cytnx::Bond Class Reference

the object contains auxiliary properties for each Tensor rank (bond) More...

#include <Bond.hpp>

Public Member Functions
	Bond (const cytnx_uint64 &dim, const bondType &bd_type=bondType::BD_REG, const std::vector< std::vector< cytnx_int64 > > &in_qnums={}, const std::vector< Symmetry > &in_syms={})
void	Init (const cytnx_uint64 &dim, const bondType &bd_type=bondType::BD_REG, const std::vector< std::vector< cytnx_int64 > > &in_qnums={}, const std::vector< Symmetry > &in_syms={})
	init a bond object
bondType	type () const
	return the current tag type
const std::vector< std::vector< cytnx_int64 > > &	qnums () const
	return the current quantum number set(s) by reference
std::vector< std::vector< cytnx_int64 > > &	qnums ()
std::vector< std::vector< cytnx_int64 > >	qnums_clone () const
	return copy of the current quantum number set(s)
cytnx_uint64	dim () const
	return the dimension of the bond
cytnx_uint32	Nsym () const
	return the number of symmetries
const std::vector< Symmetry > &	syms () const
	return the vector of symmetry objects by reference.
std::vector< Symmetry > &	syms ()
std::vector< Symmetry >	syms_clone () const
	return copy of the vector of symmetry objects.
Bond &	set_type (const bondType &new_bondType)
	change the tag-type of the instance Bond
Bond	retype (const bondType &new_bondType)
	create a new instance of Bond with type changed to the new tag-type:
Bond	redirect () const
	create a new instance of Bond with type changed in btwn BRA / KET:
void	clear_type ()
	change the tag-type to the default value BD_REG
Bond	clone () const
	return a copy of the instance Bond
void	combineBond_ (const Bond &bd_in)
	combine the input bond with self, inplacely
Bond	combineBond (const Bond &bd_in) const
	combine the input bond with self, and return a new combined Bond instance.
Bond	combineBonds (const std::vector< Bond > &bds)
	combine multiple input bonds with self, and return a new combined Bond instance.
void	combineBonds_ (const std::vector< Bond > &bds)
	combine multiple input bonds with self, inplacely
std::vector< std::vector< cytnx_int64 > >	getUniqueQnums (std::vector< cytnx_uint64 > &counts)
	return a sorted qnum sets by removing all the duplicate qnum sets.
std::vector< std::vector< cytnx_int64 > >	getUniqueQnums ()
cytnx_uint64	getDegeneracy (const std::vector< cytnx_int64 > &qnum) const
	return the degeneracy of specify qnum set.
cytnx_uint64	getDegeneracy (const std::vector< cytnx_int64 > &qnum, std::vector< cytnx_uint64 > &indices) const
std::vector< std::vector< cytnx_int64 > >	calc_reverse_qnums ()
void	Save (const std::string &fname) const
void	Save (const char *fname) const
bool	operator== (const Bond &rhs) const
bool	operator!= (const Bond &rhs) const
Bond	operator* (const Bond &rhs) const
Bond &	operator*= (const Bond &rhs)

Static Public Member Functions
static cytnx::Bond	Load (const std::string &fname)
static cytnx::Bond	Load (const char *fname)

Detailed Description

the object contains auxiliary properties for each Tensor rank (bond)

Constructor & Destructor Documentation

Bond()

cytnx::Bond::Bond ( const cytnx_uint64 &  dim, const bondType &  bd_type = bondType::BD_REG, const std::vector< std::vector< cytnx_int64 > > &  in_qnums = {}, const std::vector< Symmetry > &  in_syms = {}  )

inline

Member Function Documentation

calc_reverse_qnums()

std::vector< std::vector< cytnx_int64 > > cytnx::Bond::calc_reverse_qnums ( )

inline

clear_type()

void cytnx::Bond::clear_type ( )

inline

change the tag-type to the default value BD_REG

clone()

Bond cytnx::Bond::clone ( ) const

inline

return a copy of the instance Bond

Returns

[Bond] a new instance of Bond that have the same contents

Example:

c++ API:

