Source code for qailab.circuit.encoding_blocks.amplitude

 1"""Blocks encoding values as initial state for a quantum circuit"""
 2from typing import Literal
 3from qiskit.circuit import QuantumCircuit, ParameterVector
 4from qiskit_machine_learning.circuit.library import RawFeatureVector
 5
 6from qailab.circuit.base import EncodingBlock, NonGateBlock
 7
 8

[docs]
 9class TypedRawFeatureVector(RawFeatureVector):
10    """Extension of RawFeatureVector that renames the parameters."""
11
12    def __init__(self, feature_dimension: int | None, block_type: Literal['input'] | Literal['weight'] = 'input') -> None:
13        super().__init__(feature_dimension)
14        self._ordered_parameters = ParameterVector(f"{block_type}_Amp_Encoder_Params_{hex(id(super()))}")

15
16

[docs]
17class AmplitudeEncoder(NonGateBlock, EncodingBlock):
18    """
19    Encode input as initial state of the circuit.
20    """
21
22    def __init__(self, block_type: Literal['input'] | Literal['weight'] = 'input') -> None:
23        super().__init__("AmplitudeEncoder", block_type)
24
25    def _build_circuit(self, num_qubits: int) -> QuantumCircuit:
26        circuit = TypedRawFeatureVector(2**num_qubits, self.block_type)
27        self._parameters = list(circuit.parameters)
28        return circuit