namespace __detail > > piecewise_linear_distribution<_RealType>& __x) > > { > > using __ios_base = typename basic_istream<_CharT, > _Traits>::ios_base; > > + using _StorageType > > + = typename > piecewise_linear_distribution<_RealType>::_StorageType; > > > > const typename __ios_base::fmtflags __flags = __is.flags(); > > __is.flags(__ios_base::dec | __ios_base::skipws); > > @@ -3476,7 +3480,7 @@ namespace __detail > > vector<_RealType> __int_vec; > > if (__detail::__extract_params(__is, __int_vec, __n + 1)) > > { > > - vector<double> __den_vec; > > + vector<_StorageType> __den_vec; > > if (__detail::__extract_params(__is, __den_vec, __n + 1)) > > { > > __x.param({ __int_vec.begin(), __int_vec.end(), > > diff --git > a/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors.cc > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors.cc > > new file mode 100644 > > index 00000000000..219d1949040 > > --- /dev/null > > +++ > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors.cc > > @@ -0,0 +1,83 @@ > > +// { dg-do run { target c++11 } } > > +// { dg-require-cstdint "" } > > + > > +#include <random> > > +#include <testsuite_hooks.h> > > + > > +template<typename RealType> > > +void > > +test_exact() > > +{ > > + RealType x[6] = {0.0, 1.0, 2.0, 3.0, 4.0, 5.0}; > > + RealType wt[5] = {0.5, 1.0, 3.5, 2.5, 0.5}; > > + > > + std::piecewise_constant_distribution<RealType> > > + u(std::begin(x), std::end(x), wt); > > + > > + const std::vector<RealType>& interval = u.intervals(); > > + VERIFY( interval.size() == 6 ); > > + VERIFY( interval[0] == RealType(0.0) ); > > + VERIFY( interval[5] == RealType(5.0) ); > > + > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > + const std::vector<double>& density = u.densities(); > > +#else > > + const std::vector<RealType>& density = u.densities(); > > +#endif > > + > > + VERIFY( density.size() == 5 ); > > + VERIFY( density[0] == RealType(0.5 / 8.0) ); > > + VERIFY( density[1] == RealType(1.0 / 8.0) ); > > + VERIFY( density[2] == RealType(3.5 / 8.0) ); > > + VERIFY( density[3] == RealType(2.5 / 8.0) ); > > + VERIFY( density[4] == RealType(0.5 / 8.0) ); > > +} > > + > > +template<typename RealType> > > +void > > +test_precision_depended() > > +{ > > + constexpr bool preserved > > +#ifdef _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES > > + = true; > > +#else > > + = sizeof(RealType) <= sizeof(double); > > +#endif > > + > > + RealType x[3]{0.0, 0.5, 1.0}; > > + constexpr RealType step > > + = std::numeric_limits<RealType>::epsilon(); > > + RealType wt[2]{RealType(1) - step, RealType(1) + step}; > > + > > + std::piecewise_constant_distribution<RealType> > > + u(std::begin(x), std::end(x), wt); > > + > > + const std::vector<RealType>& interval = u.intervals(); > > + VERIFY( interval.size() == 3 ); > > + VERIFY( interval[0] == RealType(0.0) ); > > + VERIFY( interval[2] == RealType(1.0) ); > > + > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > + const std::vector<double>& density = u.densities(); > > +#else > > + const std::vector<RealType>& density = u.densities(); > > +#endif > > + > > + VERIFY( density.size() == 2 ); > > + VERIFY( density[0] == (preserved ? wt[0] : RealType(1)) ); > > + VERIFY( density[1] == (preserved ? wt[1] : RealType(1)) ); > > +} > > + > > +int main() > > +{ > > + using namespace __gnu_test; > > + test_exact<float>(); > > + test_exact<double>(); > > + test_exact<long double>(); > > + > > + test_precision_depended<float>(); > > + test_precision_depended<double>(); > > + test_precision_depended<long double>(); > > + > > + return 0; > > +} > > diff --git > a/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_exact.cc > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_exact.cc > > new file mode 100644 > > index 00000000000..469ed3fac46 > > --- /dev/null > > +++ > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_exact.cc > > @@ -0,0 +1,5 @@ > > +// { dg-options "-D_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES" } > > +// { dg-do run { target c++11 } } > > +// { dg-require-cstdint "" } > > +#include "accessors.cc" > > + > > diff --git > a/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_fallback.cc > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_fallback.cc > > new file mode 100644 > > index 00000000000..3e2fbf03430 > > --- /dev/null > > +++ > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_constant_distribution/operators/accessors_fallback.cc > > @@ -0,0 +1,5 @@ > > +// { dg-options "-D_GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS" } > > +// { dg-do run { target c++11 } } > > +// { dg-require-cstdint "" } > > +#include "accessors.cc" > > + > > diff --git > a/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors.cc > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors.cc > > new file mode 100644 > > index 00000000000..d3855ee0291 > > --- /dev/null > > +++ > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors.cc > > @@ -0,0 +1,85 @@ > > +// { dg-do run { target c++11 } } > > +// { dg-require-cstdint "" } > > + > > +#include <random> > > +#include <testsuite_hooks.h> > > + > > +template<typename RealType> > > +void > > +test_exact() > > +{ > > + RealType x[6] = {0.0, 1.0, 2.0, 3.0, 4.0, 5.0}; > > + RealType wt[6] = {0.0, 1.0, 1.0, 6.0, -1.0, 2.0}; > > + > > + std::piecewise_linear_distribution<RealType> > > + u(std::begin(x), std::end(x), wt); > > + > > + const std::vector<RealType>& interval = u.intervals(); > > + VERIFY( interval.size() == 6 ); > > + VERIFY( interval[0] == RealType(0.0) ); > > + VERIFY( interval[5] == RealType(5.0) ); > > + > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > + const std::vector<double>& density = u.densities(); > > +#else > > + const std::vector<RealType>& density = u.densities(); > > +#endif > > + > > + VERIFY( density.size() == 6 ); > > + VERIFY( density[0] == RealType(0.0 / 8.0) ); > > + VERIFY( density[1] == RealType(1.0 / 8.0) ); > > + VERIFY( density[2] == RealType(1.0 / 8.0) ); > > + VERIFY( density[3] == RealType(6.0 / 8.0) ); > > + VERIFY( density[4] == RealType(-1.0 / 8.0) ); > > + VERIFY( density[5] == RealType(2.0 / 8.0) ); > > +} > > + > > +template<typename RealType> > > +void > > +test_precision_depended() > > +{ > > + constexpr bool preserved > > +#ifdef _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES > > + = true; > > +#else > > + = sizeof(RealType) <= sizeof(double); > > +#endif > > + > > + RealType x[3]{0.0, 0.5, 1.0}; > > + constexpr RealType step > > + = std::numeric_limits<RealType>::epsilon() * 2; > > + RealType wt[3]{RealType(1) - step, RealType(1), RealType(1) + step}; > > + > > + std::piecewise_linear_distribution<RealType> > > + u(std::begin(x), std::end(x), wt); > > + > > + const std::vector<RealType>& interval = u.intervals(); > > + VERIFY( interval.size() == 3 ); > > + VERIFY( interval[0] == RealType(0.0) ); > > + VERIFY( interval[2] == RealType(1.0) ); > > + > > +#ifdef _GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS > > + const std::vector<double>& density = u.densities(); > > +#else > > + const std::vector<RealType>& density = u.densities(); > > +#endif > > + > > + VERIFY( density.size() == 3 ); > > + VERIFY( density[0] == (preserved ? wt[0] : RealType(1)) ); > > + VERIFY( density[1] == RealType(1) ); > > + VERIFY( density[2] == (preserved ? wt[2] : RealType(1)) ); > > +} > > + > > +int main() > > +{ > > + using namespace __gnu_test; > > + test_exact<float>(); > > + test_exact<double>(); > > + test_exact<long double>(); > > + > > + test_precision_depended<float>(); > > + test_precision_depended<double>(); > > + test_precision_depended<long double>(); > > + > > + return 0; > > +} > > diff --git > a/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_exact.cc > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_exact.cc > > new file mode 100644 > > index 00000000000..469ed3fac46 > > --- /dev/null > > +++ > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_exact.cc > > @@ -0,0 +1,5 @@ > > +// { dg-options "-D_GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES" } > > +// { dg-do run { target c++11 } } > > +// { dg-require-cstdint "" } > > +#include "accessors.cc" > > + > > diff --git > a/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_fallback.cc > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_fallback.cc > > new file mode 100644 > > index 00000000000..3e2fbf03430 > > --- /dev/null > > +++ > b/libstdc++-v3/testsuite/26_numerics/random/piecewise_linear_distribution/operators/accessors_fallback.cc > > @@ -0,0 +1,5 @@ > > +// { dg-options "-D_GLIBCXX_USE_OLD_PICEWISE_DISTRIBUTIONS" } > > +// { dg-do run { target c++11 } } > > +// { dg-require-cstdint "" } > > +#include "accessors.cc" > > + > > -- > > 2.54.0 > > > >