#include "cytnx.hpp"
#include <iostream>
 
using namespace std;
using namespace cytnx;
 
int main(){ 
 
    /* 1.
        create a non-symmetry, regular bond (BD_REG) 
        with dimension 10
    */
    Bond bd_a = Bond(10);
    cout << bd_a << endl;
 
    Bond bd_b = bd_a;
    Bond bd_c = bd_a.clone();
 
    cout << is(bd_b,bd_a) << endl; //true, the same instance
    cout << is(bd_c,bd_a) << endl; //false, different instance
 
    cout << (bd_b == bd_a) << endl; //true, same content
    cout << (bd_c == bd_a) << endl; //true, same content
 
    return 0;
 
}
 

output>

Dim = 10 |type: REGULAR 

1
0
1
1

python API:

from cytnx import *
 
bd_a = Bond(10)
print(bd_a)
 
bd_b = bd_a;
bd_c = bd_a.clone();
 
print(bd_b is bd_a) #true
print(bd_c is bd_a) #false
print(bd_b == bd_a) #true
print(bd_c == bd_a) #true

output>

Dim = 10 |type: REGULAR 


True
False
True
True

combineBond()

Bond cytnx::Bond::combineBond ( const Bond &  bd_in ) const

inline

combine the input bond with self, and return a new combined Bond instance.

Parameters

bd_in

the bond that to be combined.

Returns

[Bond] a new combined bond instance.

Example:

c++ API:

#include "cytnx.hpp"
#include <iostream>
 
 
using namespace cytnx;
using namespace std;
int main(){ 
 
    /* 1.
        create a non-symmetry, regular bond (BD_REG) 
        with dimension 10
    */
    Bond bd_a = Bond(10,BD_KET);
    Bond bd_b = Bond(15,BD_KET);
    Bond bd_c = bd_a.combineBond(bd_b);
    cout << bd_c << endl;
    cout << bd_a << endl;
    cout << bd_b << endl;
 
    /* 2.
        combine symmetry bonds, 
        with U1 x Z2 multiple symmetry 
    */
    Bond bd_d = Bond(3,BD_BRA,{{0,1},{2,0},{-4,1}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
                                
    Bond bd_e = Bond(4,BD_BRA,{{0,0},{2,1},{-1,1},{3,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
 
    Bond bd_f = bd_d.combineBond(bd_e);
    cout << bd_f << endl;
    cout << bd_d << endl;
    cout << bd_e << endl;
    return 0;
    
 
 
}
 

output>

Dim = 150 |type: KET>     

Dim = 10 |type: KET>     

Dim = 15 |type: KET>     

Dim = 12 |type: <BRA     
 U1::  +0 +2 -1 +3 +2 +4 +1 +5 -4 -2 -5 -1
 Z2::  +1 +0 +0 +1 +0 +1 +1 +0 +1 +0 +0 +1

Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1

Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

python API:

from cytnx import *
 
bd_a = Bond(10,BD_KET)
bd_b = Bond(15,BD_KET)
bd_c = bd_a.combineBond(bd_b)
print(bd_a)
print(bd_b)
print(bd_c)
 
 
bd_d = Bond(3,BD_BRA,[[0,1],[2,0],[-4,1]],
                      [Symmetry.U1(),
                       Symmetry.Zn(2)])
                                
bd_e = Bond(4,BD_BRA,[[0,0],[2,1],[-1,1],[3,0]],
                      [Symmetry.U1(),
                       Symmetry.Zn(2)])
 
bd_f = bd_d.combineBond(bd_e)
print(bd_f)
print(bd_d)
print(bd_e)

output>

Dim = 10 |type: KET>     


Dim = 15 |type: KET>     


Dim = 150 |type: KET>     


Dim = 12 |type: <BRA     
 U1::  +0 +2 -1 +3 +2 +4 +1 +5 -4 -2 -5 -1
 Z2::  +1 +0 +0 +1 +0 +1 +1 +0 +1 +0 +0 +1


Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1


Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

combineBond_()

void cytnx::Bond::combineBond_ ( const Bond &  bd_in )

inline

combine the input bond with self, inplacely

Parameters

bd_in

the bond that to be combined with self.

