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Faster RNG init

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paboyle
2017-02-07 01:33:23 -05:00
parent 2bf4688e83
commit 71ac2e7940
1 changed files with 97 additions and 62 deletions
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159
lib/lattice/Lattice_rng.h
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@@ -33,6 +33,7 @@ Author: paboyle <paboyle@ph.ed.ac.uk>
namespace Grid {
//http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-90Ar1.pdf ?
//////////////////////////////////////////////////////////////
// Allow the RNG state to be less dense than the fine grid
@@ -68,6 +69,7 @@ namespace Grid {
}
// Wrap seed_seq to give common interface with random_device
// Should rather wrap random_device and have a generate
class fixedSeed {
public:
@@ -75,20 +77,31 @@ namespace Grid {
std::seed_seq src;
fixedSeed(const std::vector<int> &seeds) : src(seeds.begin(),seeds.end()) {};
result_type operator () (void){
std::vector<result_type> list(1);
src.generate(list.begin(),list.end());
return list[0];
template<class int_type> fixedSeed(const std::vector<int_type> &seeds) : src(seeds.begin(),seeds.end()) {};
template< class RandomIt > void generate( RandomIt begin, RandomIt end ) {
src.generate(begin,end);
}
};
class deviceSeed {
public:
std::random_device rd;
typedef std::random_device::result_type result_type;
deviceSeed(void) : rd(){};
template< class RandomIt > void generate( RandomIt begin, RandomIt end ) {
for(RandomIt it=begin; it!=end;it++){
*it = rd();
}
}
};
// real scalars are one component
template<class scalar,class distribution,class generator> void fillScalar(scalar &s,distribution &dist,generator & gen)
{
@@ -122,7 +135,7 @@ namespace Grid {
std::vector<RngEngine> _generators;
std::vector<std::uniform_real_distribution<RealD>> _uniform;
std::vector<std::normal_distribution<RealD>> _gaussian;
std::vector<std::discrete_distribution<int32_t>> _bernoulli;
std::vector<std::discrete_distribution<int32_t>> _bernoulli;
void GetState(std::vector<RngStateType> & saved,int gen) {
saved.resize(RngStateCount);
@@ -150,13 +163,6 @@ namespace Grid {
// FIXME ... do we require lockstep draws of randoms
// from all nodes keeping seeds consistent.
// place a barrier/broadcast in the fill routine
template<class source> void Seed(source &src)
{
typename source::result_type init = src();
CartesianCommunicator::BroadcastWorld(0,(void *)&init,sizeof(init));
_generators[0] = RngEngine(init);
_seeded=1;
}
GridSerialRNG() : GridRNGbase() {
_generators.resize(1);
@@ -239,12 +245,17 @@ namespace Grid {
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template<class source> void Seed(source &src)
{
_generators[0] = RngEngine(src);
_seeded=1;
}
void SeedRandomDevice(void){
std::random_device rd;
Seed(rd);
deviceSeed src;
Seed(src);
}
void SeedFixedIntegers(const std::vector<int> &seeds){
CartesianCommunicator::BroadcastWorld(0,(void *)&seeds[0],sizeof(int)*seeds.size());
fixedSeed src(seeds);
Seed(src);
}
@@ -273,46 +284,6 @@ namespace Grid {
}
// 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
// iii)seed generators on each y,z for x=0
// iv) seed generators on each y,z,x
// made possible by physical indexing.
template<class source> void Seed(source &src)
{
std::vector<int> gcoor;
int gsites = _grid->_gsites;
typename source::result_type init = src();
RngEngine pseeder(init);
std::uniform_int_distribution<uint64_t> ui;
for(int 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);
const int num_rand_seed=16;
std::vector<int> site_seeds(num_rand_seed);
for(int i=0;i<site_seeds.size();i++){
site_seeds[i]= ui(pseeder);
}
_grid->Broadcast(0,(void *)&site_seeds[0],sizeof(int)*site_seeds.size());
if( rank == _grid->ThisRank() ){
fixedSeed ssrc(site_seeds);
typename source::result_type sinit = ssrc();
_generators[l_idx] = RngEngine(sinit);
}
}
_seeded=1;
}
//FIXME implement generic IO and create state save/restore
//void SaveState(const std::string<char> &file);
@@ -354,11 +325,75 @@ PARALLEL_FOR_LOOP
}
};
// 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
// iii)seed generators on each y,z for x=0
// iv) seed generators on each y,z,x
// made possible by physical indexing.
template<class source> void Seed(source &src)
{
typedef typename source::result_type seed_t;
std::uniform_int_distribution<seed_t> uid;
int numseed=4;
int gsites = _grid->_gsites;
std::vector<seed_t> site_init(numseed);
std::vector<int> gcoor;
// Master RngEngine
std::vector<seed_t> master_init(numseed); src.generate(master_init.begin(),master_init.end());
_grid->Broadcast(0,(void *)&master_init[0],sizeof(seed_t)*numseed);
fixedSeed master_seed(master_init);
RngEngine master_engine(master_seed);
// Per node RngEngine
std::vector<seed_t> node_init(numseed);
for(int r=0;r<_grid->ProcessorCount();r++) {
std::vector<seed_t> rank_init(numseed);
for(int i=0;i<numseed;i++) rank_init[i] = uid(master_engine);
std::cout << GridLogMessage << "SeedSeq for rank "<<r;
for(int i=0;i<numseed;i++) std::cout<<" "<<rank_init[i];
std::cout <<std::endl;
if ( r==_grid->ThisRank() ) {
for(int i=0;i<numseed;i++) node_init[i] = rank_init[i];
}
}
////////////////////////////////////////////////////
// Set up a seed_seq wrapper with these 8 words
// and draw for each site within node.
////////////////////////////////////////////////////
fixedSeed node_seed(node_init);
RngEngine node_engine(node_seed);
for(int gidx=0;gidx<gsites;gidx++){
int rank,o_idx,i_idx;
_grid->GlobalIndexToGlobalCoor(gidx,gcoor);
_grid->GlobalCoorToRankIndex(rank,o_idx,i_idx,gcoor);
if( rank == _grid->ThisRank() ){
int l_idx=generator_idx(o_idx,i_idx);
for(int i=0;i<numseed;i++) site_init[i] = uid(node_engine);
fixedSeed site_seed(site_init);
_generators[l_idx] = RngEngine(site_seed);
}
}
_seeded=1;
}
void SeedRandomDevice(void){
std::random_device rd;
Seed(rd);
deviceSeed src;
Seed(src);
}
void SeedFixedIntegers(const std::vector<int> &seeds){
CartesianCommunicator::BroadcastWorld(0,(void *)&seeds[0],sizeof(int)*seeds.size());
fixedSeed src(seeds);
Seed(src);
}