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relocate code examples
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@abbycross
abbycross committed Nov 18, 2024
1 parent 659c627 commit 6c0f207
Showing 1 changed file with 165 additions and 140 deletions.
305 changes: 165 additions & 140 deletions qiskit/circuit/quantumcircuit.py
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Original file line number Diff line number Diff line change
Expand Up @@ -216,96 +216,18 @@ class QuantumCircuit:
.. autoattribute:: data
Example:
.. plot::
:include-source:
:nofigs:
from qiskit import QuantumCircuit
qc = QuantumCircuit(2, 2)
qc.measure([0], [1])
print(qc.data)
.. code-block:: text
[CircuitInstruction(operation=Instruction(name='measure', num_qubits=1,
num_clbits=1, params=[]), qubits=(Qubit(QuantumRegister(2, 'q'), 0),),
clbits=(Clbit(ClassicalRegister(2, 'c'), 1),))]
Alongside the :attr:`data`, the :attr:`global_phase` of a circuit can have some impact on its
output, if the circuit is used to describe a :class:`.Gate` that may be controlled. This is
measured in radians and is directly settable.
.. autoattribute:: global_phase
Example:
.. plot::
:include-source:
:nofigs:
:context: reset
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
qreg_q = QuantumRegister(2, 'q')
creg_c = ClassicalRegister(2, 'c')
circuit = QuantumCircuit(qreg_q, creg_c)
circuit.h(qreg_q[0])
circuit.cx(qreg_q[0], qreg_q[1])
print(circuit.global_phase) # find the global phase of the current circuit
.. code-block:: text
0.0
.. plot::
:include-source:
:nofigs:
:context:
from numpy import pi
circuit.global_phase = pi/4 # set the global phase of the circuit to pi/4
print(circuit.global_phase)
.. code-block:: text
0.7853981633974483
The :attr:`name` of a circuit becomes the name of the :class:`~.circuit.Instruction` or
:class:`.Gate` resulting from :meth:`to_instruction` and :meth:`to_gate` calls, which can be
handy for visualizations.
.. autoattribute:: name
Example:
.. plot::
:include-source:
:nofigs:
:context: reset
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
qr = QuantumRegister(2)
cr = ClassicalRegister(2)
qc = QuantumCircuit(qr, cr)
qc.h(qr[0])
qc.cx(qr[0], qr[1])
qc.measure(qr, cr)
qc.name = "my_circuit"
print(qc.name)
.. code-block:: text
my_circuit
You can attach arbitrary :attr:`metadata` to a circuit. No part of core Qiskit will inspect
this or change its behavior based on metadata, but it will be faithfully passed through the
transpiler, so you can tag your circuits yourself. When serializing a circuit with QPY (see
Expand All @@ -315,26 +237,6 @@ class QuantumCircuit:
.. autoattribute:: metadata
Example:
.. plot::
:include-source:
:nofigs:
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
q = QuantumRegister(2)
c = ClassicalRegister(2)
qc = QuantumCircuit(q, c)
qc.metadata = {'experiment_type': 'Bell state experiment'}
print(qc.metadata)
.. code-block:: text
{'experiment_type': 'Bell state experiment'}
:class:`QuantumCircuit` exposes data attributes tracking its internal quantum and classical bits
and registers. These appear as Python :class:`list`\\ s, but you should treat them as
immutable; changing them will *at best* have no effect, and more likely will simply corrupt
Expand All @@ -346,41 +248,6 @@ class QuantumCircuit:
.. autoattribute:: ancillas
.. autoattribute:: clbits
Example:
.. plot::
:include-source:
:nofigs:
:context: reset
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
qr1 = QuantumRegister(2)
qr2 = QuantumRegister(1)
cr1 = ClassicalRegister(2)
cr2 = ClassicalRegister(1)
qc = QuantumCircuit(qr1, qr2, cr1, cr2)
print("List the quantum registers:", qc.qregs)
print("List the classical registers:", qc.cregs)
print("List the qubits in this circuit:", qc.qubits)
print("List the ancilla qubits:", qc.ancillas)
print("List the classical bits in this circuit:", qc.clbits)
.. code-block:: text
List the quantum registers: [QuantumRegister(2, 'q0'),
QuantumRegister(1, 'q1')]
List the classical registers: [ClassicalRegister(2, 'c0'),
ClassicalRegister(1, 'c1')]
List the qubits in this circuit: [Qubit(QuantumRegister(2,
'q0'), 0), Qubit(QuantumRegister(2, 'q0'), 1), Qubit
(QuantumRegister(1, 'q1'), 0)]
List the ancilla qubits: []
List the classical bits in this circuit: [Clbit
(ClassicalRegister(2, 'c0'), 0), Clbit(ClassicalRegister(2,
'c0'), 1), Clbit(ClassicalRegister(1, 'c1'), 0)]
The :ref:`compile-time parameters <circuit-compile-time-parameters>` present in instructions on
the circuit are available in :attr:`parameters`. This has a canonical order (mostly lexical,
except in the case of :class:`.ParameterVector`), which matches the order that parameters will
Expand Down Expand Up @@ -1240,7 +1107,32 @@ def __init__(
regs = tuple(int(reg) for reg in regs) # cast to int
self._base_name = None
self.name: str
"""A human-readable name for the circuit."""
"""A human-readable name for the circuit.
Example:
.. plot::
:include-source:
:nofigs:
:context: reset
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
qr = QuantumRegister(2)
cr = ClassicalRegister(2)
qc = QuantumCircuit(qr, cr)
qc.h(qr[0])
qc.cx(qr[0], qr[1])
qc.measure(qr, cr)
qc.name = "my_circuit"
print(qc.name)
.. code-block:: text
my_circuit
"""
if name is None:
self._base_name = self._cls_prefix()
self._name_update()
Expand Down Expand Up @@ -1314,7 +1206,28 @@ def __init__(
"""Arbitrary user-defined dictionary of metadata for the circuit.
Qiskit will not examine the content of this mapping, but it will pass it through the
transpiler and reattach it to the output, so you can track your own metadata."""
transpiler and reattach it to the output, so you can track your own metadata.
Example:
.. plot::
:include-source:
:nofigs:
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
q = QuantumRegister(2)
c = ClassicalRegister(2)
qc = QuantumCircuit(q, c)
qc.metadata = {'experiment_type': 'Bell state experiment'}
print(qc.metadata)
.. code-block:: text
{'experiment_type': 'Bell state experiment'}
"""

