qat.qpus.SimulatedAnnealing

class qat.qpus.SimulatedAnnealing(temp_t, n_steps, seed=None)

A Simulated Annealing solver interfaced as a Quantum Processing Unit (QPU)

Parameters

• temp_t (ArithExpression) – temperature-time dependence. It needs to be specified using a variable t instantiated with the class Variable.

• n_steps (int) – number of annealing time steps in Temp(t) evolution.

• seed (int, optional) – Randomness seed.

submit_job(job)

Execute simulated annealing for a given job.

Parameters

job (Job) – the job to execute

Returns

a result with the solution spin configuration(s)

Return type

result (Result)

qat.simulated_annealing.service.extract_j_and_h_from_obs(obs)

A function to extract the \(J\) coupling matrix, magnetic field \(h\) and Ising energy offset \(E_I\) from the Hamiltonian of an Ising problem. The Hamiltonian should be of the form

\[H = - \sum_{ij} J_{ij} s_i s_j - \sum_i h_i s_i - E_I\]

with \(s_i, s_j \in \{-1,1\}\).

Parameters

obs (Observable) – an observable for an Ising problem

Returns

3-element tuple containing

• J (2D numpy array) - an array with the coupling between each two spins - it represents the \(J\) matrix from the Hamiltonian of the problem

• h (1D numpy array) - an array with the magnetic field acting on each of the spins, coming from the Hamiltonian of the problem

• offset_i (double) - the value of the Ising offset energy in the respective Hamiltonian