Example:

c++ API:

#include "cytnx.hpp"
#include <iostream>
 
 
using namespace cytnx;
using namespace std;
int main(){ 
 
    /* 1.
        create a non-symmetry, regular bond (BD_REG) 
        with dimension 10
    */
    Bond bd_a = Bond(10);
    cout << bd_a << endl;
 
    Bond bd_b = Bond(5);
    cout << bd_b << endl;
 
 
    bd_a.combineBond_(bd_b);
    cout << bd_a << endl;
 
 
    /* 2.
        combine symmetry bonds, 
        with U1 x Z2 multiple symmetry 
    */
    Bond bd_c = Bond(3,BD_BRA,{{0,1},{2,0},{-4,1}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
                                
                                
    cout << bd_c << endl;
 
    Bond bd_d = Bond(4,BD_BRA,{{0,0},{2,1},{-1,1},{3,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
    cout << bd_d << endl;
 
    
    bd_c.combineBond_(bd_d);
    cout << bd_c << endl;
 
    return 0;
    
 
 
}
 

output>

Dim = 10 |type: REGULAR 

Dim = 5 |type: REGULAR 

Dim = 50 |type: REGULAR 

Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1

Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

Dim = 12 |type: <BRA     
 U1::  +0 +2 -1 +3 +2 +4 +1 +5 -4 -2 -5 -1
 Z2::  +1 +0 +0 +1 +0 +1 +1 +0 +1 +0 +0 +1

python API:

from cytnx import *
bd_a = Bond(10)
print(bd_a)
 
bd_b = Bond(5)
print(bd_b)
 
bd_a.combineBond_(bd_b)
print(bd_a)
 
 
bd_c = Bond(3,BD_BRA,[[0,1],[2,0],[-4,1]],
                      [Symmetry.U1(),
                       Symmetry.Zn(2)])
                                
print(bd_c)                                
 
bd_d = Bond(4,BD_BRA,[[0,0],[2,1],[-1,1],[3,0]],
                      [Symmetry.U1(),
                       Symmetry.Zn(2)])
print(bd_d)
    
bd_c.combineBond_(bd_d)
print(bd_c)
 

output>

Dim = 10 |type: REGULAR 


Dim = 5 |type: REGULAR 


Dim = 50 |type: REGULAR 


Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1


Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0


Dim = 12 |type: <BRA     
 U1::  +0 +2 -1 +3 +2 +4 +1 +5 -4 -2 -5 -1
 Z2::  +1 +0 +0 +1 +0 +1 +1 +0 +1 +0 +0 +1

combineBonds()

Bond cytnx::Bond::combineBonds ( const std::vector< Bond > &  bds )

inline

combine multiple input bonds with self, and return a new combined Bond instance.

Parameters

bds	the bonds that to be combined with self.

Returns

[Bond] a new combined bond instance.

Example:

c++ API:

#include "cytnx.hpp"
#include <iostream>
 
 
using namespace cytnx;
using namespace std;
int main(){ 
 
    /* 1.
        combine multiple KET bonds
    */
    Bond bd_a = Bond(10,BD_KET);
    Bond bd_b = Bond(4,BD_KET);
    Bond bd_c = Bond(5,BD_KET);
    Bond bd_d = Bond(2,BD_KET);
    
    // note that this will not create copy instances for each Bond elements.
    // so it is both memory efficient and fast!
    Bond bd_all = bd_a.combineBonds({bd_b,bd_c,bd_d});
    
    cout << bd_a << endl;
    cout << bd_b << endl;
    cout << bd_c << endl;   
    cout << bd_d << endl;
    cout << bd_all << endl;
 
 
    /* 2.
        combine symmetry bonds, 
        with U1 x Z2 multiple symmetry 
    */
    Bond bd_sym_a = Bond(3,BD_BRA,{{0,1},
                                   {2,0},
                                   {-4,1}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
                                
    Bond bd_sym_b = Bond(4,BD_BRA,{{0 ,0},
                                   {2 ,1},
                                   {-1,1},
                                   {3 ,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
 
