
.. _program_listing_file_library_include_rocrand_rocrand_mrg31k3p.h:

Program Listing for File rocrand_mrg31k3p.h
===========================================

|exhale_lsh| :ref:`Return to documentation for file <file_library_include_rocrand_rocrand_mrg31k3p.h>` (``library/include/rocrand/rocrand_mrg31k3p.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright (c) 2022 Advanced Micro Devices, Inc. All rights reserved.
   //
   // Permission is hereby granted, free of charge, to any person obtaining a copy
   // of this software and associated documentation files (the "Software"), to deal
   // in the Software without restriction, including without limitation the rights
   // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   // copies of the Software, and to permit persons to whom the Software is
   // furnished to do so, subject to the following conditions:
   //
   // The above copyright notice and this permission notice shall be included in
   // all copies or substantial portions of the Software.
   //
   // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
   // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   // THE SOFTWARE.
   
   #ifndef ROCRAND_MRG31K3P_H_
   #define ROCRAND_MRG31K3P_H_
   
   #ifndef FQUALIFIERS
       #define FQUALIFIERS __forceinline__ __device__
   #endif // FQUALIFIERS_
   
   #include "rocrand/rocrand_common.h"
   #include "rocrand/rocrand_mrg31k3p_precomputed.h"
   
   #define ROCRAND_MRG31K3P_M1 2147483647U // 2 ^ 31 - 1
   #define ROCRAND_MRG31K3P_M2 2147462579U // 2 ^ 31 - 21069
   #define ROCRAND_MRG31K3P_MASK12 511U // 2 ^ 9 - 1
   #define ROCRAND_MRG31K3P_MASK13 16777215U // 2 ^ 24 - 1
   #define ROCRAND_MRG31K3P_MASK21 65535U // 2 ^ 16 - 1
   #define ROCRAND_MRG31K3P_NORM_DOUBLE (4.656612875245796923e-10) // 1 / ROCRAND_MRG31K3P_M1
   #define ROCRAND_MRG31K3P_UINT32_NORM \
       (2.000000001396983862) // UINT32_MAX / (ROCRAND_MRG31K3P_M1 - 1)
   
   #define ROCRAND_MRG31K3P_DEFAULT_SEED 12345ULL
    // end of group rocranddevice
   namespace rocrand_device
   {
   
   class mrg31k3p_engine
   {
   public:
       struct mrg31k3p_state
       {
           unsigned int x1[3];
           unsigned int x2[3];
   
   #ifndef ROCRAND_DETAIL_MRG31K3P_BM_NOT_IN_STATE
           // The Box–Muller transform requires two inputs to convert uniformly
           // distributed real values [0; 1] to normally distributed real values
           // (with mean = 0, and stddev = 1). Often user wants only one
           // normally distributed number, to save performance and random
           // numbers the 2nd value is saved for future requests.
           unsigned int boxmuller_float_state; // is there a float in boxmuller_float
           unsigned int boxmuller_double_state; // is there a double in boxmuller_double
           float        boxmuller_float; // normally distributed float
           double       boxmuller_double; // normally distributed double
   #endif
       };
   
       FQUALIFIERS mrg31k3p_engine()
       {
           this->seed(ROCRAND_MRG31K3P_DEFAULT_SEED, 0, 0);
       }
   
       FQUALIFIERS mrg31k3p_engine(const unsigned long long seed,
                                   const unsigned long long subsequence,
                                   const unsigned long long offset)
       {
           this->seed(seed, subsequence, offset);
       }
   
       FQUALIFIERS void seed(unsigned long long       seed_value,
                             const unsigned long long subsequence,
                             const unsigned long long offset)
       {
           if(seed_value == 0)
           {
               seed_value = ROCRAND_MRG31K3P_DEFAULT_SEED;
           }
           unsigned int x = static_cast<unsigned int>(seed_value ^ 0x55555555U);
           unsigned int y = static_cast<unsigned int>((seed_value >> 32) ^ 0xAAAAAAAAU);
           m_state.x1[0]  = mod_mul_m1(x, seed_value);
           m_state.x1[1]  = mod_mul_m1(y, seed_value);
           m_state.x1[2]  = mod_mul_m1(x, seed_value);
           m_state.x2[0]  = mod_mul_m2(y, seed_value);
           m_state.x2[1]  = mod_mul_m2(x, seed_value);
           m_state.x2[2]  = mod_mul_m2(y, seed_value);
           this->restart(subsequence, offset);
       }
   
       FQUALIFIERS void discard(unsigned long long offset)
       {
           this->discard_impl(offset);
       }
   
