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use sha256 based splittable rng

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This commit is contained in:
Luchang Jin
2016-08-25 02:51:32 -04:00
parent 811ca45473
commit 71eaa7c79e
4 changed files with 798 additions and 1 deletions
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43
lib/lattice/Lattice_rng.h
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@ -31,6 +31,14 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
#include <random>
// Have not enable RNG_SPRNG_SHA256 by default yet.
// Uncomment the following line to see the effect of the new RNG.
// #define RNG_SPRNG_SHA256
#ifdef RNG_SPRNG_SHA256
#include "rng/sprng-sha256.h"
#endif
namespace Grid {
@ -110,7 +118,11 @@ namespace Grid {
int _seeded;
// One generator per site.
// Uniform and Gaussian distributions from these generators.
#ifdef RNG_RANLUX
#ifdef RNG_SPRNG_SHA256
typedef uint64_t RngStateType;
typedef SprngSha256 RngEngine;
static const int RngStateCount = 16;
#elif defined RNG_RANLUX
typedef uint64_t RngStateType;
typedef std::ranlux48 RngEngine;
static const int RngStateCount = 15;
@ -273,6 +285,34 @@ namespace Grid {
}
#ifdef RNG_SPRNG_SHA256
template<class source> void Seed(source &src)
{
std::vector<int> gcoor;
long gsites = _grid->_gsites;
RngState rs;
for (int i = 0; i < 8; ++i) {
splitRngState(rs, rs, src());
}
for(long gidx=0;gidx<gsites;gidx++){
int rank,o_idx,i_idx;
_grid->GlobalIndexToGlobalCoor(gidx,gcoor);
_grid->GlobalCoorToRankIndex(rank,o_idx,i_idx,gcoor);
int l_idx=generator_idx(o_idx,i_idx);
if( rank == _grid->ThisRank() ){
splitRngState(_generators[l_idx].rs, rs, gidx);
}
}
_seeded=1;
}
#else
// This loop could be made faster to avoid the Ahmdahl by
// i) seed generators on each timeslice, for x=y=z=0;
// ii) seed generators on each z for x=y=0
@ -312,6 +352,7 @@ namespace Grid {
}
_seeded=1;
}
#endif
//FIXME implement generic IO and create state save/restore
//void SaveState(const std::string<char> &file);