    Bond bd_sym_c = Bond(5,BD_BRA,{{1 ,1},
                                   {1 ,1},
                                   {-1,1},
                                   {-2,0},
                                   {0 ,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
 
    Bond bd_sym_d = bd_sym_a.combineBonds({bd_sym_b,bd_sym_c});
    cout << bd_sym_a << endl;
    cout << bd_sym_b << endl;
    cout << bd_sym_c << endl;
    cout << bd_sym_d << endl;
 
    return 0;
    
 
 
}
 

output>

Dim = 10 |type: KET>     

Dim = 4 |type: KET>     

Dim = 5 |type: KET>     

Dim = 2 |type: KET>     

Dim = 400 |type: KET>     

Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1

Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

Dim = 5 |type: <BRA     
 U1::  +1 +1 -1 -2 +0
 Z2::  +1 +1 +1 +0 +0

Dim = 60 |type: <BRA     
 U1::  +1 +1 -1 -2 +0 +3 +3 +1 +0 +2 +0 +0 -2 -3 -1 +4 +4 +2 +1 +3 +3 +3 +1 +0 +2 +5 +5 +3 +2 +4 +2 +2 +0 -1 +1 +6 +6 +4 +3 +5 -3 -3 -5 -6 -4 -1 -1 -3 -4 -2 -4 -4 -6 -7 -5 +0 +0 -2 -3 -1
 Z2::  +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1

python API:

from cytnx import *
 
bd_a = Bond(10,BD_KET);
bd_b = Bond(4,BD_KET);
bd_c = Bond(5,BD_KET);
bd_d = Bond(2,BD_KET);
 
bd_all = bd_a.combineBonds([bd_b,bd_c,bd_d]);
    
print( bd_a )
print( bd_b )
print( bd_c )   
print( bd_d )
print( bd_all )
 
 
bd_sym_a = Bond(3,BD_BRA,[[0,1],
                          [2,0],
                          [-4,1]],
                          [Symmetry.U1(),
                           Symmetry.Zn(2)]);
                            
bd_sym_b = Bond(4,BD_BRA,[[0 ,0],
                          [2 ,1],
                          [-1,1],
                          [3 ,0]],
                          [Symmetry.U1(),
                           Symmetry.Zn(2)]);
 
bd_sym_c = Bond(5,BD_BRA,[[1 ,1],
                          [1 ,1],
                          [-1,1],
                          [-2,0],
                          [0 ,0]],
                          [Symmetry.U1(),
                           Symmetry.Zn(2)]);
 
bd_sym_d = bd_sym_a.combineBonds([bd_sym_b,bd_sym_c]);
print( bd_sym_a )
print( bd_sym_b )
print( bd_sym_c )
print( bd_sym_d )
 

output>

Dim = 10 |type: KET>     


Dim = 4 |type: KET>     


Dim = 5 |type: KET>     


Dim = 2 |type: KET>     


Dim = 400 |type: KET>     


Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1


Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0


Dim = 5 |type: <BRA     
 U1::  +1 +1 -1 -2 +0
 Z2::  +1 +1 +1 +0 +0


Dim = 60 |type: <BRA     
 U1::  +1 +1 -1 -2 +0 +3 +3 +1 +0 +2 +0 +0 -2 -3 -1 +4 +4 +2 +1 +3 +3 +3 +1 +0 +2 +5 +5 +3 +2 +4 +2 +2 +0 -1 +1 +6 +6 +4 +3 +5 -3 -3 -5 -6 -4 -1 -1 -3 -4 -2 -4 -4 -6 -7 -5 +0 +0 -2 -3 -1
 Z2::  +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1

combineBonds_()

void cytnx::Bond::combineBonds_ ( const std::vector< Bond > &  bds )

inline

combine multiple input bonds with self, inplacely

Parameters

bds	the bonds that to be combined with self.

