QAOA evaluate circuit

[raulconchello]

Implementation of qaoa.evaluate_circuit method

• [x] New qaoa.evaluate_circuit method
  • [x] It accepts list of parameters
  • [x] It accepts dict of parameters
  • [x] If the input different than list or dict, it raises an error
  • [x] The method can be called without optimizing the object only if list or dict is passed
• [x] For variational params, implement update_from_dict method, so a dict can be passed to run evaluate_circuit
• [x] For variational params, implement asdict method, the counterpart of update_from_dict method
• [x] tests for all the points above

Example

We get some optimized parameters, using -in this case- analytical simulator

from openqaoa.problems import QUBO
from openqaoa import QAOA
from openqaoa.backends import create_device

#create random problem
problem = QUBO.random_instance(6)

#create qaoa object, with analytical simulator
q_analytic = QAOA()
device = create_device(location='local', name='analytical_simulator')
q_analytic.set_device(device)
q_analytic.set_circuit_properties(p=1, param_type='standard', init_type='rand', mixer_hamiltonian='x')
q_analytic.set_classical_optimizer(maxiter=100, method='vgd', jac="finite_difference")

#compile and optimize
q_analytic.compile(problem)
q_analytic.optimize()

opt_params = q_analytic.result.optimized['angles']
print(opt_params)

[Out]: [0.587019236113, 249.611957397334]

Now we evaluate a qaoa circuit with a QPU or simulator using the optimized parameters found above.

#create qaoa object, with shot simulator
q_shots = QAOA()
device = create_device(location='local', name='qiskit.shot_simulator')
q_shots.set_device(device)
q_shots.set_circuit_properties(p=1, param_type='standard', init_type='rand', mixer_hamiltonian='x')
q_shots.set_classical_optimizer(maxiter=100, method='vgd', jac="finite_difference")

#compile (we don't optimize)
q_shots.compile(problem)

#evaluate the qaoa circuit with the optimized parameters
results_eval_circuit = q_shots.evaluate_circuit(opt_params)
print(results_eval_circuit)

_[Out]: { 'cost': -44.783801067124, 'uncertainty': 103.578710845481, 'counts': {...} }

[codecov[bot]]

Codecov Report

Merging #192 (932d1cd) into dev (54d0c70) will increase coverage by 0.73%. The diff coverage is 99.53%.

@@            Coverage Diff             @@
##              dev     #192      +/-   ##
==========================================
+ Coverage   88.81%   89.54%   +0.73%     
==========================================
  Files          32       33       +1     
  Lines        5812     6237     +425     
==========================================
+ Hits         5162     5585     +423     
- Misses        650      652       +2     

Impacted Files	Coverage Δ
tests/test_notebooks.py	94.00% <66.66%> (-1.75%)	:arrow_down:
tests/test_benchmark.py	99.59% <99.59%> (ø)
tests/test_analytical_simulator.py	100.00% <100.00%> (ø)
tests/test_parameters.py	99.70% <100.00%> (+0.06%)	:arrow_up:
tests/test_utilities.py	99.42% <100.00%> (ø)
tests/test_workflows.py	99.56% <100.00%> (+0.06%)	:arrow_up:

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[Q-lds]

Let's remember to close Issue https://github.com/entropicalabs/openqaoa/issues/186 once this PR is merged!

[vishal-ph]

NOTE: run black formatter before merging