
.. _program_listing_file_library_include_rocrand_rocrand_mrg32k3a.h:

Program Listing for File rocrand_mrg32k3a.h
===========================================

|exhale_lsh| :ref:`Return to documentation for file <file_library_include_rocrand_rocrand_mrg32k3a.h>` (``library/include/rocrand/rocrand_mrg32k3a.h``)

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

.. code-block:: cpp

   // Copyright (c) 2017-2022 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_MRG32K3A_H_
   #define ROCRAND_MRG32K3A_H_
   
   #ifndef FQUALIFIERS
   #define FQUALIFIERS __forceinline__ __device__
   #endif // FQUALIFIERS_
   
   #include "rocrand/rocrand_common.h"
   #include "rocrand/rocrand_mrg32k3a_precomputed.h"
   
   #define ROCRAND_MRG32K3A_POW32 4294967296
   #define ROCRAND_MRG32K3A_M1 4294967087
   #define ROCRAND_MRG32K3A_M1C 209
   #define ROCRAND_MRG32K3A_M2 4294944443
   #define ROCRAND_MRG32K3A_M2C 22853
   #define ROCRAND_MRG32K3A_A12 1403580
   #define ROCRAND_MRG32K3A_A13 (4294967087 -  810728)
   #define ROCRAND_MRG32K3A_A13N 810728
   #define ROCRAND_MRG32K3A_A21 527612
   #define ROCRAND_MRG32K3A_A23 (4294944443 - 1370589)
   #define ROCRAND_MRG32K3A_A23N 1370589
   #define ROCRAND_MRG32K3A_NORM_DOUBLE (2.3283065498378288e-10) // 1/ROCRAND_MRG32K3A_M1
   #define ROCRAND_MRG32K3A_UINT_NORM (1.000000048661607) // (ROCRAND_MRG32K3A_POW32 - 1)/(ROCRAND_MRG32K3A_M1 - 1)
   
    #define ROCRAND_MRG32K3A_DEFAULT_SEED 12345ULL
    // end of group rocranddevice
   namespace rocrand_device {
   
   class mrg32k3a_engine
   {
   public:
       struct mrg32k3a_state
       {
           unsigned int g1[3];
           unsigned int g2[3];
   
           #ifndef ROCRAND_DETAIL_MRG32K3A_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
       mrg32k3a_engine()
       {
           this->seed(ROCRAND_MRG32K3A_DEFAULT_SEED, 0, 0);
       }
   
       FQUALIFIERS
       mrg32k3a_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_MRG32K3A_DEFAULT_SEED;
           }
           unsigned int x = (unsigned int) seed_value ^ 0x55555555U;
           unsigned int y = (unsigned int) ((seed_value >> 32) ^ 0xAAAAAAAAU);
           m_state.g1[0] = mod_mul_m1(x, seed_value);
           m_state.g1[1] = mod_mul_m1(y, seed_value);
           m_state.g1[2] = mod_mul_m1(x, seed_value);
           m_state.g2[0] = mod_mul_m2(y, seed_value);
           m_state.g2[1] = mod_mul_m2(x, seed_value);
           m_state.g2[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_MRG32K3A_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_MRG32K3A_M1],
       // where ROCRAND_MRG32K3A_M1 < UINT_MAX
       FQUALIFIERS
       unsigned int next()
       {
           const unsigned int p1 = mod_m1(
               detail::mad_u64_u32(
                   ROCRAND_MRG32K3A_A12,
                   m_state.g1[1],
                   detail::mad_u64_u32(
                       ROCRAND_MRG32K3A_A13N,
                       (ROCRAND_MRG32K3A_M1 - m_state.g1[0]),
                       0
                   )
               )
           );
   
           m_state.g1[0] = m_state.g1[1]; m_state.g1[1] = m_state.g1[2];
           m_state.g1[2] = p1;
   
           const unsigned int p2 = mod_m2(
               detail::mad_u64_u32(
                   ROCRAND_MRG32K3A_A21,
                   m_state.g2[2],
                   detail::mad_u64_u32(
                       ROCRAND_MRG32K3A_A23N,
                       (ROCRAND_MRG32K3A_M2 - m_state.g2[0]),
                       0
                   )
               )
           );
   
           m_state.g2[0] = m_state.g2[1]; m_state.g2[1] = m_state.g2[2];
           m_state.g2[2] = p2;
   
           return (p1 - p2) + (p1 <= p2 ? ROCRAND_MRG32K3A_M1 : 0);
       }
   
   protected:
       // Advances the internal state to skip \p offset numbers.
       // DOES NOT CALCULATE NEW ULONGLONG
       FQUALIFIERS
       void discard_impl(unsigned long long offset)
       {
           discard_state(offset);
       }
   
       // DOES NOT CALCULATE NEW ULONGLONG
       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_A1P76 + i, m_state.g1);
                   mod_mat_vec_m2(d_A2P76 + i, m_state.g2);
                   #else
                   mod_mat_vec_m1(h_A1P76 + i, m_state.g1);
                   mod_mat_vec_m2(h_A2P76 + i, m_state.g2);
                   #endif
               }
               subsequence >>= 1;
               i += 9;
           }
       }
   
       // DOES NOT CALCULATE NEW ULONGLONG
       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_A1P127 + i, m_state.g1);
                   mod_mat_vec_m2(d_A2P127 + i, m_state.g2);
                   #else
                   mod_mat_vec_m1(h_A1P127 + i, m_state.g1);
                   mod_mat_vec_m2(h_A2P127 + i, m_state.g2);
                   #endif
               }
               sequence >>= 1;
               i += 9;
           }
       }
   