Example:

c++ API:

#include "cytnx.hpp"
#include <iostream>
 
 
using namespace cytnx;
using namespace std;
int main(){ 
 
    /* 1.
        combine multiple KET bonds
    */
    Bond bd_a = Bond(10,BD_KET);
    Bond bd_b = Bond(4,BD_KET);
    Bond bd_c = Bond(5,BD_KET);
    Bond bd_d = Bond(2,BD_KET);
    cout << bd_a << endl;
    cout << bd_b << endl;
    cout << bd_c << endl;   
    cout << bd_d << endl;
    
    bd_a.combineBonds_({bd_b,bd_c,bd_d});
    cout << bd_a << endl;
 
 
    /* 2.
        combine symmetry bonds, 
        with U1 x Z2 multiple symmetry 
    */
    Bond bd_sym_a = Bond(3,BD_BRA,{{0,1},
                                   {2,0},
                                   {-4,1}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
                                
    Bond bd_sym_b = Bond(4,BD_BRA,{{0 ,0},
                                   {2 ,1},
                                   {-1,1},
                                   {3 ,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
 
    Bond bd_sym_c = Bond(5,BD_BRA,{{1 ,1},
                                   {1 ,1},
                                   {-1,1},
                                   {-2,0},
                                   {0 ,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
    
    cout << bd_sym_a << endl;
    cout << bd_sym_b << endl;
    cout << bd_sym_c << endl;
    bd_sym_a.combineBonds_({bd_sym_b,bd_sym_c});
    cout << bd_sym_a << endl;
 
    return 0;
    
 
 
}
 

output>

Dim = 10 |type: KET>     

Dim = 4 |type: KET>     

Dim = 5 |type: KET>     

Dim = 2 |type: KET>     

Dim = 400 |type: KET>     

Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1

Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

Dim = 5 |type: <BRA     
 U1::  +1 +1 -1 -2 +0
 Z2::  +1 +1 +1 +0 +0

Dim = 60 |type: <BRA     
 U1::  +1 +1 -1 -2 +0 +3 +3 +1 +0 +2 +0 +0 -2 -3 -1 +4 +4 +2 +1 +3 +3 +3 +1 +0 +2 +5 +5 +3 +2 +4 +2 +2 +0 -1 +1 +6 +6 +4 +3 +5 -3 -3 -5 -6 -4 -1 -1 -3 -4 -2 -4 -4 -6 -7 -5 +0 +0 -2 -3 -1
 Z2::  +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1

python API:

from cytnx import *
 
bd_a = Bond(10,BD_KET);
bd_b = Bond(4,BD_KET);
bd_c = Bond(5,BD_KET);
bd_d = Bond(2,BD_KET);
print( bd_a )
print( bd_b )
print( bd_c )   
print( bd_d )
 
bd_a.combineBonds_([bd_b,bd_c,bd_d]);
print( bd_a )
 
 
bd_sym_a = Bond(3,BD_BRA,[[0,1],
                          [2,0],
                          [-4,1]],
                          [Symmetry.U1(),
                           Symmetry.Zn(2)]);
                            
bd_sym_b = Bond(4,BD_BRA,[[0 ,0],
                          [2 ,1],
                          [-1,1],
                          [3 ,0]],
                          [Symmetry.U1(),
                           Symmetry.Zn(2)]);
 
bd_sym_c = Bond(5,BD_BRA,[[1 ,1],
                          [1 ,1],
                          [-1,1],
                          [-2,0],
                          [0 ,0]],
                          [Symmetry.U1(),
                           Symmetry.Zn(2)]);
 
print( bd_sym_a )
print( bd_sym_b )
print( bd_sym_c )
bd_sym_a.combineBonds_([bd_sym_b,bd_sym_c]);
print( bd_sym_a )

