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Grid/Grid/algorithms/multigrid/Aggregates.h
2024-02-21 14:36:19 -05:00

384 lines
11 KiB
C++

/*************************************************************************************
Grid physics library, www.github.com/paboyle/Grid
Source file: ./lib/algorithms/Aggregates.h
Copyright (C) 2015
Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
Author: Peter Boyle <peterboyle@Peters-MacBook-Pro-2.local>
Author: paboyle <paboyle@ph.ed.ac.uk>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/* END LEGAL */
#pragma once
NAMESPACE_BEGIN(Grid);
inline RealD AggregatePowerLaw(RealD x)
{
// return std::pow(x,-4);
// return std::pow(x,-3);
return std::pow(x,-5);
}
template<class Fobj,class CComplex,int nbasis>
class Aggregation {
public:
constexpr int Nbasis(void) { return nbasis; };
typedef iVector<CComplex,nbasis > siteVector;
typedef Lattice<siteVector> CoarseVector;
typedef Lattice<iMatrix<CComplex,nbasis > > CoarseMatrix;
typedef Lattice< CComplex > CoarseScalar; // used for inner products on fine field
typedef Lattice<Fobj > FineField;
GridBase *CoarseGrid;
GridBase *FineGrid;
std::vector<Lattice<Fobj> > subspace;
int checkerboard;
int Checkerboard(void){return checkerboard;}
Aggregation(GridBase *_CoarseGrid,GridBase *_FineGrid,int _checkerboard) :
CoarseGrid(_CoarseGrid),
FineGrid(_FineGrid),
subspace(nbasis,_FineGrid),
checkerboard(_checkerboard)
{
};
void Orthogonalise(void){
CoarseScalar InnerProd(CoarseGrid);
// std::cout << GridLogMessage <<" Block Gramm-Schmidt pass 1"<<std::endl;
blockOrthogonalise(InnerProd,subspace);
}
void ProjectToSubspace(CoarseVector &CoarseVec,const FineField &FineVec){
blockProject(CoarseVec,FineVec,subspace);
}
void PromoteFromSubspace(const CoarseVector &CoarseVec,FineField &FineVec){
FineVec.Checkerboard() = subspace[0].Checkerboard();
blockPromote(CoarseVec,FineVec,subspace);
}
virtual void CreateSubspaceRandom(GridParallelRNG &RNG) {
int nn=nbasis;
RealD scale;
FineField noise(FineGrid);
for(int b=0;b<nn;b++){
subspace[b] = Zero();
gaussian(RNG,noise);
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
subspace[b] = noise;
}
}
virtual void CreateSubspace(GridParallelRNG &RNG,LinearOperatorBase<FineField> &hermop,int nn=nbasis)
{
RealD scale;
ConjugateGradient<FineField> CG(1.0e-2,100,false);
FineField noise(FineGrid);
FineField Mn(FineGrid);
for(int b=0;b<nn;b++){
subspace[b] = Zero();
gaussian(RNG,noise);
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
hermop.Op(noise,Mn); std::cout<<GridLogMessage << "noise ["<<b<<"] <n|MdagM|n> "<<norm2(Mn)<<std::endl;
for(int i=0;i<1;i++){
CG(hermop,noise,subspace[b]);
noise = subspace[b];
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
}
hermop.Op(noise,Mn); std::cout<<GridLogMessage << "filtered["<<b<<"] <f|MdagM|f> "<<norm2(Mn)<<std::endl;
subspace[b] = noise;
}
}
////////////////////////////////////////////////////////////////////////////////////////////////
// World of possibilities here. But have tried quite a lot of experiments (250+ jobs run on Summit)
// and this is the best I found
////////////////////////////////////////////////////////////////////////////////////////////////
