Basic.h

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#ifndef EIGENRAND_DISTS_BASIC_H
#define EIGENRAND_DISTS_BASIC_H
 
namespace Eigen
{
    namespace Rand
    {
        namespace constant
        {
            static constexpr double pi = 3.1415926535897932;
            static constexpr double e = 2.7182818284590452;
        }
 
        template<typename DerivedGen, typename Scalar>
        class GenBase
        {
        public:
            template<typename Derived, typename Urng>
            inline const CwiseNullaryOp<internal::scalar_rng_adaptor<DerivedGen&, Scalar, Urng>, const Derived>
                generate(Index rows, Index cols, Urng&& urng)
            {
                return {
                    rows, cols, { std::forward<Urng>(urng), static_cast<DerivedGen&>(*this) }
                };
            }
 
            template<typename Derived, typename Urng>
            inline const CwiseNullaryOp<internal::scalar_rng_adaptor<DerivedGen&, Scalar, Urng>, const Derived>
                generateLike(const Derived& o, Urng&& urng)
            {
                return {
                    o.rows(), o.cols(), { std::forward<Urng>(urng), static_cast<DerivedGen&>(*this) }
                };
            }
        };
 
        template<typename DerivedGen, typename _Scalar, Index Dim>
        class MvVecGenBase
        {
        public:
            Index dims() const { return static_cast<DerivedGen&>(*this).dims(); }
 
            template<typename Urng>
            inline Matrix<_Scalar, Dim, -1> generate(Urng&& urng, Index samples)
            {
                return static_cast<DerivedGen&>(*this).generatr(std::forward<Urng>(urng), samples);
            }
 
            template<typename Urng>
            inline Matrix<_Scalar, Dim, 1> generate(Urng&& urng)
            {
                return static_cast<DerivedGen&>(*this).generatr(std::forward<Urng>(urng));
            }
        };
 
        template<typename DerivedGen, typename _Scalar, Index Dim>
        class MvMatGenBase
        {
        public:
            Index dims() const { return static_cast<DerivedGen&>(*this).dims(); }
 
            template<typename Urng>
            inline Matrix<_Scalar, Dim, -1> generate(Urng&& urng, Index samples)
            {
                return static_cast<DerivedGen&>(*this).generate(std::forward<Urng>(urng), samples);
            }
 
            template<typename Urng>
            inline Matrix<_Scalar, Dim, Dim> generate(Urng&& urng)
            {
                return static_cast<DerivedGen&>(*this).generate(std::forward<Urng>(urng));
            }
        };
 
        template<Index _alignment=0>
        class CacheStore
        {
        protected:
            enum { max_size = sizeof(internal::find_best_packet<float, -1>::type) };
            int8_t raw_data[max_size + _alignment - 1] = { 0, };
            void* aligned_ptr;
 
        public:
            CacheStore()
            {
                aligned_ptr = (void*)((((size_t)raw_data + _alignment - 1) / _alignment) * _alignment);
            }
 
            CacheStore(const CacheStore& c)
            {
                std::copy(c.raw_data, c.raw_data + max_size, raw_data);
                aligned_ptr = (void*)((((size_t)raw_data + _alignment - 1) / _alignment) * _alignment);
            }
 
            CacheStore(CacheStore&& c)
            {
                std::copy(c.raw_data, c.raw_data + max_size, raw_data);
                aligned_ptr = (void*)((((size_t)raw_data + _alignment - 1) / _alignment) * _alignment);
            }
 
            template<typename Ty>
            Ty& get()
            {
                return *(Ty*)aligned_ptr;
            }
 
            template<typename Ty>
            const Ty& get() const
            {
                return *(const Ty*)aligned_ptr;
            }
        };
 
        template<>
        class CacheStore<0>
        {
        protected:
            enum { max_size = sizeof(internal::find_best_packet<float, -1>::type) };
            int8_t raw_data[max_size] = { 0, };
 
        public:
            CacheStore()
            {
            }
 
            CacheStore(const CacheStore& c)
            {
                std::copy(c.raw_data, c.raw_data + max_size, raw_data);
            }
 