output>

Dim = 10 |type: KET>     


Dim = 4 |type: KET>     


Dim = 5 |type: KET>     


Dim = 2 |type: KET>     


Dim = 400 |type: KET>     


Dim = 3 |type: <BRA     
 U1::  +0 +2 -4
 Z2::  +1 +0 +1


Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0


Dim = 5 |type: <BRA     
 U1::  +1 +1 -1 -2 +0
 Z2::  +1 +1 +1 +0 +0


Dim = 60 |type: <BRA     
 U1::  +1 +1 -1 -2 +0 +3 +3 +1 +0 +2 +0 +0 -2 -3 -1 +4 +4 +2 +1 +3 +3 +3 +1 +0 +2 +5 +5 +3 +2 +4 +2 +2 +0 -1 +1 +6 +6 +4 +3 +5 -3 -3 -5 -6 -4 -1 -1 -3 -4 -2 -4 -4 -6 -7 -5 +0 +0 -2 -3 -1
 Z2::  +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1 +1 +1 +1 +0 +0 +1 +1 +1 +0 +0 +0 +0 +0 +1 +1

dim()

cytnx_uint64 cytnx::Bond::dim ( ) const

inline

return the dimension of the bond

Returns

[cytnx_uint64]

getDegeneracy() [1/2]

cytnx_uint64 cytnx::Bond::getDegeneracy ( const std::vector< cytnx_int64 > &  qnum ) const

inline

return the degeneracy of specify qnum set.

Returns

degeneracy

[Note]

if the bond has no symmetries, return 0.

getDegeneracy() [2/2]

cytnx_uint64 cytnx::Bond::getDegeneracy ( const std::vector< cytnx_int64 > &  qnum, std::vector< cytnx_uint64 > &  indices  ) const

inline

getUniqueQnums() [1/2]

std::vector< std::vector< cytnx_int64 > > cytnx::Bond::getUniqueQnums ( )

inline

getUniqueQnums() [2/2]

std::vector< std::vector< cytnx_int64 > > cytnx::Bond::getUniqueQnums ( std::vector< cytnx_uint64 > &  counts )

inline

return a sorted qnum sets by removing all the duplicate qnum sets.

Returns

unique_qnums

Init()

void cytnx::Bond::Init ( const cytnx_uint64 &  dim, const bondType &  bd_type = bondType::BD_REG, const std::vector< std::vector< cytnx_int64 > > &  in_qnums = {}, const std::vector< Symmetry > &  in_syms = {}  )

inline

init a bond object

Parameters

dim	the dimension of the bond (rank)
bd_type	the tag of the bond, it can be BD_BRA, BD_KET as physical tagged; or BD_REG as regular bond (rank)
in_qnums	the quantum number(s) of the bond. it should be a 2d vector with shape (# of symmetry, dim)
in_syms	the symmetry object of the bond. [Note] if qnums are provided, the default symmetry type is Symmetry::U1

description:

1. each bond can be tagged with BD_BRA or BD_KET that represent the bond is defined in Bra space or Ket space.
2. the bond can have arbitrary multiple symmetries, with the type of each symmetry associate to the qnums are provided with the in_syms.

[Note]

1. if quantum number(s) are provided (which means the bond is with symmetry) then the bond MUST be tagged with either BD_BRA or BD_KET
2. if the bond is non-symmetry, then it can be tagged with BD_BRA or BD_KET, or BD_REG depending on the usage.

Example:

c++ API:

#include "cytnx.hpp"
#include <iostream>
 
 
using namespace cytnx;
using namespace std;
int main(){ 
 
    /* 1.
        create a non-symmetry, regular bond (BD_REG) 
        with dimension 10
    */
    Bond bd_a = Bond(10);
    cout << bd_a << endl;
 
    /* 2. 
        create a non-symmetry bond tagged with BD_KET 
        with dimension 10
    */
    Bond bd_b = Bond(10,BD_KET);
    cout << bd_b << endl;
 
    /* 3.
        crate a symmetry bond, 
        with single U1 (default) symmetry and qnums = (0,2,-1,3)
    */
    Bond bd_c = Bond(4,BD_KET,{{0},{2},{-1},{3}});
    cout << bd_c << endl;
 
    /* 3.
        crate a symmetry bond, 
        with U1 x Z2 multiple symmetry 
        and qnums = U1:(0,2,-1,3) x Z2:(0,1,1,0)
    */
    Bond bd_d = Bond(4,BD_BRA,{{0 ,0},
                               {2 ,1},
                               {-1,1},
                               {3 ,0}},
                              {Symmetry::U1(),
                               Symmetry::Zn(2)});
    cout << bd_d << endl;
 
