aux

Auxliary functions to load and operate on couplings.

tnac4o.auxx.Jij_f2p(J)

Change 1-base indexig to 0-base indexing in a list of Jij couplings.

Class tnac4o expects 0-based indexing.

Parameters:J (list) – a list of couplings with elements in the format [i, j, Jij]. Returns:a list of [i-1, j-1, Jij].

tnac4o.auxx.energy_Jij(J, states)

Calculate energies from bit_strings for Ising model.

Parameters:

• J (list) – a list of couplings with elements in the format [i, j, Jij]
• states (nparray) – used encoding: 1 (spin up \(s_i=+1\)), 0 (spin down \(s_i=-1\))

Returns:

1d numpy array with energies of all states.

tnac4o.auxx.energy_RMF(J, states)

Calculate cost function for bit_string for RMF.

Parameters:

• J (dict) – dictionary encoding the cost function as factored graph on 2d rectangular lattice, see tnac4o.tnac4o() for used conventions.
• states (nparray) – configurations

Returns:

1d numpy array with energies for all states.

tnac4o.auxx.load_Jij(file_name)

Loads couplings of the Ising model/problem from a file.

Parameters:file_name (str) – a path to file with coupling written in the format where each line contains i, j, Jij. Returns:a list of couplings with elements in the format [i, j, Jij].

tnac4o.auxx.minus_Jij(J)

Change sign of all Jij couplings.

Parameters:J (list) – a list of couplings with elements in the format [i, j, Jij]. Returns:a list of [i, j, -Jij].

tnac4o.auxx.round_Jij(J, dJ)

Round couplings to multiplies of dJ.

Parameters:J (list) – a list of couplings with elements in the format [i, j, Jij]. Returns:a list of [i, j, rJij] couplings, where rJij = round(Jij/dJ)*dJ