            CacheStore(CacheStore&& c)
            {
                std::copy(c.raw_data, c.raw_data + max_size, raw_data);
            }
 
            template<typename Ty>
            Ty& get()
            {
                return *(Ty*)raw_data;
            }
 
            template<typename Ty>
            const Ty& get() const
            {
                return *(const Ty*)raw_data;
            }
        };
 
        using OptCacheStore = CacheStore<EIGEN_MAX_ALIGN_BYTES>;
 
        template<typename _Scalar>
        class RandbitsGen : public GenBase<RandbitsGen<_Scalar>, _Scalar>
        {
            static_assert(std::is_integral<_Scalar>::value, "randBits needs integral types.");
        
        public:
            using Scalar = _Scalar;
 
            template<typename Rng>
            EIGEN_STRONG_INLINE const _Scalar operator() (Rng&& rng)
            {
                using namespace Eigen::internal;
                return pfirst(std::forward<Rng>(rng)());
            }
 
            template<typename Packet, typename Rng>
            EIGEN_STRONG_INLINE const Packet packetOp(Rng&& rng)
            {
                using namespace Eigen::internal;
                using RUtils = RawbitsMaker<Packet, Rng>;
                return RUtils{}.rawbits(std::forward<Rng>(rng));
            }
        };
 
        template<typename _Scalar>
        class BalancedGen : public GenBase<BalancedGen<_Scalar>, _Scalar>
        {
            static_assert(std::is_floating_point<_Scalar>::value, "balanced needs floating point types.");
 
        public:
            using Scalar = _Scalar;
 
            template<typename Rng>
            EIGEN_STRONG_INLINE const _Scalar operator() (Rng&& rng)
            {
                using namespace Eigen::internal;
                return ((_Scalar)((int32_t)pfirst(std::forward<Rng>(rng)()) & 0x7FFFFFFF) / 0x7FFFFFFF) * 2 - 1;
            }
 
            template<typename Packet, typename Rng>
            EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Packet packetOp(Rng&& rng)
            {
                using namespace Eigen::internal;
                using RUtils = RandUtils<Packet, Rng>;
                return RUtils{}.balanced(std::forward<Rng>(rng));
            }
        };
 
        template<typename _Scalar>
        class UniformRealGen : public GenBase<UniformRealGen<_Scalar>, _Scalar>
        {
            static_assert(std::is_floating_point<_Scalar>::value, "uniformReal needs floating point types.");
 
        public:
            using Scalar = _Scalar;
 
            template<typename Rng>
            EIGEN_STRONG_INLINE const _Scalar operator() (Rng&& rng)
            {
                using namespace Eigen::internal;
                return bit_scalar<_Scalar>{}.to_ur(pfirst(std::forward<Rng>(rng)()));
            }
 
            template<typename Rng>
            EIGEN_STRONG_INLINE const _Scalar nzur_scalar(Rng&& rng)
            {
                using namespace Eigen::internal;
                return bit_scalar<_Scalar>{}.to_nzur(pfirst(std::forward<Rng>(rng)()));
            }
 
            template<typename Packet, typename Rng>
            EIGEN_STRONG_INLINE const Packet packetOp(Rng&& rng)
            {
                using namespace Eigen::internal;
                using RUtils = RandUtils<Packet, Rng>;
                return RUtils{}.uniform_real(std::forward<Rng>(rng));
            }
        };
 
 
        template<typename _Scalar>
        class BernoulliGen : public GenBase<BernoulliGen<_Scalar>, _Scalar>
        {
            uint32_t p;
        public:
            using Scalar = _Scalar;
 
            BernoulliGen(double _p = 0.5)
            {
                eigen_assert(0 <= _p && _p <= 1 );
                p = (uint32_t)(_p * 0x80000000);
            }
 
            BernoulliGen(const BernoulliGen&) = default;
            BernoulliGen(BernoulliGen&&) = default;
 
