1 files changed, 198 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__random/binomial_distribution.h b/contrib/llvm-project/libcxx/include/__random/binomial_distribution.h
new file mode 100644
index 000000000000..e8774bb8d67e
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__random/binomial_distribution.h
@@ -0,0 +1,198 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANDOM_BINOMIAL_DISTRIBUTION_H
+#define _LIBCPP___RANDOM_BINOMIAL_DISTRIBUTION_H
+
+#include <__config>
+#include <__random/is_valid.h>
+#include <__random/uniform_real_distribution.h>
+#include <cmath>
+#include <iosfwd>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _IntType = int>
+class _LIBCPP_TEMPLATE_VIS binomial_distribution {
+  static_assert(__libcpp_random_is_valid_inttype<_IntType>::value, "IntType must be a supported integer type");
+
+public:
+  // types
+  typedef _IntType result_type;
+
+  class _LIBCPP_TEMPLATE_VIS param_type {
+    result_type __t_;
+    double __p_;
+    double __pr_;
+    double __odds_ratio_;
+    result_type __r0_;
+
+  public:
+    typedef binomial_distribution distribution_type;
+
+    _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __t = 1, double __p = 0.5);
+
+    _LIBCPP_HIDE_FROM_ABI result_type t() const { return __t_; }
+    _LIBCPP_HIDE_FROM_ABI double p() const { return __p_; }
+
+    friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
+      return __x.__t_ == __y.__t_ && __x.__p_ == __y.__p_;
+    }
+    friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
+
+    friend class binomial_distribution;
+  };
+
+private:
+  param_type __p_;
+
+public:
+  // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI binomial_distribution() : binomial_distribution(1) {}
+  _LIBCPP_HIDE_FROM_ABI explicit binomial_distribution(result_type __t, double __p = 0.5)
+      : __p_(param_type(__t, __p)) {}
+#else
+  _LIBCPP_HIDE_FROM_ABI explicit binomial_distribution(result_type __t = 1, double __p = 0.5)
+      : __p_(param_type(__t, __p)) {}
+#endif
+  _LIBCPP_HIDE_FROM_ABI explicit binomial_distribution(const param_type& __p) : __p_(__p) {}
+  _LIBCPP_HIDE_FROM_ABI void reset() {}
+
+  // generating functions
+  template <class _URNG>
+  _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
+    return (*this)(__g, __p_);
+  }
+  template <class _URNG>
+  _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);
+
+  // property functions
+  _LIBCPP_HIDE_FROM_ABI result_type t() const { return __p_.t(); }
+  _LIBCPP_HIDE_FROM_ABI double p() const { return __p_.p(); }
+
+  _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }
+  _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }
+
+  _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }
+  _LIBCPP_HIDE_FROM_ABI result_type max() const { return t(); }
+
+  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const binomial_distribution& __x, const binomial_distribution& __y) {
+    return __x.__p_ == __y.__p_;
+  }
+  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const binomial_distribution& __x, const binomial_distribution& __y) {
+    return !(__x == __y);
+  }
+};
+
+#ifndef _LIBCPP_MSVCRT_LIKE
+extern "C" double lgamma_r(double, int*);
+#endif
+
+inline _LIBCPP_HIDE_FROM_ABI double __libcpp_lgamma(double __d) {
+#if defined(_LIBCPP_MSVCRT_LIKE)
+  return lgamma(__d);
+#else
+  int __sign;
+  return lgamma_r(__d, &__sign);
+#endif
+}
+
+template <class _IntType>
+binomial_distribution<_IntType>::param_type::param_type(result_type __t, double __p) : __t_(__t), __p_(__p) {
+  if (0 < __p_ && __p_ < 1) {
+    __r0_ = static_cast<result_type>((__t_ + 1) * __p_);
+    __pr_ = std::exp(
+        std::__libcpp_lgamma(__t_ + 1.) - std::__libcpp_lgamma(__r0_ + 1.) - std::__libcpp_lgamma(__t_ - __r0_ + 1.) +
+        __r0_ * std::log(__p_) + (__t_ - __r0_) * std::log(1 - __p_));
+    __odds_ratio_ = __p_ / (1 - __p_);
+  }
+}
+
+// Reference: Kemp, C.D. (1986). `A modal method for generating binomial
+//           variables', Commun. Statist. - Theor. Meth. 15(3), 805-813.
+template <class _IntType>
+template <class _URNG>
+_IntType binomial_distribution<_IntType>::operator()(_URNG& __g, const param_type& __pr) {
+  static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
+  if (__pr.__t_ == 0 || __pr.__p_ == 0)
+    return 0;
+  if (__pr.__p_ == 1)
+    return __pr.__t_;
+  uniform_real_distribution<double> __gen;
+  double __u = __gen(__g) - __pr.__pr_;
+  if (__u < 0)
+    return __pr.__r0_;
+  double __pu      = __pr.__pr_;
+  double __pd      = __pu;
+  result_type __ru = __pr.__r0_;
+  result_type __rd = __ru;
+  while (true) {
+    bool __break = true;
+    if (__rd >= 1) {
+      __pd *= __rd / (__pr.__odds_ratio_ * (__pr.__t_ - __rd + 1));
+      __u -= __pd;
+      __break = false;
+      if (__u < 0)
+        return __rd - 1;
+    }
+    if (__rd != 0)
+      --__rd;
+    ++__ru;
+    if (__ru <= __pr.__t_) {
+      __pu *= (__pr.__t_ - __ru + 1) * __pr.__odds_ratio_ / __ru;
+      __u -= __pu;
+      __break = false;
+      if (__u < 0)
+        return __ru;
+    }
+    if (__break)
+      return 0;
+  }
+}
+
+template <class _CharT, class _Traits, class _IntType>
+_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const binomial_distribution<_IntType>& __x) {
+  __save_flags<_CharT, _Traits> __lx(__os);
+  typedef basic_ostream<_CharT, _Traits> _OStream;
+  __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);
+  _CharT __sp = __os.widen(' ');
+  __os.fill(__sp);
+  return __os << __x.t() << __sp << __x.p();
+}
+
+template <class _CharT, class _Traits, class _IntType>
+_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, binomial_distribution<_IntType>& __x) {
+  typedef binomial_distribution<_IntType> _Eng;
+  typedef typename _Eng::result_type result_type;
+  typedef typename _Eng::param_type param_type;
+  __save_flags<_CharT, _Traits> __lx(__is);
+  typedef basic_istream<_CharT, _Traits> _Istream;
+  __is.flags(_Istream::dec | _Istream::skipws);
+  result_type __t;
+  double __p;
+  __is >> __t >> __p;
+  if (!__is.fail())
+    __x.param(param_type(__t, __p));
+  return __is;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANDOM_BINOMIAL_DISTRIBUTION_H