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final-qibotn/src/qibotn/quimb.py
2023-02-16 08:24:06 +01:00

40 lines
1.0 KiB
Python

import numpy as np
import quimb.tensor as qtn
from qibo.models import Circuit as QiboCircuit
def from_qibo(circuit: QiboCircuit, psi0=None):
nqubits = circuit.nqubits
tncirc = qtn.Circuit(nqubits, psi0=psi0)
for gate in circuit.queue:
tncirc.apply_gate(
gate.name,
*gate.parameters,
*gate.qubits,
parametrize=len(gate.parameters) > 0
)
return tncirc
def init_state_tn(nqubits, init_state_sv):
dims = tuple(2 * np.ones(nqubits, dtype=int))
return qtn.tensor_1d.MatrixProductState.from_dense(init_state_sv, dims)
def eval(qasm: str, init_state, backend="numpy"):
"""Evaluate QASM with Quimb
backend (quimb): numpy, cupy, jax. Passed to ``opt_einsum``.
"""
circuit = QiboCircuit.from_qasm(qasm)
init_state_mps = init_state_tn(circuit.nqubits, init_state)
circ_quimb = from_qibo(circuit, psi0=init_state_mps)
interim = circ_quimb.psi.full_simplify(seq="DRC")
amplitudes = interim.to_dense(backend=backend).flatten()
return amplitudes