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https://github.com/paboyle/Grid.git
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281 lines
7.2 KiB
C++
281 lines
7.2 KiB
C++
//--------------------------------------------------------------------
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/*! @file Integrator_base.h
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* @brief Declaration of classes for the abstract Molecular Dynamics integrator
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*
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* @author Guido Cossu
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*/
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//--------------------------------------------------------------------
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#ifndef INTEGRATOR_INCLUDED
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#define INTEGRATOR_INCLUDED
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#include <memory>
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class Observer;
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/*! @brief Abstract base class for Molecular Dynamics management */
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namespace Grid{
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namespace QCD{
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typedef Action<LatticeLorentzColourMatrix>* ActPtr; // now force the same size as the rest of the code
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typedef std::vector<ActPtr> ActionLevel;
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typedef std::vector<ActionLevel> ActionSet;
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typedef std::vector<Observer*> ObserverList;
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struct IntegratorParameters{
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int Nexp;
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int MDsteps; // number of outer steps
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RealD trajL; // trajectory length
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RealD stepsize;
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IntegratorParameters(int Nexp_,
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int MDsteps_,
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RealD trajL_):
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Nexp(Nexp_),MDsteps(MDsteps_),trajL(trajL_),stepsize(trajL/MDsteps){};
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};
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namespace MDutils{
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void generate_momenta(LatticeLorentzColourMatrix&,GridParallelRNG&);
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void generate_momenta_su3(LatticeLorentzColourMatrix&,GridParallelRNG&);
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}
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template< class IntegratorPolicy >
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class Integrator{
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private:
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IntegratorParameters Params;
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const ActionSet as;
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const std::vector<int> Nrel; //relative step size per level
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std::unique_ptr<LatticeLorentzColourMatrix> P;
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GridParallelRNG pRNG;
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//ObserverList observers; // not yet
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IntegratorPolicy TheIntegrator;
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void register_observers();
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void notify_observers();
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void update_P(LatticeLorentzColourMatrix&U, int level,double ep){
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for(int a=0; a<as[level].size(); ++a){
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LatticeLorentzColourMatrix force(U._grid);
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as[level].at(a)->deriv(U,force);
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*P -= force*ep;
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}
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}
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void update_U(LatticeLorentzColourMatrix&U, double ep){
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//rewrite exponential to deal automatically with the lorentz index?
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LatticeColourMatrix Umu(U._grid);
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LatticeColourMatrix Pmu(U._grid);
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for (int mu = 0; mu < Nd; mu++){
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Umu=peekLorentz(U, mu);
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Pmu=peekLorentz(*P, mu);
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Umu = expMat(Pmu, ep, Params.Nexp)*Umu;
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pokeLorentz(U, Umu, mu);
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}
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}
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friend void IntegratorPolicy::step (LatticeLorentzColourMatrix& U,
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int level, std::vector<int>& clock,
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Integrator<IntegratorPolicy>* Integ);
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public:
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Integrator(GridBase* grid, IntegratorParameters Par,
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ActionSet& Aset, std::vector<int> Nrel_):
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Params(Par),as(Aset),Nrel(Nrel_),P(new LatticeLorentzColourMatrix(grid)),pRNG(grid){
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assert(as.size() == Nrel.size());
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pRNG.SeedRandomDevice();
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};
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~Integrator(){}
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//Initialization of momenta and actions
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void init(LatticeLorentzColourMatrix& U){
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std::cout<< "Integrator init\n";
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MDutils::generate_momenta(*P,pRNG);
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for(int level=0; level< as.size(); ++level){
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for(int actionID=0; actionID<as.at(level).size(); ++actionID){
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as[level].at(actionID)->init(U, pRNG);
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}
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}
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}
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// Calculate action
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RealD S(LatticeLorentzColourMatrix& U){
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LatticeComplex Hloc(U._grid);
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Hloc = zero;
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// Momenta
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for (int mu=0; mu <Nd; mu++){
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LatticeColourMatrix Pmu = peekLorentz(*P, mu);
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Hloc -= trace(Pmu*Pmu);
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}
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Complex Hsum = sum(Hloc);
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RealD H = Hsum.real();
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std::cout << "H_p = "<< H << "\n";
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// Actions
