added random distribution adapters

include/distributions.h

@@ -0,0 +1,171 @@
+/*****************************************************************************
+ *
+ * AM numeric facilities
+ *
+ * released under MIT license
+ *
+ * 2008-2017 André Müller
+ *
+ *****************************************************************************/
+
+#ifndef AMLIB_NUMERIC_DISTRIBUTIONS_H_
+#define AMLIB_NUMERIC_DISTRIBUTIONS_H_
+
+
+#include <random>
+#include <functional>
+
+#include "param.h"
+#include "traits.h"
+
+
+namespace am {
+namespace num {
+
+/*****************************************************************************
+ *
+ *
+ *
+ *****************************************************************************/
+namespace detail {
+
+template<class NumT, bool isInt = is_integral<NumT>::value>
+struct uniform_number_distribution_helper
+{
+    using type = std::uniform_real_distribution<NumT>;
+};
+
+template<class NumT>
+struct uniform_number_distribution_helper<NumT,true>
+{
+    using type = std::uniform_int_distribution<NumT>;
+};
+
+
+}  // namespace detail
+
+
+
+//-------------------------------------------------------------------
+template<class NumT>
+using uniform_number_distribution = typename
+    detail::uniform_number_distribution_helper<NumT>::type;
+
+
+
+
+
+
+
+
+/*****************************************************************************
+ *
+ *
+ *
+ *
+ *
+ *****************************************************************************/
+template<class Result, class ValueDistribution>
+class distribution_adapter
+{
+    using component_type = numeric_t<Result>;
+
+public:
+    //---------------------------------------------------------------
+    using result_type = Result;
+    using param_type = param_t<ValueDistribution>;
+
+
+    //---------------------------------------------------------------
+    distribution_adapter() = default;
+
+    //-----------------------------------------------------
+    explicit
+    distribution_adapter(const param_type& p) :
+        distr_{p}
+    {}
+    //-----------------------------------------------------
+    template<class... Args>
+    explicit
+    distribution_adapter(Args&&... args) :
+        distr_{std::forward<Args>(args)...}
+    {}
+
+
+    //---------------------------------------------------------------
+    void
+    reset() {
+        distr_.reset();
+    }
+
+
+    //---------------------------------------------------------------
+    void
+    param(const param_type& par)    {
+        distr_.param(par);
+    }
+    //-----------------------------------------------------
+    auto
+    param() const -> decltype(std::declval<const ValueDistribution&>().param()) {
+        return distr_.param();
+    }
+
+    //-----------------------------------------------------
+    auto
+    min() const -> decltype(std::declval<const ValueDistribution&>().min()) {
+        return distr_.min();
+    }
+    //-----------------------------------------------------
+    auto
+    max() const -> decltype(std::declval<const ValueDistribution&>().max()) {
+        return distr_.max();
+    }
+
+    //---------------------------------------------------------------
+    template<class URBG>
+    result_type
+    operator () (URBG& urbg)
+    {
+        return operator()(urbg, distr_.param());
+    }
+    //-----------------------------------------------------
+    template<class URBG>
+    result_type
+    operator () (URBG& urbg, const param_type& par)
+    {
+        return result_type{distr_(urbg,par)};
+    }
+
+
+    //---------------------------------------------------------------
+    template<class Ostream>
+    friend Ostream&
+    operator<<(Ostream& os, const distribution_adapter& d) {
+        return (os << d.distr_);
+    }
+    //-----------------------------------------------------
+    template<class Istream>
+    friend Istream&
+    operator>>(Istream& is, distribution_adapter& d) {
+        return (is >> d.distr_);
+    }
+
+
+private:
+    ValueDistribution distr_;
+};
+
+
+
+//-------------------------------------------------------------------
+template<class Result>
+using uniform_distribution_adapter =
+    distribution_adapter<Result, uniform_number_distribution<numeric_t<Result>> >;
+
+
+
+}  // namespace num
+
+}  // namespace am
+
+#endif // AMLIB_GEOMETRY_CREATION_POINTS_H_