    
    
 
 
}
 

output>

Dim = 10 |type: REGULAR 

Dim = 10 |type: KET>     

Dim = 4 |type: KET>     
 U1::  +0 +2 -1 +3

Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

python API:

from cytnx import *
 
bd_a = Bond(10)
print(bd_a)
 
bd_b = Bond(10,BD_KET)
print(bd_b)
 
bd_c = Bond(4,BD_KET,[[0],[2],[-1],[3]])
print(bd_c)
 
bd_d = Bond(4,BD_BRA,[[0 ,0],
                      [2 ,1],
                      [-1,1],
                      [3 ,0]],
                     [Symmetry.U1(),
                      Symmetry.Zn(2)])
 
print(bd_d)
 
    

output>

Dim = 10 |type: REGULAR 


Dim = 10 |type: KET>     


Dim = 4 |type: KET>     
 U1::  +0 +2 -1 +3


Dim = 4 |type: <BRA     
 U1::  +0 +2 -1 +3
 Z2::  +0 +1 +1 +0

Load() [1/2]

Bond cytnx::Bond::Load ( const char *  fname )

static

Load() [2/2]

Bond cytnx::Bond::Load ( const std::string &  fname )

static

Nsym()

cytnx_uint32 cytnx::Bond::Nsym ( ) const

inline

return the number of symmetries

Returns

[cytnx_uint32]

operator!=()

bool cytnx::Bond::operator!=

(

const Bond &

rhs

)

const

operator*()

Bond cytnx::Bond::operator* ( const Bond &  rhs ) const

inline

operator*=()

Bond & cytnx::Bond::operator*= ( const Bond &  rhs )

inline

operator==()

bool cytnx::Bond::operator==

(

const Bond &

rhs

)

const

qnums() [1/2]

std::vector< std::vector< cytnx_int64 > > & cytnx::Bond::qnums ( )

inline

qnums() [2/2]

const std::vector< std::vector< cytnx_int64 > > & cytnx::Bond::qnums ( ) const

inline

return the current quantum number set(s) by reference

Returns

[2d vector] with shape: (dim, # of Symmetry)

qnums_clone()

std::vector< std::vector< cytnx_int64 > > cytnx::Bond::qnums_clone ( ) const

inline

return copy of the current quantum number set(s)

Returns

[2d vector] with shape: (dim, # of Symmetry)

redirect()

Bond cytnx::Bond::redirect ( ) const

inline

create a new instance of Bond with type changed in btwn BRA / KET:

retype()

Bond cytnx::Bond::retype ( const bondType &  new_bondType )

inline

create a new instance of Bond with type changed to the new tag-type:

Parameters

new_bondType

the new tag-type, it can be BD_BRA,BD_KET or BD_REG

[Note] This is equivalent to Bond.clone().set_type()

Save() [1/2]

void cytnx::Bond::Save

(

const char *

fname

)

const

Save() [2/2]

void cytnx::Bond::Save

(

const std::string &

fname

)

const

set_type()

Bond & cytnx::Bond::set_type ( const bondType &  new_bondType )

inline

change the tag-type of the instance Bond

Parameters

new_bondType

the new tag-type, it can be BD_BRA,BD_KET or BD_REG

syms() [1/2]

std::vector< Symmetry > & cytnx::Bond::syms ( )

inline

syms() [2/2]

const std::vector< Symmetry > & cytnx::Bond::syms ( ) const

inline

return the vector of symmetry objects by reference.

Returns

[vector of Symmetry]

syms_clone()

std::vector< Symmetry > cytnx::Bond::syms_clone ( ) const

inline

return copy of the vector of symmetry objects.

Returns

[vector of Symmetry]

type()

bondType cytnx::Bond::type ( ) const

inline

return the current tag type

Returns

[bondType] can be BD_BRA, BD_KET or BD_REG

---

The documentation for this class was generated from the following files:

• include/Bond.hpp
• src/Bond.cpp