       FQUALIFIERS void discard_subsequence(unsigned long long subsequence)
       {
           this->discard_subsequence_impl(subsequence);
       }
   
       FQUALIFIERS void discard_sequence(unsigned long long sequence)
       {
           this->discard_sequence_impl(sequence);
       }
   
       FQUALIFIERS void restart(const unsigned long long subsequence, const unsigned long long offset)
       {
   #ifndef ROCRAND_DETAIL_MRG31K3P_BM_NOT_IN_STATE
           m_state.boxmuller_float_state  = 0;
           m_state.boxmuller_double_state = 0;
   #endif
           this->discard_subsequence_impl(subsequence);
           this->discard_impl(offset);
       }
   
       FQUALIFIERS unsigned int operator()()
       {
           return this->next();
       }
   
       // Returned value is in range [1, ROCRAND_MRG31K3P_M1].
       FQUALIFIERS unsigned int next()
       {
           // First component
           unsigned int tmp
               = (((m_state.x1[1] & ROCRAND_MRG31K3P_MASK12) << 22) + (m_state.x1[1] >> 9))
                 + (((m_state.x1[2] & ROCRAND_MRG31K3P_MASK13) << 7) + (m_state.x1[2] >> 24));
           tmp -= (tmp >= ROCRAND_MRG31K3P_M1) ? ROCRAND_MRG31K3P_M1 : 0;
           tmp += m_state.x1[2];
           tmp -= (tmp >= ROCRAND_MRG31K3P_M1) ? ROCRAND_MRG31K3P_M1 : 0;
           m_state.x1[2] = m_state.x1[1];
           m_state.x1[1] = m_state.x1[0];
           m_state.x1[0] = tmp;
   
           // Second component
           tmp = (((m_state.x2[0] & ROCRAND_MRG31K3P_MASK21) << 15) + 21069 * (m_state.x2[0] >> 16));
           tmp -= (tmp >= ROCRAND_MRG31K3P_M2) ? ROCRAND_MRG31K3P_M2 : 0;
           tmp += ((m_state.x2[2] & ROCRAND_MRG31K3P_MASK21) << 15);
           tmp -= (tmp >= ROCRAND_MRG31K3P_M2) ? ROCRAND_MRG31K3P_M2 : 0;
           tmp += 21069 * (m_state.x2[2] >> 16);
           tmp -= (tmp >= ROCRAND_MRG31K3P_M2) ? ROCRAND_MRG31K3P_M2 : 0;
           tmp += m_state.x2[2];
           tmp -= (tmp >= ROCRAND_MRG31K3P_M2) ? ROCRAND_MRG31K3P_M2 : 0;
           m_state.x2[2] = m_state.x2[1];
           m_state.x2[1] = m_state.x2[0];
           m_state.x2[0] = tmp;
   
           // Combination
           return m_state.x1[0] - m_state.x2[0]
                  + (m_state.x1[0] <= m_state.x2[0] ? ROCRAND_MRG31K3P_M1 : 0);
       }
   
   protected:
       // Advances the internal state to skip \p offset numbers.
       FQUALIFIERS void discard_impl(unsigned long long offset)
       {
           discard_state(offset);
       }
   
       // Advances the internal state to skip \p subsequence subsequences.
       FQUALIFIERS void discard_subsequence_impl(unsigned long long subsequence)
       {
           int i = 0;
   
           while(subsequence > 0)
           {
               if(subsequence & 1)
               {
   #if defined(__HIP_DEVICE_COMPILE__)
                   mod_mat_vec_m1(d_mrg31k3p_A1P72 + i, m_state.x1);
                   mod_mat_vec_m2(d_mrg31k3p_A2P72 + i, m_state.x2);
   #else
                   mod_mat_vec_m1(h_mrg31k3p_A1P72 + i, m_state.x1);
                   mod_mat_vec_m2(h_mrg31k3p_A2P72 + i, m_state.x2);
   #endif
               }
               subsequence >>= 1;
               i += 9;
           }
       }
   
       // Advances the internal state to skip \p sequences.
       FQUALIFIERS void discard_sequence_impl(unsigned long long sequence)
       {
           int i = 0;
   
           while(sequence > 0)
           {
               if(sequence & 1)
               {
   #if defined(__HIP_DEVICE_COMPILE__)
                   mod_mat_vec_m1(d_mrg31k3p_A1P134 + i, m_state.x1);
                   mod_mat_vec_m2(d_mrg31k3p_A2P134 + i, m_state.x2);
   #else
                   mod_mat_vec_m1(h_mrg31k3p_A1P134 + i, m_state.x1);
                   mod_mat_vec_m2(h_mrg31k3p_A2P134 + i, m_state.x2);
   #endif
               }
               sequence >>= 1;
               i += 9;
           }
       }
   
