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Grid/lib/lattice/Lattice_rng.h
Peter Boyle 4e085dd0ed Domain wall even-odd 2f HMC with wilson gauge and PV 2f ratio now running and giving small dH.
Azusa is working hard on the rectangle term and we'll hopefully start reproducing plaquettes
from RBC-UKQCD parameters soon !

My new laptop is pretty warm and is starting to groan ;)
2015-08-19 10:26:07 +01:00

318 lines
9.1 KiB
C++

#ifndef GRID_LATTICE_RNG_H
#define GRID_LATTICE_RNG_H
#include <random>
namespace Grid {
//////////////////////////////////////////////////////////////
// Allow the RNG state to be less dense than the fine grid
//////////////////////////////////////////////////////////////
inline int RNGfillable(GridBase *coarse,GridBase *fine)
{
int rngdims = coarse->_ndimension;
// trivially extended in higher dims, with locality guaranteeing RNG state is local to node
int lowerdims = fine->_ndimension - coarse->_ndimension;
assert(lowerdims >= 0);
for(int d=0;d<lowerdims;d++){
assert(fine->_simd_layout[d]==1);
assert(fine->_processors[d]==1);
}
// local and global volumes subdivide cleanly after SIMDization
int multiplicity=1;
for(int d=0;d<rngdims;d++){
int fd= d+lowerdims;
assert(coarse->_processors[d] == fine->_processors[fd]);
assert(coarse->_simd_layout[d] == fine->_simd_layout[fd]);
assert((fine->_rdimensions[fd] / coarse->_rdimensions[d])* coarse->_rdimensions[d]==fine->_rdimensions[fd]);
multiplicity = multiplicity *fine->_rdimensions[fd] / coarse->_rdimensions[d];
}
return multiplicity;
}
// Wrap seed_seq to give common interface with random_device
class fixedSeed {
public:
typedef std::seed_seq::result_type result_type;
std::seed_seq src;
fixedSeed(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];
}
};
// real scalars are one component
template<class scalar,class distribution,class generator> void fillScalar(scalar &s,distribution &dist,generator & gen)
{
s=dist(gen);
}
template<class distribution,class generator> void fillScalar(ComplexF &s,distribution &dist, generator &gen)
{
s=ComplexF(dist(gen),dist(gen));
}
template<class distribution,class generator> void fillScalar(ComplexD &s,distribution &dist,generator &gen)
{
s=ComplexD(dist(gen),dist(gen));
}
class GridRNGbase {
public:
GridRNGbase() : _uniform{0,1}, _gaussian(0.0,1.0) {};
int _seeded;
// One generator per site.
// Uniform and Gaussian distributions from these generators.
std::vector<std::ranlux48> _generators;
std::uniform_real_distribution<double> _uniform;
std::normal_distribution<double> _gaussian;
};
class GridSerialRNG : public GridRNGbase {
public:
// 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] = std::ranlux48(init);
_seeded=1;
}
GridSerialRNG() : GridRNGbase() {
_generators.resize(1);
_seeded=0;
}
template <class sobj,class distribution> inline void fill(sobj &l,distribution &dist){
typedef typename sobj::scalar_type scalar_type;
int words = sizeof(sobj)/sizeof(scalar_type);
scalar_type *buf = (scalar_type *) & l;
for(int idx=0;idx<words;idx++){
fillScalar(buf[idx],dist,_generators[0]);
}
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
};
template <class distribution> inline void fill(ComplexF &l,distribution &dist){
fillScalar(l,dist,_generators[0]);
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template <class distribution> inline void fill(ComplexD &l,distribution &dist){
fillScalar(l,dist,_generators[0]);
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template <class distribution> inline void fill(RealF &l,distribution &dist){
fillScalar(l,dist,_generators[0]);
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template <class distribution> inline void fill(RealD &l,distribution &dist){
