cirq.quirk_url_to_circuit

Parses a Cirq circuit out of a Quirk URL.

cirq.quirk_url_to_circuit(
    quirk_url: str,
    *,
    qubits: Optional[Sequence['cirq.Qid']] = None,
    extra_cell_makers: Union[Dict[str, 'cirq.Gate'], Iterable['cirq.interop.quirk.cells.CellMaker']] = (),
    max_operation_count: int = (10 ** 6)
) -> 'cirq.Circuit'

Used in the notebooks

Used in the tutorials

quirk_url The URL of a bookmarked Quirk circuit. It is not required that the domain be "algassert.com/quirk". The only important part of the URL is the fragment (the part after the #).
qubits Qubits to use in the circuit. The length of the list must be at least the number of qubits in the Quirk circuit (including unused qubits). The maximum number of qubits in a Quirk circuit is 16. This argument defaults to cirq.LineQubit.range(16) when not specified.
extra_cell_makers Non-standard Quirk cells to accept. This can be used to parse URLs that come from a modified version of Quirk that includes gates that Quirk doesn't define. This can be specified as either a list of cirq.interop.quirk.cells.CellMaker instances, or for more simple cases as a dictionary from a Quirk id string to a cirq Gate.
max_operation_count If the number of operations in the circuit would exceed this value, the method raises a ValueError instead of attempting to construct the circuit. This is important to specify for servers parsing unknown input, because Quirk's format allows for a billion laughs attack in the form of nested custom gates.

Examples:

print(cirq.quirk_url_to_circuit(
    'http://algassert.com/quirk#circuit={"cols":[["H"],["•","X"]]}'
))
0: ───H───@───
          │
1: ───────X───

print(cirq.quirk_url_to_circuit(
    'http://algassert.com/quirk#circuit={"cols":[["H"],["•","X"]]}',
    qubits=[cirq.NamedQubit('Alice'), cirq.NamedQubit('Bob')]
))
Alice: ───H───@───
              │
Bob: ─────────X───

print(cirq.quirk_url_to_circuit(
    'http://algassert.com/quirk#circuit={"cols":[["iswap"]]}',
    extra_cell_makers={'iswap': cirq.ISWAP}))
0: ───iSwap───
      │
1: ───iSwap───

print(cirq.quirk_url_to_circuit(
    'http://algassert.com/quirk#circuit={"cols":[["iswap"]]}',
    extra_cell_makers=[
        cirq.interop.quirk.cells.CellMaker(
            identifier='iswap',
            size=2,
            maker=lambda args: cirq.ISWAP(*args.qubits))
    ]))
0: ───iSwap───
      │
1: ───iSwap───

The parsed circuit.

ValueError Invalid circuit URL, or circuit would be larger than max_operations_count.