            BernoulliGen& operator=(const BernoulliGen&) = default;
            BernoulliGen& operator=(BernoulliGen&&) = default;
 
            template<typename Rng>
            EIGEN_STRONG_INLINE const _Scalar operator() (Rng&& rng)
            {
                using namespace Eigen::internal;
                return (((uint32_t)pfirst(std::forward<Rng>(rng)()) & 0x7FFFFFFF) < p) ? 1 : 0;
            }
 
            template<typename Packet, typename Rng>
            EIGEN_STRONG_INLINE const Packet packetOp(Rng&& rng)
            {
                using namespace Eigen::internal;
                using IPacket = decltype(reinterpret_to_int(std::declval<Packet>()));
                using RUtils = RawbitsMaker<IPacket, Rng>;
                auto one = pset1<Packet>(1);
                auto zero = pset1<Packet>(0);
                auto r = RUtils{}.rawbits(std::forward<Rng>(rng));
                r = pand(r, pset1<IPacket>(0x7FFFFFFF));
                return pblendv(pcmplt(r, pset1<IPacket>(p)), one, zero);
            }
        };
 
 
        template<typename Derived, typename Urng>
        using RandBitsType = CwiseNullaryOp<internal::scalar_rng_adaptor<RandbitsGen<typename Derived::Scalar>, typename Derived::Scalar, Urng, true>, const Derived>;
 
        template<typename Derived, typename Urng>
        inline const RandBitsType<Derived, Urng>
            randBits(Index rows, Index cols, Urng&& urng)
        {
            return {
                rows, cols, { std::forward<Urng>(urng) }
            };
        }
 
        template<typename Derived, typename Urng>
        inline const RandBitsType<Derived, Urng>
            randBitsLike(Derived& o, Urng&& urng)
        {
            return {
                o.rows(), o.cols(), { std::forward<Urng>(urng) }
            };
        }
 
        template<typename Derived, typename Urng>
        using BalancedType = CwiseNullaryOp<internal::scalar_rng_adaptor<BalancedGen<typename Derived::Scalar>, typename Derived::Scalar, Urng, true>, const Derived>;
 
        template<typename Derived, typename Urng>
        inline const BalancedType<Derived, Urng>
            balanced(Index rows, Index cols, Urng&& urng)
        {
            return {
                rows, cols, { std::forward<Urng>(urng) }
            };
        }
 
        template<typename Derived, typename Urng>
        inline const BalancedType<Derived, Urng>
            balancedLike(const Derived& o, Urng&& urng)
        {
            return {
                o.rows(), o.cols(), { std::forward<Urng>(urng) }
            };
        }
 
        template<typename Derived, typename Urng>
        using UniformRealType = CwiseNullaryOp<internal::scalar_rng_adaptor<UniformRealGen<typename Derived::Scalar>, typename Derived::Scalar, Urng, true>, const Derived>;
 
        template<typename Derived, typename Urng>
        inline const UniformRealType<Derived, Urng>
            uniformReal(Index rows, Index cols, Urng&& urng)
        {
            return {
                rows, cols, { std::forward<Urng>(urng) }
            };
        }
 
        template<typename Derived, typename Urng>
        inline const UniformRealType<Derived, Urng>
            uniformRealLike(Derived& o, Urng&& urng)
        {
            return {
                o.rows(), o.cols(), { std::forward<Urng>(urng) }
            };
        }
 
        template<typename Derived, typename Urng>
        using BernoulliType = CwiseNullaryOp<internal::scalar_rng_adaptor<BernoulliGen<typename Derived::Scalar>, typename Derived::Scalar, Urng, true>, const Derived>;
 
        template<typename Derived, typename Urng>
        inline const BernoulliType<Derived, Urng>
            bernoulli(Index rows, Index cols, Urng&& urng, double p = 0.5)
        {
            return {
                rows, cols, { std::forward<Urng>(urng), BernoulliGen<typename Derived::Scalar>{ p } }
            };
        }
 
        template<typename Derived, typename Urng>
        inline const BernoulliType<Derived, Urng>
            bernoulli(Derived& o, Urng&& urng, double p = 0.5)
        {
            return {
                o.rows(), o.cols(), { std::forward<Urng>(urng), BernoulliGen<typename Derived::Scalar>{ p } }
            };
        }
    }
}
 
#endif