1-site C4v Environment¶
-
class
ctm.one_site_c4v.env_c4v.
ENV_C4V
(chi, state=None, bond_dim=None, ctm_args=<config.CTMARGS object>, global_args=<config.GLOBALARGS object>)[source]¶ - Parameters
chi (int) – environment bond dimension \(\chi\)
state (IPEPS_C4V) – wavefunction
bond_dim2 – bond dimension
ctm_args (CTMARGS) – CTM algorithm configuration
global_args (GLOBALARGS) – global configuration
Assuming C4v symmetric single-site
state
create corresponding half-row(column) tensor T and corner tensor C. The corner tensor has dimensions \(\chi \times \chi\) and the half-row(column) tensor has dimensions \(\chi \times \chi \times D^2\) with \(D\) given bystate
orbond_dim
:y\x -1 0 1 -1 C T C 0 T A T 1 C T C
If both
state
andbond_dim
are supplied, thebond_dim
parameter is ignored.The environment tensors of an ENV object
e
are accesed through membersC
andT
The index-position convention is as follows: For upper left C and left T start from the index in the direction “up” <=> (-1,0) and continue anti-clockwise:C--1 0--T--1 0--C | | | 0 2 1 0 0 | | T--2 2--T | | 1 1 0 2 0 | | | C--1 0--T--1 1--C
All C’s and T’s in the above diagram are identical and they are symmetric under the exchange of environment bond indices \(C_{ij}=C_{ji}\) and \(T_{ija}=C_{jia}\).
-
ctm.one_site_c4v.env_c4v.
init_env
(state, env, ctm_args=<config.CTMARGS object>)[source]¶ - Parameters
Initializes the environment env according to one of the supported options specified inside
CTMARGS.ctm_env_init_type
CONST - C and T tensors have all their elements intialized to a value 1
RANDOM - C and T tensors have elements with random numbers drawn from uniform distribution [0,1)
CTMRG - tensors C and T are built from the on-site tensor of state