       // Advances the internal state to skip \p offset numbers.
       FQUALIFIERS void discard_state(unsigned long long offset)
       {
           int i = 0;
   
           while(offset > 0)
           {
               if(offset & 1)
               {
   #if defined(__HIP_DEVICE_COMPILE__)
                   mod_mat_vec_m1(d_mrg31k3p_A1 + i, m_state.x1);
                   mod_mat_vec_m2(d_mrg31k3p_A2 + i, m_state.x2);
   #else
                   mod_mat_vec_m1(h_mrg31k3p_A1 + i, m_state.x1);
                   mod_mat_vec_m2(h_mrg31k3p_A2 + i, m_state.x2);
   #endif
               }
               offset >>= 1;
               i += 9;
           }
       }
   
       // Advances the internal state to the next state.
       FQUALIFIERS void discard_state()
       {
           discard_state(1);
       }
   
   private:
       FQUALIFIERS void mod_mat_vec_m1(const unsigned int* A, unsigned int* s)
       {
           unsigned long long x[3] = {s[0], s[1], s[2]};
   
           s[0] = mod_m1(mod_m1(A[0] * x[0]) + mod_m1(A[1] * x[1]) + mod_m1(A[2] * x[2]));
   
           s[1] = mod_m1(mod_m1(A[3] * x[0]) + mod_m1(A[4] * x[1]) + mod_m1(A[5] * x[2]));
   
           s[2] = mod_m1(mod_m1(A[6] * x[0]) + mod_m1(A[7] * x[1]) + mod_m1(A[8] * x[2]));
       }
   
       FQUALIFIERS void mod_mat_vec_m2(const unsigned int* A, unsigned int* s)
       {
           unsigned long long x[3] = {s[0], s[1], s[2]};
   
           s[0] = mod_m2(mod_m2(A[0] * x[0]) + mod_m2(A[1] * x[1]) + mod_m2(A[2] * x[2]));
   
           s[1] = mod_m2(mod_m2(A[3] * x[0]) + mod_m2(A[4] * x[1]) + mod_m2(A[5] * x[2]));
   
           s[2] = mod_m2(mod_m2(A[6] * x[0]) + mod_m2(A[7] * x[1]) + mod_m2(A[8] * x[2]));
       }
   
       FQUALIFIERS unsigned long long mod_mul_m1(unsigned int i, unsigned long long j)
       {
           return mod_m1(i * j);
       }
   
       FQUALIFIERS unsigned long long mod_m1(unsigned long long p)
       {
           return p % ROCRAND_MRG31K3P_M1;
       }
   
       FQUALIFIERS unsigned long long mod_mul_m2(unsigned int i, unsigned long long j)
       {
           return mod_m2(i * j);
       }
   
       FQUALIFIERS unsigned long long mod_m2(unsigned long long p)
       {
           return p % ROCRAND_MRG31K3P_M2;
       }
   
   protected:
       // State
       mrg31k3p_state m_state;
   
   #ifndef ROCRAND_DETAIL_MRG31K3P_BM_NOT_IN_STATE
       friend struct detail::engine_boxmuller_helper<mrg31k3p_engine>;
   #endif
   }; // mrg31k3p_engine class
   
   } // end namespace rocrand_device
   
   typedef rocrand_device::mrg31k3p_engine rocrand_state_mrg31k3p;
   
   FQUALIFIERS void rocrand_init(const unsigned long long seed,
                                 const unsigned long long subsequence,
                                 const unsigned long long offset,
                                 rocrand_state_mrg31k3p*  state)
   {
       *state = rocrand_state_mrg31k3p(seed, subsequence, offset);
   }
   
   FQUALIFIERS unsigned int rocrand(rocrand_state_mrg31k3p* state)
   {
       // next() in [1, ROCRAND_MRG31K3P_M1]
       return static_cast<unsigned int>((state->next() - 1) * ROCRAND_MRG31K3P_UINT32_NORM);
   }
   
   FQUALIFIERS void skipahead(unsigned long long offset, rocrand_state_mrg31k3p* state)
   {
       return state->discard(offset);
   }
   
   FQUALIFIERS void skipahead_subsequence(unsigned long long      subsequence,
                                          rocrand_state_mrg31k3p* state)
   {
       return state->discard_subsequence(subsequence);
   }
   
   FQUALIFIERS void skipahead_sequence(unsigned long long sequence, rocrand_state_mrg31k3p* state)
   {
       return state->discard_sequence(sequence);
   }
   
    // end of group rocranddevice
   #endif // ROCRAND_MRG31K3P_H_