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for(int level=0; level<as.size(); ++level)
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for(int actionID=0; actionID<as.at(level).size(); ++actionID)
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H += as[level].at(actionID)->S(U);
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return H;
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}
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void integrate(LatticeLorentzColourMatrix& U, int level){
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std::vector<int> clock;
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clock.resize(as.size(),0);
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for(int step=0; step< Params.MDsteps; ++step) // MD step
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TheIntegrator.step(U,0,clock, (this));
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}
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};
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class MinimumNorm2{
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const double lambda = 0.1931833275037836;
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public:
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void step (LatticeLorentzColourMatrix& U,
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int level, std::vector<int>& clock,
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Integrator<MinimumNorm2>* Integ){
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// level : current level
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// fl : final level
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// eps : current step size
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int fl = Integ->as.size() -1;
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double eps = Integ->Params.stepsize;
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for(int l=0; l<=level; ++l) eps/= 2.0*Integ->Nrel[l];
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int fin = Integ->Nrel[0];
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for(int l=1; l<=level; ++l) fin*= 2.0*Integ->Nrel[l];
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fin = 3*Integ->Params.MDsteps*fin -1;
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for(int e=0; e<Integ->Nrel[level]; ++e){
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if(clock[level] == 0){ // initial half step
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Integ->update_P(U,level,lambda*eps);
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++clock[level];
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< clock[level] <<std::endl;
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}
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if(level == fl){ // lowest level
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Integ->update_U(U,0.5*eps);
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"U "<< (clock[level]+1) <<std::endl;
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}else{ // recursive function call
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step(U,level+1,clock, Integ);
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}
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Integ->update_P(U,level,(1.0-2.0*lambda)*eps);
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++clock[level];
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< (clock[level]) <<std::endl;
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if(level == fl){ // lowest level
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Integ->update_U(U,0.5*eps);
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"U "<< (clock[level]+1) <<std::endl;
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}else{ // recursive function call
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step(U,level+1,clock, Integ);
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}
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if(clock[level] == fin){ // final half step
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Integ->update_P(U,level,lambda*eps);
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++clock[level];
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< clock[level] <<std::endl;
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}else{ // bulk step
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Integ->update_P(U,level,lambda*2.0*eps);
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clock[level]+=2;
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< clock[level] <<std::endl;
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}
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}
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}
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};
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class LeapFrog{
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public:
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void step (LatticeLorentzColourMatrix& U,
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int level, std::vector<int>& clock,
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Integrator<LeapFrog>* Integ){
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// fl : final level
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// eps : current step size
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int fl = Integ->as.size() -1;
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double eps = Integ->Params.stepsize;
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// Get current level step size
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for(int l=0; l<=level; ++l) eps/= Integ->Nrel[l];
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int fin = 1;
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for(int l=0; l<=level; ++l) fin*= Integ->Nrel[l];
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fin = 2*Integ->Params.MDsteps*fin - 1;
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for(int e=0; e<Integ->Nrel[level]; ++e){
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if(clock[level] == 0){ // initial half step
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Integ->update_P(U, level,eps/2.0);
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++clock[level];
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< 0.5*clock[level] <<std::endl;
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}
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if(level == fl){ // lowest level
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Integ->update_U(U, eps);
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"U "<< 0.5*(clock[level]+1) <<std::endl;
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}else{ // recursive function call
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step(U, level+1,clock, Integ);
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}
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if(clock[level] == fin){ // final half step
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Integ->update_P(U, level,eps/2.0);
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++clock[level];
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< 0.5*clock[level] <<std::endl;
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}else{ // bulk step
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Integ->update_P(U, level,eps);
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clock[level]+=2;
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for(int l=0; l<level;++l) std::cout<<" ";
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std::cout<<"P "<< 0.5*clock[level] <<std::endl;
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}
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}
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}
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};
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}
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}
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#endif//INTEGRATOR_INCLUDED
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