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Commit 9d96216e authored by Joao Dos Santos Ferreira's avatar Joao Dos Santos Ferreira
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Delete auxiliar.h

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//
// My version of TEVOL, the args "Swipe"="left" or "right" defines the orientation.
//
#ifndef __ITENSOR_3TEBD_H
#define __ITENSOR_3TEBD_H
#include "itensor/all.h"
#include "itensor/mps/mpo.h"
#include "itensor/mps/TEvolObserver.h"
using namespace std;
using namespace itensor;
class BondGate3{
public:
enum Type { tReal, tImag};
BondGate3(SiteSet const& sites,int i1,int i2,int i3,Type type,Cplx tau,ITensor bondH,string which_swipe);
BondGate3(SiteSet const& sites,int i1,int i2,int i3,Type type,Real tau,ITensor bondH,string which_swipe);
int i1() const { return i1_; }
int i2() const { return i2_; }
int i3() const { return i3_; }
operator const ITensor&() const { return gate_; }
ITensor const&
gate() const { return gate_; }
Type
type() const { return type_; }
void
set_swipe(string tt) { swipe_=tt; }
string get_swipe() const {return swipe_;}
private:
Type type_;
int i1_,i2_,i3_; // The left, right indices of bond
ITensor gate_;
string swipe_; //
};
template <class Iterable>
Real
gateTEvolMixed(Iterable const& gatelist,Real ttotal,Real tstep,MPS & psi,Args args);
//
//
// Implementations
//
ITensor inline
operator*(BondGate3 const& G, ITensor T) { T *= G.gate(); return T; }
ITensor inline
operator*(ITensor T, BondGate3 const& G) { T *= G.gate(); return T; }
//Receives a three site tensor
inline BondGate3::
BondGate3(SiteSet const& sites,
int i1,
int i2,
int i3,
Type type,
Cplx tau,
ITensor bondH,
string which_swipe)
: type_(type)
{
swipe_=which_swipe;
vector<int> ax{i1,i2,i3};
std::sort(ax.begin(), ax.end());
i1_=ax[0];
i2_=ax[1];
i3_=ax[2];
if(!(type_ == tReal || type_ ==tImag))
{
Error("When providing bondH, type must be tReal or tImag");
}
bondH *= -tau;
ITensor unit = sites.op("Id",i1_)*sites.op("Id",i2_)*sites.op("Id",i3_);
if(type_ == tReal)
{
bondH *= Complex_i;
}
auto term = bondH;
bondH.replaceTags("1","2");
bondH.replaceTags("0","1");
// exp(x) = 1 + x + x^2/2! + x^3/3! ..
// = 1 + x * (1 + x/2 *(1 + x/3 * (...
// ~ ((x/3 + 1) * x/2 + 1) * x + 1
for(int ord = 100; ord >= 1; --ord)
{
term /= ord;
gate_ = unit + term;
term = gate_ * bondH;
term.replaceTags("2","1");
}
}
//Receives a three site tensor
inline BondGate3::
BondGate3(SiteSet const& sites,
int i1,
int i2,
int i3,
Type type,
Real tau,
ITensor bondH,
string which_swipe)
: type_(type)
{
swipe_=which_swipe;
vector<int> ax{i1,i2,i3};
std::sort(ax.begin(), ax.end());
i1_=ax[0];
i2_=ax[1];
i3_=ax[2];
if(!(type_ == tReal || type_ ==tImag))
{
Error("When providing bondH, type must be tReal or tImag");
}
bondH *= -tau;
ITensor unit = sites.op("Id",i1_)*sites.op("Id",i2_)*sites.op("Id",i3_);
if(type_ == tReal)
{
bondH *= Complex_i;
}
auto term = bondH;
bondH.replaceTags("1","2");
bondH.replaceTags("0","1");
// exp(x) = 1 + x + x^2/2! + x^3/3! ..
// = 1 + x * (1 + x/2 *(1 + x/3 * (...