       // Advances the internal state by offset times.
       // DOES NOT CALCULATE NEW ULONGLONG
       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_A1 + i, m_state.g1);
                   mod_mat_vec_m2(d_A2 + i, m_state.g2);
                   #else
                   mod_mat_vec_m1(h_A1 + i, m_state.g1);
                   mod_mat_vec_m2(h_A2 + i, m_state.g2);
                   #endif
               }
               offset >>= 1;
               i += 9;
           }
       }
   
       // Advances the internal state to the next state
       // DOES NOT CALCULATE NEW ULONGLONG
       FQUALIFIERS
       void discard_state()
       {
           discard_state(1);
       }
   
   private:
       FQUALIFIERS
       void mod_mat_vec_m1(const unsigned long long * A,
                           unsigned int * s)
       {
           unsigned long long x[3];
   
           x[0] = mod_m1(mod_m1(A[0] * s[0])
                       + mod_m1(A[1] * s[1])
                       + mod_m1(A[2] * s[2]));
   
           x[1] = mod_m1(mod_m1(A[3] * s[0])
                       + mod_m1(A[4] * s[1])
                       + mod_m1(A[5] * s[2]));
   
           x[2] = mod_m1(mod_m1(A[6] * s[0])
                       + mod_m1(A[7] * s[1])
                       + mod_m1(A[8] * s[2]));
   
           s[0] = x[0];
           s[1] = x[1];
           s[2] = x[2];
       }
   
       FQUALIFIERS
       void mod_mat_vec_m2(const unsigned long long * A,
                           unsigned int * s)
       {
           unsigned long long x[3];
   
           x[0] = mod_m2(mod_m2(A[0] * s[0])
                       + mod_m2(A[1] * s[1])
                       + mod_m2(A[2] * s[2]));
   
           x[1] = mod_m2(mod_m2(A[3] * s[0])
                       + mod_m2(A[4] * s[1])
                       + mod_m2(A[5] * s[2]));
   
           x[2] = mod_m2(mod_m2(A[6] * s[0])
                       + mod_m2(A[7] * s[1])
                       + mod_m2(A[8] * s[2]));
   
           s[0] = x[0];
           s[1] = x[1];
           s[2] = x[2];
       }
   
       FQUALIFIERS
       unsigned long long mod_mul_m1(unsigned int i,
                                     unsigned long long j)
       {
           long long hi, lo, temp1, temp2;
   
           hi = i / 131072;
           lo = i - (hi * 131072);
           temp1 = mod_m1(hi * j) * 131072;
           temp2 = mod_m1(lo * j);
           lo = mod_m1(temp1 + temp2);
   
           if (lo < 0)
               lo += ROCRAND_MRG32K3A_M1;
           return lo;
       }
   
       FQUALIFIERS
       unsigned long long mod_m1(unsigned long long p)
       {
           p = detail::mad_u64_u32(ROCRAND_MRG32K3A_M1C, (p >> 32), p & (ROCRAND_MRG32K3A_POW32 - 1));
           if (p >= ROCRAND_MRG32K3A_M1)
               p -= ROCRAND_MRG32K3A_M1;
   
           return p;
       }
   
       FQUALIFIERS
       unsigned long long mod_mul_m2(unsigned int i,
                                     unsigned long long j)
       {
           long long hi, lo, temp1, temp2;
   
           hi = i / 131072;
           lo = i - (hi * 131072);
           temp1 = mod_m2(hi * j) * 131072;
           temp2 = mod_m2(lo * j);
           lo = mod_m2(temp1 + temp2);
   
           if (lo < 0)
               lo += ROCRAND_MRG32K3A_M2;
           return lo;
       }
   
       FQUALIFIERS
       unsigned long long mod_m2(unsigned long long p)
       {
           p = detail::mad_u64_u32(ROCRAND_MRG32K3A_M2C, (p >> 32), p & (ROCRAND_MRG32K3A_POW32 - 1));
           p = detail::mad_u64_u32(ROCRAND_MRG32K3A_M2C, (p >> 32), p & (ROCRAND_MRG32K3A_POW32 - 1));
           if (p >= ROCRAND_MRG32K3A_M2)
               p -= ROCRAND_MRG32K3A_M2;
   
           return p;
       }
   
   protected:
       // State
       mrg32k3a_state m_state;
   
       #ifndef ROCRAND_DETAIL_MRG32K3A_BM_NOT_IN_STATE
       friend struct detail::engine_boxmuller_helper<mrg32k3a_engine>;
       #endif
   
   }; // mrg32k3a_engine class
   
   } // end namespace rocrand_device
   
   typedef rocrand_device::mrg32k3a_engine rocrand_state_mrg32k3a;
   
   FQUALIFIERS
   void rocrand_init(const unsigned long long seed,
                     const unsigned long long subsequence,
                     const unsigned long long offset,
                     rocrand_state_mrg32k3a * state)
   {
       *state = rocrand_state_mrg32k3a(seed, subsequence, offset);
   }
   
   FQUALIFIERS
   unsigned int rocrand(rocrand_state_mrg32k3a * state)
   {
       // next() in [1, ROCRAND_MRG32K3A_M1]
       return static_cast<unsigned int>((state->next() - 1) * ROCRAND_MRG32K3A_UINT_NORM);
   }
   
   FQUALIFIERS
   void skipahead(unsigned long long offset, rocrand_state_mrg32k3a * state)
   {
       return state->discard(offset);
   }
   
   FQUALIFIERS
   void skipahead_subsequence(unsigned long long subsequence, rocrand_state_mrg32k3a * state)
   {
       return state->discard_subsequence(subsequence);
   }
   
   FQUALIFIERS
   void skipahead_sequence(unsigned long long sequence, rocrand_state_mrg32k3a * state)
   {
       return state->discard_sequence(sequence);
   }
   
   #endif // ROCRAND_MRG32K3A_H_
   
