DmrgJanitor.h

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#ifndef DMRGJANITOR
#define DMRGJANITOR
 
#include "DmrgTypedefs.h"
 
void turnaround (int pivot, size_t L, DMRG::DIRECTION::OPTION &DIR)
{
    if (pivot == L-1 and 
        DIR == DMRG::DIRECTION::RIGHT)
    {
        DIR = DMRG::DIRECTION::LEFT;
    }
    if (pivot == 0 and 
        DIR == DMRG::DIRECTION::LEFT)
    {
        DIR = DMRG::DIRECTION::RIGHT;
    }
}
 
template<typename PivotMatrixType>
class DmrgJanitor
{
public:
    
    DmrgJanitor();
    DmrgJanitor(size_t L_input);
    
 
    void sweep (size_t loc, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H = NULL);
    
    void skim (DMRG::DIRECTION::OPTION DIR, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H = NULL);
    
    void skim (DMRG::BROOM::OPTION TOOL, PivotMatrixType *H = NULL);
    
    void entropy_skim();
    
 
    void sweepStep (DMRG::DIRECTION::OPTION DIR, size_t loc, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H = NULL, bool DISCARD_U_or_V=false);
    
    virtual void rightSweepStep (size_t loc, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H = NULL, bool DISCARD_V=false){};
    
    virtual void leftSweepStep  (size_t loc, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H = NULL, bool DISCARD_U=false){};
    
 
    inline size_t length() const {return N_sites;}
    
 
    double eps_svd, eps_truncWeight, alpha_rsvd;
    size_t max_Nsv, min_Nsv;
    int max_Nrich;
    
    void set_defaultCutoffs();
    
    void set_pivot (int pivot_input) {pivot = pivot_input;};
    
protected:
    
 
    int pivot = -1;
    size_t N_sites;
};
 
template<typename PivotMatrixType>
DmrgJanitor<PivotMatrixType>::
DmrgJanitor()
{
    set_defaultCutoffs();
}
 
template<typename PivotMatrixType>
DmrgJanitor<PivotMatrixType>::
DmrgJanitor (size_t L_input)
:N_sites(L_input)
{
    set_defaultCutoffs();
}
 
template<typename PivotMatrixType>
void DmrgJanitor<PivotMatrixType>::
set_defaultCutoffs()
{
    eps_svd    = DMRG::CONTROL::DEFAULT::eps_svd(0);
    eps_truncWeight = DMRG::CONTROL::DEFAULT::eps_truncWeight(0);
    alpha_rsvd = DMRG::CONTROL::DEFAULT::max_alpha_rsvd(0);
    min_Nsv    = DMRG::CONTROL::DEFAULT::min_Nsv(0);
    max_Nsv    = DMRG::CONTROL::DEFAULT::Mlimit;
    max_Nrich  = DMRG::CONTROL::DEFAULT::max_Nrich(0);
}
 
template<typename PivotMatrixType>
void DmrgJanitor<PivotMatrixType>::
skim (DMRG::DIRECTION::OPTION DIR, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H)
{
    if (DIR == DMRG::DIRECTION::LEFT)
    {
        assert(pivot == N_sites-1 or pivot == -1);
        for (size_t l=N_sites-1; l>0; --l) {sweepStep(DMRG::DIRECTION::LEFT,l,TOOL,H);}
    }
    else
    {
        assert(pivot == 0 or pivot == -1);
        for (size_t l=0; l<N_sites-1; ++l) {sweepStep(DMRG::DIRECTION::RIGHT,l,TOOL,H);}
    }
}
 
template<typename PivotMatrixType>
void DmrgJanitor<PivotMatrixType>::
skim (DMRG::BROOM::OPTION TOOL, PivotMatrixType *H)
{
    assert(pivot == 0 or pivot == N_sites-1);
    
    if (pivot == 0)
    {
        skim(DMRG::DIRECTION::RIGHT,TOOL,H);
    }
    else
    {
        skim(DMRG::DIRECTION::LEFT,TOOL,H);
    }
}
 
template<typename PivotMatrixType>
void DmrgJanitor<PivotMatrixType>::
entropy_skim()
{
    //double eps_svd_bak = eps_svd;
    double eps_truncWeight_bak = eps_truncWeight;
    eps_truncWeight = 0.;
    
    if (pivot == 0)
    {
        skim(DMRG::DIRECTION::RIGHT,DMRG::BROOM::SVD,NULL);
    }
    else
    {
        skim(DMRG::DIRECTION::LEFT,DMRG::BROOM::SVD,NULL);
    }
    
    //eps_svd = eps_svd_bak;
    eps_truncWeight = eps_truncWeight_bak;
}
 
template<typename PivotMatrixType>
void DmrgJanitor<PivotMatrixType>::
sweep (size_t loc, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H)
{
    assert(loc<N_sites);
    if (pivot == -1)
    {
        skim(DMRG::DIRECTION::LEFT,TOOL,H);
        for (size_t l=0; l<loc; ++l) {sweepStep(DMRG::DIRECTION::RIGHT,l,TOOL,H);}
    }
    else if (pivot!=-1 and pivot<loc)
    {
        for (size_t l=pivot; l<loc; ++l) {sweepStep(DMRG::DIRECTION::RIGHT,l,TOOL,H);}
    }
    else if (pivot!=-1 and pivot>loc)
    {
        for (size_t l=pivot; l>loc; --l) {sweepStep(DMRG::DIRECTION::LEFT,l,TOOL,H);}
    }
}
 
template<typename PivotMatrixType>
inline void DmrgJanitor<PivotMatrixType>::
sweepStep (DMRG::DIRECTION::OPTION DIR, size_t loc, DMRG::BROOM::OPTION TOOL, PivotMatrixType *H, bool DISCARD_U_or_V)
{
    (DIR==DMRG::DIRECTION::LEFT)? leftSweepStep(loc,TOOL,H,DISCARD_U_or_V) : rightSweepStep(loc,TOOL,H,DISCARD_U_or_V);
}
 
#endif