On Tue, 14 Jul 2026 at 08:07, 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 > 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. > --- > changes in v2: > * reworked description of _GLIBCXX_USE_OLD_PIECEWISE_DISTRIBUTIONS, > including spelling of "behavior" and "GCC 17" > * add missing dot for _GLIBCXX_USE_RESULT_TYPE_FOR_PIECEWISE_DENSITIES > * use std::vector<_RealType>(_M_den.begin(), _M_den.end()) to conver > the densities > The std qualification for vector is prevalent in this file, so kept > it for consistency.
I think that's because most of the code in <random> originated in <tr1/random> and we qualified things from std within std::tr1. It's vestigial now, but consistency is good. We can clean it all up some time, but not in this patch. > > Testing on x86_64-linux. Retested *piecewise* test will all standards, > debug/-m32. OK for trunk? > > .../doc/html/manual/using_macros.html | 19 +++ > libstdc++-v3/doc/xml/manual/using.xml | 29 ++++ > libstdc++-v3/include/bits/random.h | 145 +++++++++++++----- > 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, 350 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..4febcdbd1de 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_PIECEWISE_DISTRIBUTIONS</code></span></dt><dd><p> > + Undefined by default. > + When defined, the behavior specializations of Please add "of" after behavior. OK for trunk with that tweak. > + <code class="code">piecewise_constant_distribution</code> and > + <code class="code">piecewise_linear_distribution</code> > + is restored to their 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..63f24f56bc2 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_PIECEWISE_DISTRIBUTIONS</code></term> > + <listitem> > + <para> > + Undefined by default. > + When defined, the behavior specializations of > + <code>piecewise_constant_distribution</code> and > + <code>piecewise_linear_distribution</code> > + is restored to their 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 fd7b8b4fb20..c219930cc29 100644 > --- a/libstdc++-v3/include/bits/random.h > +++ b/libstdc++-v3/include/bits/random.h > @@ -6409,6 +6409,43 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > { return !(__d1 == __d2); } > #endif > > + namespace __detail > + { > +#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. > * > @@ -6431,6 +6468,9 @@ _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; > @@ -6461,7 +6501,7 @@ _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()) > @@ -6474,9 +6514,28 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > return _M_int; > } > > +#ifdef _GLIBCXX_USE_OLD_PIECEWISE_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 > + return std::vector<_RealType>(_M_den.begin(), _M_den.end()); > +#pragma GCC diagnostic pop > + } > +#endif > > friend bool > operator==(const param_type& __p1, const param_type& __p2) > @@ -6496,8 +6555,8 @@ _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>& > @@ -6544,28 +6603,23 @@ _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_PIECEWISE_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. > @@ -6719,6 +6773,9 @@ _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; > @@ -6749,7 +6806,7 @@ _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()) > @@ -6762,9 +6819,28 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2) > return _M_int; > } > > +#ifdef _GLIBCXX_USE_OLD_PIECEWISE_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 > + return std::vector<_RealType>(_M_den.begin(), _M_den.end()); > +#pragma GCC diagnostic pop > + } > +#endif > > friend bool > operator==(const param_type& __p1, const param_type& __p2) > @@ -6784,9 +6860,9 @@ _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>& > @@ -6833,29 +6909,24 @@ _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_PIECEWISE_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 a8fab79961d..12c891fbbaf 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..db4193847e3 > --- /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_PIECEWISE_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_PIECEWISE_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..1f7269a879c > --- /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_PIECEWISE_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..0a13e0fd9e2 > --- /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_PIECEWISE_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_PIECEWISE_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..1f7269a879c > --- /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_PIECEWISE_DISTRIBUTIONS" } > +// { dg-do run { target c++11 } } > +// { dg-require-cstdint "" } > +#include "accessors.cc" > + > -- > 2.54.0 >
