| 7 | |
| 8 | |
| 9 | class QAOA: |
| 10 | |
| 11 | def __init__(self, num_elems:int, |
| 12 | hamiltonian_type:str, |
| 13 | hamiltonian_interactions:np.ndarray, |
| 14 | verbose=True): |
| 15 | self.num_elems = num_elems |
| 16 | self.hamiltonian_type = hamiltonian_type |
| 17 | self.hamiltonian_interactions = hamiltonian_interactions |
| 18 | self.verbose = verbose |
| 19 | if self.hamiltonian_type not in ['isling']: |
| 20 | raise ValueError(f"No support for the Hamiltonian type {self.hamiltonian_type}") |
| 21 | self.qubits = [cirq.LineQubit(x) for x in range(num_elems)] |
| 22 | |
| 23 | |
| 24 | @staticmethod |
| 25 | def interaction_gate(q1, q2, gamma=1): |
| 26 | circuit = cirq.Circuit() |
| 27 | circuit.append(cirq.CZ(q1, q2)**gamma) |
| 28 | circuit.append([cirq.X(q2), cirq.CZ(q1, q2)**(-gamma), cirq.X(q2)]) |
| 29 | circuit.append([cirq.X(q1), cirq.CZ(q1, q2) **(-gamma), cirq.X(q1)]) |
| 30 | circuit.append([cirq.X(q1), cirq.X(q2), cirq.CZ(q1, q2) ** gamma, cirq.X(q1), cirq.X(q2)]) |
| 31 | return circuit |
| 32 | |
| 33 | # Build the Target Hamiltonian based circuit Evolution |
| 34 | def target_hamiltonian_evolution_circuit(self, gamma): |
| 35 | circuit = cirq.Circuit() |
| 36 | # Apply the interaction gates to all the qubit pairs |
| 37 | |
| 38 | for i in range(self.num_elems): |
| 39 | |
| 40 | for j in range(i+1, self.num_elems): |
| 41 | circuit.append(self.interaction_gate( |
| 42 | self.qubits[i], self.qubits[j], |
| 43 | gamma=gamma)) |
| 44 | return circuit |
| 45 | |
| 46 | # Build the Starting Hamiltonian based evolution circuit |
| 47 | def starting_hamiltonian_evolution_circuit(self, beta): |
| 48 | for i in range(self.num_elems): |
| 49 | yield cirq.X(self.qubits[i])**beta |
| 50 | |
| 51 | def build_qoaa_circuit(self, gamma_store, beta_store): |
| 52 | self.circuit = cirq.Circuit() |
| 53 | # Hadamard gate on each qubit to get an equal superposition state |
| 54 | print(self.qubits) |
| 55 | self.circuit.append(cirq.H.on_each(self.qubits)) |
| 56 | |
| 57 | for i in range(len(gamma_store)): |
| 58 | self.circuit.append(self.target_hamiltonian_evolution_circuit(gamma_store[i])) |
| 59 | self.circuit.append(self.starting_hamiltonian_evolution_circuit(beta_store[i])) |
| 60 | |
| 61 | def simulate(self): |
| 62 | #print(self.circuit) |
| 63 | sim = cirq.Simulator() |
| 64 | waveform = sim.simulate(self.circuit) |
| 65 | return waveform |
| 66 | |