virtual void CreateSubspaceChebyshev(GridParallelRNG &RNG,LinearOperatorBase<FineField> &hermop,
int nn,
double hi,
double lo,
int orderfilter,
int ordermin,
int orderstep,
double filterlo
) {
RealD scale;
FineField noise(FineGrid);
FineField Mn(FineGrid);
FineField tmp(FineGrid);
// New normalised noise
gaussian(RNG,noise);
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
std::cout << GridLogMessage<<" Chebyshev subspace pass-1 : ord "<<orderfilter<<" ["<<lo<<","<<hi<<"]"<<std::endl;
std::cout << GridLogMessage<<" Chebyshev subspace pass-2 : nbasis"<<nn<<" min "
<<ordermin<<" step "<<orderstep
<<" lo"<<filterlo<<std::endl;
// Initial matrix element
hermop.Op(noise,Mn); std::cout<<GridLogMessage << "noise <n|MdagM|n> "<<norm2(Mn)<<std::endl;
int b =0;
{
// Filter
Chebyshev<FineField> Cheb(lo,hi,orderfilter);
Cheb(hermop,noise,Mn);
// normalise
scale = std::pow(norm2(Mn),-0.5); Mn=Mn*scale;
subspace[b] = Mn;
hermop.Op(Mn,tmp);
std::cout<<GridLogMessage << "filt ["<<b<<"] <n|MdagM|n> "<<norm2(tmp)<<std::endl;
b++;
}
// Generate a full sequence of Chebyshevs
{
lo=filterlo;
noise=Mn;
FineField T0(FineGrid); T0 = noise;
FineField T1(FineGrid);
FineField T2(FineGrid);
FineField y(FineGrid);
FineField *Tnm = &T0;
FineField *Tn = &T1;
FineField *Tnp = &T2;
// Tn=T1 = (xscale M + mscale)in
RealD xscale = 2.0/(hi-lo);
RealD mscale = -(hi+lo)/(hi-lo);
hermop.HermOp(T0,y);
T1=y*xscale+noise*mscale;
for(int n=2;n<=ordermin+orderstep*(nn-2);n++){
hermop.HermOp(*Tn,y);
autoView( y_v , y, AcceleratorWrite);
autoView( Tn_v , (*Tn), AcceleratorWrite);
autoView( Tnp_v , (*Tnp), AcceleratorWrite);
autoView( Tnm_v , (*Tnm), AcceleratorWrite);
const int Nsimd = CComplex::Nsimd();
accelerator_for(ss, FineGrid->oSites(), Nsimd, {
coalescedWrite(y_v[ss],xscale*y_v(ss)+mscale*Tn_v(ss));
coalescedWrite(Tnp_v[ss],2.0*y_v(ss)-Tnm_v(ss));
});
// Possible more fine grained control is needed than a linear sweep,
// but huge productivity gain if this is simple algorithm and not a tunable
int m =1;
if ( n>=ordermin ) m=n-ordermin;
if ( (m%orderstep)==0 ) {
Mn=*Tnp;
scale = std::pow(norm2(Mn),-0.5); Mn=Mn*scale;
subspace[b] = Mn;
hermop.Op(Mn,tmp);
std::cout<<GridLogMessage << n<<" filt ["<<b<<"] <n|MdagM|n> "<<norm2(tmp)<<std::endl;
b++;
}
// Cycle pointers to avoid copies
FineField *swizzle = Tnm;
Tnm =Tn;
Tn =Tnp;
Tnp =swizzle;
}
}
assert(b==nn);
}
virtual void CreateSubspaceChebyshev(GridParallelRNG &RNG,LinearOperatorBase<FineField> &hermop,
int nn,
double hi,
double lo,
int orderfilter
) {
RealD scale;
FineField noise(FineGrid);
FineField Mn(FineGrid);
FineField tmp(FineGrid);
// New normalised noise
std::cout << GridLogMessage<<" Chebyshev subspace pure noise : ord "<<orderfilter<<" ["<<lo<<","<<hi<<"]"<<std::endl;
std::cout << GridLogMessage<<" Chebyshev subspace pure noise : nbasis "<<nn<<std::endl;
for(int b =0;b<nbasis;b++)
{
gaussian(RNG,noise);
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
// Initial matrix element
hermop.Op(noise,Mn);
if(b==0) std::cout<<GridLogMessage << "noise <n|MdagM|n> "<<norm2(Mn)<<std::endl;
// Filter
Chebyshev<FineField> Cheb(lo,hi,orderfilter);
