1 files changed, 132 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__random/exponential_distribution.h b/contrib/llvm-project/libcxx/include/__random/exponential_distribution.h
new file mode 100644
index 000000000000..e0e38841172f
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__random/exponential_distribution.h
@@ -0,0 +1,132 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_EXPONENTIAL_DISTRIBUTION_H
+#define _LIBCPP___RANDOM_EXPONENTIAL_DISTRIBUTION_H
+
+#include <__config>
+#include <__random/generate_canonical.h>
+#include <__random/is_valid.h>
+#include <__random/uniform_real_distribution.h>
+#include <cmath>
+#include <iosfwd>
+#include <limits>
+
+#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 _RealType = double>
+class _LIBCPP_TEMPLATE_VIS exponential_distribution {
+  static_assert(__libcpp_random_is_valid_realtype<_RealType>::value,
+                "RealType must be a supported floating-point type");
+
+public:
+  // types
+  typedef _RealType result_type;
+
+  class _LIBCPP_TEMPLATE_VIS param_type {
+    result_type __lambda_;
+
+  public:
+    typedef exponential_distribution distribution_type;
+
+    _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __lambda = 1) : __lambda_(__lambda) {}
+
+    _LIBCPP_HIDE_FROM_ABI result_type lambda() const { return __lambda_; }
+
+    friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
+      return __x.__lambda_ == __y.__lambda_;
+    }
+    friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
+  };
+
+private:
+  param_type __p_;
+
+public:
+  // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI exponential_distribution() : exponential_distribution(1) {}
+  _LIBCPP_HIDE_FROM_ABI explicit exponential_distribution(result_type __lambda) : __p_(param_type(__lambda)) {}
+#else
+  _LIBCPP_HIDE_FROM_ABI explicit exponential_distribution(result_type __lambda = 1) : __p_(param_type(__lambda)) {}
+#endif
+  _LIBCPP_HIDE_FROM_ABI explicit exponential_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 lambda() const { return __p_.lambda(); }
+
+  _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 numeric_limits<result_type>::infinity(); }
+
+  friend _LIBCPP_HIDE_FROM_ABI bool
+  operator==(const exponential_distribution& __x, const exponential_distribution& __y) {
+    return __x.__p_ == __y.__p_;
+  }
+  friend _LIBCPP_HIDE_FROM_ABI bool
+  operator!=(const exponential_distribution& __x, const exponential_distribution& __y) {
+    return !(__x == __y);
+  }
+};
+
+template <class _RealType>
+template <class _URNG>
+_RealType exponential_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p) {
+  static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
+  return -std::log(result_type(1) - std::generate_canonical<result_type, numeric_limits<result_type>::digits>(__g)) /
+         __p.lambda();
+}
+
+template <class _CharT, class _Traits, class _RealType>
+_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const exponential_distribution<_RealType>& __x) {
+  __save_flags<_CharT, _Traits> __lx(__os);
+  typedef basic_ostream<_CharT, _Traits> _OStream;
+  __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);
+  return __os << __x.lambda();
+}
+
+template <class _CharT, class _Traits, class _RealType>
+_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, exponential_distribution<_RealType>& __x) {
+  typedef exponential_distribution<_RealType> _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 __lambda;
+  __is >> __lambda;
+  if (!__is.fail())
+    __x.param(param_type(__lambda));
+  return __is;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANDOM_EXPONENTIAL_DISTRIBUTION_H