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general_decomposer

check_gate_decomposition 

check_gate_decomposition(
    gate: Gate, decomposition_gates: Iterable[Gate]
) -> None

Checks that the decomposition gate(s) are valid by verifying that they operate on the same qubits and preserve the quantum state up to a global phase.

Parameters:

Name Type Description Default
gate Gate

Gate that is being decomposed.

 required
decomposition_gates Iterable[Gate]

Gate(s) that are decomposing the original gate.

 required

Raises:

Type Description
ValueError

If the decomposition gates do not operate on the same qubits as the original gate.
ValueError

If the decomposition gates do not preserve the quantum state up to a global phase.
Source code in opensquirrel/passes/decomposer/general_decomposer.py 
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def check_gate_decomposition(gate: Gate, decomposition_gates: Iterable[Gate]) -> None:
    """Checks that the decomposition gate(s) are valid by verifying that they operate on the same
    qubits and preserve the quantum state up to a global phase.

    Args:
        gate (Gate): Gate that is being decomposed.
        decomposition_gates (Iterable[Gate]): Gate(s) that are decomposing the original gate.

    Raises:
        ValueError: If the decomposition gates do not operate on the same qubits as the original gate.
        ValueError: If the decomposition gates do not preserve the quantum state up to a global phase.

    """
    gate_qubit_indices = gate.qubit_indices
    decomposition_gates_qubit_indices = set()
    decomposed_matrix = get_circuit_matrix(get_reindexed_circuit([gate], gate_qubit_indices))

    if is_identity_matrix_up_to_a_global_phase(decomposed_matrix):
        return

    for decomposition_gate in decomposition_gates:
        decomposition_gates_qubit_indices.update(decomposition_gate.qubit_indices)

    if set(gate_qubit_indices) != decomposition_gates_qubit_indices:
        msg = f"decomposition for gate {gate.name!r} does not operate on the correct qubits"
        raise ValueError(msg)

    decomposition_matrix = get_circuit_matrix(get_reindexed_circuit(decomposition_gates, gate_qubit_indices))

    if not are_matrices_equivalent_up_to_global_phase(decomposed_matrix, decomposition_matrix):
        msg = f"decomposition for gate {gate.name!r} does not preserve the quantum state"
        raise ValueError(msg)

decompose 

decompose(ir: IR, decomposer: Decomposer) -> None

Decomposes the statements in the circuit IR using the provided decomposer.

Parameters:

Name Type Description Default
ir IR

The circuit IR to decompose.

 required
decomposer Decomposer

The decomposer to use for decomposing the gates.

 required
Source code in opensquirrel/passes/decomposer/general_decomposer.py 
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def decompose(ir: IR, decomposer: Decomposer) -> None:
    """Decomposes the statements in the circuit IR using the provided decomposer.

    Args:
        ir (IR): The circuit IR to decompose.
        decomposer (Decomposer): The decomposer to use for decomposing the gates.

    """
    statement_index = 0
    while statement_index < len(ir.statements):
        statement = ir.statements[statement_index]

        if isinstance(statement, Gate):
            gate = statement
            replacement_gates: list[Gate] = decomposer.decompose(statement)
            check_gate_decomposition(gate, replacement_gates)

            ir.statements[statement_index : statement_index + 1] = replacement_gates
            statement_index += len(replacement_gates)

        elif isinstance(statement, Measure):
            measure_decomposition = decomposer.decompose(statement)
            ir.statements[statement_index : statement_index + 1] = measure_decomposition
            statement_index += len(measure_decomposition)
        else:
            statement_index += 1