Cheb(hermop,noise,Mn);
scale = std::pow(norm2(Mn),-0.5); Mn=Mn*scale;
// Refine
Chebyshev<FineField> PowerLaw(lo,hi,1000,AggregatePowerLaw);
noise = Mn;
PowerLaw(hermop,noise,Mn);
scale = std::pow(norm2(Mn),-0.5); Mn=Mn*scale;
// normalise
subspace[b] = Mn;
hermop.Op(Mn,tmp);
std::cout<<GridLogMessage << "filt ["<<b<<"] <n|MdagM|n> "<<norm2(tmp)<<std::endl;
}
}
virtual void CreateSubspaceChebyshevPowerLaw(GridParallelRNG &RNG,LinearOperatorBase<FineField> &hermop,
int nn,
double hi,
int orderfilter
) {
RealD scale;
FineField noise(FineGrid);
FineField Mn(FineGrid);
FineField tmp(FineGrid);
// New normalised noise
std::cout << GridLogMessage<<" Chebyshev subspace pure noise : ord "<<orderfilter<<" [0,"<<hi<<"]"<<std::endl;
std::cout << GridLogMessage<<" Chebyshev subspace pure noise : nbasis "<<nn<<std::endl;
for(int b =0;b<nbasis;b++)
{
gaussian(RNG,noise);
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
// Initial matrix element
hermop.Op(noise,Mn);
if(b==0) std::cout<<GridLogMessage << "noise <n|MdagM|n> "<<norm2(Mn)<<std::endl;
// Filter
Chebyshev<FineField> Cheb(0.0,hi,orderfilter,AggregatePowerLaw);
Cheb(hermop,noise,Mn);
// normalise
scale = std::pow(norm2(Mn),-0.5); Mn=Mn*scale;
subspace[b] = Mn;
hermop.Op(Mn,tmp);
std::cout<<GridLogMessage << "filt ["<<b<<"] <n|MdagM|n> "<<norm2(tmp)<<std::endl;
}
}
virtual void CreateSubspaceMultishift(GridParallelRNG &RNG,LinearOperatorBase<FineField> &hermop,
double Lo,double tol,int maxit)
{
RealD scale;
FineField noise(FineGrid);
FineField Mn(FineGrid);
FineField tmp(FineGrid);
// New normalised noise
std::cout << GridLogMessage<<" Multishift subspace : Lo "<<Lo<<std::endl;
// Filter
// [ 1/6(x+Lo) - 1/2(x+2Lo) + 1/2(x+3Lo) -1/6(x+4Lo) = Lo^3 /[ (x+1Lo)(x+2Lo)(x+3Lo)(x+4Lo) ]
//
// 1/(x+Lo) - 1/(x+2 Lo)
double epsilon = Lo/3;
std::vector<RealD> alpha({1.0/6.0,-1.0/2.0,1.0/2.0,-1.0/6.0});
std::vector<RealD> shifts({Lo,Lo+epsilon,Lo+2*epsilon,Lo+3*epsilon});
std::vector<RealD> tols({tol,tol,tol,tol});
std::cout << "sizes "<<alpha.size()<<" "<<shifts.size()<<" "<<tols.size()<<std::endl;
MultiShiftFunction msf(4,0.0,95.0);
std::cout << "msf constructed "<<std::endl;
msf.poles=shifts;
msf.residues=alpha;
msf.tolerances=tols;
msf.norm=0.0;
msf.order=alpha.size();
ConjugateGradientMultiShift<FineField> MSCG(maxit,msf);
for(int b =0;b<nbasis;b++)
{
gaussian(RNG,noise);
scale = std::pow(norm2(noise),-0.5);
noise=noise*scale;
// Initial matrix element
hermop.Op(noise,Mn);
if(b==0) std::cout<<GridLogMessage << "noise <n|MdagM|n> "<<norm2(Mn)<<std::endl;
MSCG(hermop,noise,Mn);
scale = std::pow(norm2(Mn),-0.5); Mn=Mn*scale;
subspace[b] = Mn;
hermop.Op(Mn,tmp);
std::cout<<GridLogMessage << "filt ["<<b<<"] <n|MdagM|n> "<<norm2(tmp)<<std::endl;
}
}
virtual void RefineSubspace(LinearOperatorBase<FineField> &hermop,
double Lo,double tol,int maxit)
{
FineField tmp(FineGrid);
for(int b =0;b<nbasis;b++)
{
RealD MirsShift = Lo;
ConjugateGradient<FineField> CGsloppy(tol,maxit,false);
ShiftedHermOpLinearOperator<FineField> ShiftedFineHermOp(hermop,MirsShift);
CGsloppy(hermop,subspace[b],tmp);
subspace[b]=tmp;
}
}
};
NAMESPACE_END(Grid);