fillScalar(l,dist,_generators[0]);
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
// vector fill
template <class distribution> inline void fill(vComplexF &l,distribution &dist){
RealF *pointer=(RealF *)&l;
for(int i=0;i<2*vComplexF::Nsimd();i++){
fillScalar(pointer[i],dist,_generators[0]);
}
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template <class distribution> inline void fill(vComplexD &l,distribution &dist){
RealD *pointer=(RealD *)&l;
for(int i=0;i<2*vComplexD::Nsimd();i++){
fillScalar(pointer[i],dist,_generators[0]);
}
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template <class distribution> inline void fill(vRealF &l,distribution &dist){
RealF *pointer=(RealF *)&l;
for(int i=0;i<vRealF::Nsimd();i++){
fillScalar(pointer[i],dist,_generators[0]);
}
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
template <class distribution> inline void fill(vRealD &l,distribution &dist){
RealD *pointer=(RealD *)&l;
for(int i=0;i<vRealD::Nsimd();i++){
fillScalar(pointer[i],dist,_generators[0]);
}
CartesianCommunicator::BroadcastWorld(0,(void *)&l,sizeof(l));
}
void SeedRandomDevice(void){
std::random_device rd;
Seed(rd);
}
void SeedFixedIntegers(std::vector<int> &seeds){
fixedSeed src(seeds);
Seed(src);
}
};
class GridParallelRNG : public GridRNGbase {
public:
// One generator per site.
std::vector<std::ranlux48> _generators;
// Uniform and Gaussian distributions from these generators.
std::uniform_real_distribution<double> _uniform;
std::normal_distribution<double> _gaussian;
GridBase *_grid;
int _vol;
int generator_idx(int os,int is){
return is*_grid->oSites()+os;
}
GridParallelRNG(GridBase *grid) : GridRNGbase() {
_grid=grid;
_vol =_grid->iSites()*_grid->oSites();
_generators.resize(_vol);
_seeded=0;
}
// 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();
std::ranlux48 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);
std::vector<int> site_seeds(4);
for(int i=0;i<4;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] = std::ranlux48(sinit);
}
}
_seeded=1;
}
//FIXME implement generic IO and create state save/restore
//void SaveState(const std::string<char> &file);
//void LoadState(const std::string<char> &file);
template <class vobj,class distribution> inline void fill(Lattice<vobj> &l,distribution &dist){
typedef typename vobj::scalar_object scalar_object;
typedef typename vobj::scalar_type scalar_type;
typedef typename vobj::vector_type vector_type;
int multiplicity = RNGfillable(_grid,l._grid);
int Nsimd =_grid->Nsimd();
int osites=_grid->oSites();
int words=sizeof(scalar_object)/sizeof(scalar_type);
std::vector<scalar_object> buf(Nsimd);
PARALLEL_FOR_LOOP
for(int ss=0;ss<osites;ss++){
for(int m=0;m<multiplicity;m++) {// Draw from same generator multiplicity times
int sm=multiplicity*ss+m; // Maps the generator site to the fine site
for(int si=0;si<Nsimd;si++){
int gdx = generator_idx(ss,si); // index of generator state
scalar_type *pointer = (scalar_type *)&buf[si];
for(int idx=0;idx<words;idx++){
fillScalar(pointer[idx],dist,_generators[gdx]);
}
}
// merge into SIMD lanes
merge(l._odata[sm],buf);
}
}
};
void SeedRandomDevice(void){
std::random_device rd;
Seed(rd);
}
void SeedFixedIntegers(std::vector<int> &seeds){
fixedSeed src(seeds);
Seed(src);
}
};
template <class vobj> inline void random(GridParallelRNG &rng,Lattice<vobj> &l){
rng.fill(l,rng._uniform);
}
template <class vobj> inline void gaussian(GridParallelRNG &rng,Lattice<vobj> &l){
rng.fill(l,rng._gaussian);
}
template <class sobj> inline void random(GridSerialRNG &rng,sobj &l){
rng.fill(l,rng._uniform);
}
template <class sobj> inline void gaussian(GridSerialRNG &rng,sobj &l){
rng.fill(l,rng._gaussian);
}
}
#endif