Environment BoundaryMPS

Boundary MPS approach for contracting finite lattice. It supports expectation values, including long-range correlations, sampling, etc.

class yastn.tn.fpeps.EnvBoundaryMPS(psi, opts_svd, setup='l', opts_var=None)

Boundary MPS class for finite PEPS contraction.

measure_1site(O)

Calculate all 1-point expectation values <O_j> in a finite PEPS.

Takes CTM environments and operators.

Parameters:

O (dict[tuple[int, int], dict[int, operators]]) – mapping sites with list of operators at each site.

measure_2site(O, P, opts_svd, opts_var=None)

Calculate all 2-point correlations <O_i P_j> in a finite PEPS.

Takes CTM environments and operators.

Parameters:

O, P (dict[tuple[int, int], dict[int, operators]],) – mapping sites with list of operators at each site.

sample(projectors, opts_svd=None, opts_var=None)

Sample a random configuration from a finite PEPS.

Takes CTM environments and a complete list of projectors to sample from.

sample_MC_(st0, st1, st2, psi, projectors, opts_svd, opts_var, trial='local')

Monte Carlo steps in a finite peps. Makes two steps while sweeping finite lattice back and forth.

Takes environments and a complete list of projectors to sample from.

proj_env, st1, st2 are updated in place