// ~ ((x/3 + 1) * x/2 + 1) * x + 1
for(int ord = 100; ord >= 1; --ord)
{
term /= ord;
gate_ = unit + term;
term = gate_ * bondH;
term.replaceTags("2","1");
}
}
template <class Iterable>
Real
gateTEvolMixed(Iterable const& gatelist,Real ttotal,Real tstep,MPS & psi,Args args){
TEvolObserver obs(args);
const bool verbose = args.getBool("Verbose",false);
const bool do_normalize = args.getBool("Normalize",true);
const string which_swipe = args.getString("Swipe","error");
const int nt = int(ttotal/tstep+(1e-9*(ttotal/tstep)));
if(fabs(nt*tstep-ttotal) > 1E-9){
Error("Timestep not commensurate with total time");
}
if(verbose){
printfln("Taking %d steps of timestep %.5f, total time %.5f",nt,tstep,ttotal);
}
psi.position(gatelist.front().i1());
Real tot_norm = norm(psi);
Real tsofar = 0;
for(auto tt : range1(nt)){
auto g = gatelist.begin();
while(g != gatelist.end())
{
auto i1 = g->i1();
auto i2 = g->i2();
auto i3 = g->i3();
if(i3){
//print("*"+str(i1)+"-"+str(i2)+"-"+str(i3)+"*");
auto AA=psi(i1)*psi(i2)*psi(i3)*g->gate();
AA.replaceTags("Site,1","Site,0");
auto swp=g->get_swipe();
auto link_tags1 = tags(linkIndex(psi,i1));
auto link_tags2 = tags(linkIndex(psi,i2));
++g;
if(g != gatelist.end()){
//Look ahead to next gate position
auto nr = g->i1();
auto nl = g->i3();
if(!nl)
nl=g->i2();
if(swp=="right")
{
auto [U,S,V] = svd(AA,inds(psi(i1)),args);
if(args.getBool("DoNormalize",false))
S *= 1./itensor::norm(S);
auto ulink=commonIndex(U,S);
auto iset=IndexSet(ulink,siteIndex(psi,i2));
auto [U2,S2,V2] = svd(S*V,iset,args);
if(args.getBool("DoNormalize",false))
S2 *= 1./itensor::norm(S2);
psi.set(i1,U);
psi.set(i2,U2);
psi.set(i3,S2*V2);
//psi.svdBond(i1,AA,Fromleft,args);
auto ulink1=commonIndex(psi(i1),psi(i2));
auto ulink2=commonIndex(psi(i2),psi(i3));
psi.ref(i1).setTags(link_tags1,ulink1);
psi.ref(i2).setTags(link_tags1,ulink1);
psi.ref(i2).setTags(link_tags2,ulink2);
psi.ref(i3).setTags(link_tags2,ulink2);
psi.position(nr);
//does no work if position already ni1
}
else if(swp=="left")
{
auto [U,S,V] = svd(AA,inds(psi(i3)),args);
if(args.getBool("DoNormalize",false))
S *= 1./itensor::norm(S);
auto ulink=commonIndex(U,S);
auto iset=IndexSet(ulink,siteIndex(psi,i2));
auto [U2,S2,V2] = svd(S*V,iset,args);
if(args.getBool("DoNormalize",false))
S2 *= 1./itensor::norm(S2);
psi.set(i3,U);
psi.set(i2,U2);
psi.set(i1,S2*V2);
//psi.svdBond(i1,AA,Fromleft,args);
auto ulink1=commonIndex(psi(i1),psi(i2));
auto ulink2=commonIndex(psi(i2),psi(i3));
psi.ref(i1).setTags(link_tags1,ulink1);
psi.ref(i2).setTags(link_tags1,ulink1);
psi.ref(i2).setTags(link_tags2,ulink2);
psi.ref(i3).setTags(link_tags2,ulink2);
psi.position(nl);
}
else{
Error("You must define swipe direction - left or right");
}
}
else{
auto [U,S,V] = svd(AA,inds(psi(i3)),args);
if(args.getBool("DoNormalize",false))
S *= 1./itensor::norm(S);
auto ulink=commonIndex(U,S);
auto iset=IndexSet(ulink,siteIndex(psi,i2));
auto [U2,S2,V2] = svd(S*V,iset,args);
if(args.getBool("DoNormalize",false))
S2 *= 1./itensor::norm(S2);
psi.set(i3,U);
psi.set(i2,U2);
psi.set(i1,S2*V2);
auto ulink1=commonIndex(psi(i1),psi(i2));
auto ulink2=commonIndex(psi(i2),psi(i3));
psi.ref(i1).setTags(link_tags1,ulink1);
psi.ref(i2).setTags(link_tags1,ulink1);
psi.ref(i2).setTags(link_tags2,ulink2);
psi.ref(i3).setTags(link_tags2,ulink2);
psi.position(i1);
}
}
else{
auto AA = psi(i1)*psi(i2)*g->gate();
AA.replaceTags("Site,1","Site,0");
auto swp=g->get_swipe();
++g;
if(g != gatelist.end())
{
//Look ahead to next gate position
auto nr = g->i1();
auto nl = g->i3();
if(!nl)
nl=g->i2();
//SVD AA to restore MPS form
//before applying current gate
if(swp=="right")
{
psi.svdBond(i1,AA,Fromleft,args);
psi.position(nr); //does no work if position already ni1
}
else if(swp=="left")
{
psi.svdBond(i1,AA,Fromright,args);
psi.position(nl); //does no work if position already ni2
}
else{
Error("You must define swipe direction - left or right");
}
}
else
{
//No next gate to analyze, just restore MPS form
psi.svdBond(i1,AA,Fromright,args);
}
}
}
if(do_normalize)
{
tot_norm *= psi.normalize();
}
tsofar += tstep;
args.add("TimeStepNum",tt);
args.add("Time",tsofar);
args.add("TotalTime",ttotal);
obs.measure(args);
}
if(verbose)
{
printfln("\nTotal time evolved = %.5f\n",tsofar);
}
return tot_norm;
} // gateTEvol
#endif
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