@property
@deprecate_func(since="1.3.0", removal_timeline="in Qiskit 2.0.0", is_property=True)
Expand Down Expand Up @@ -1446,9 +1359,27 @@ def layout(self) -> Optional[TranspileLayout]:
def data(self) -> QuantumCircuitData:
"""The circuit data (instructions and context).
Returns:
QuantumCircuitData: a list-like object containing the :class:`.CircuitInstruction`\\ s
for each instruction.
Example:
.. plot::
:include-source:
:nofigs:
from qiskit import QuantumCircuit
qc = QuantumCircuit(2, 2)
qc.measure([0], [1])
print(qc.data)
.. code-block:: text
[CircuitInstruction(operation=Instruction(name='measure', num_qubits=1,
num_clbits=1, params=[]), qubits=(Qubit(QuantumRegister(2, 'q'), 0),),
clbits=(Clbit(ClassicalRegister(2, 'c'), 1),))]
Returns:
QuantumCircuitData: a list-like object containing the :class:`.CircuitInstruction`\\ s
for each instruction.
"""
return QuantumCircuitData(self)

Expand Down Expand Up @@ -1574,6 +1505,26 @@ def metadata(self) -> dict:
all transforms of the circuit (i.e., transpilation) and that providers will
associate any circuit metadata with the results it returns from
execution of that circuit.
Example:
.. plot::
:include-source:
:nofigs:
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
q = QuantumRegister(2)
c = ClassicalRegister(2)
qc = QuantumCircuit(q, c)
qc.metadata = {'experiment_type': 'Bell state experiment'}
print(qc.metadata)
.. code-block:: text
{'experiment_type': 'Bell state experiment'}
"""
return self._metadata

Expand Down Expand Up @@ -2406,7 +2357,43 @@ def qubits(self) -> list[Qubit]:
@property
def clbits(self) -> list[Clbit]:
"""A list of :class:`Clbit`\\ s in the order that they were added. You should not mutate
this."""
this.
Example:
.. plot::
:include-source:
:nofigs:
:context: reset
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
qr1 = QuantumRegister(2)
qr2 = QuantumRegister(1)
cr1 = ClassicalRegister(2)
cr2 = ClassicalRegister(1)
qc = QuantumCircuit(qr1, qr2, cr1, cr2)
print("List the quantum registers:", qc.qregs)
print("List the classical registers:", qc.cregs)
print("List the qubits in this circuit:", qc.qubits)
print("List the ancilla qubits:", qc.ancillas)
print("List the classical bits in this circuit:", qc.clbits)
.. code-block:: text
List the quantum registers: [QuantumRegister(2, 'q0'),
QuantumRegister(1, 'q1')]
List the classical registers: [ClassicalRegister(2, 'c0'),
ClassicalRegister(1, 'c1')]
List the qubits in this circuit: [Qubit(QuantumRegister(2,
'q0'), 0), Qubit(QuantumRegister(2, 'q0'), 1), Qubit
(QuantumRegister(1, 'q1'), 0)]
List the ancilla qubits: []
List the classical bits in this circuit: [Clbit
(ClassicalRegister(2, 'c0'), 0), Clbit(ClassicalRegister(2,
'c0'), 1), Clbit(ClassicalRegister(1, 'c1'), 0)]
"""
return self._data.clbits

@property
Expand Down Expand Up @@ -4292,7 +4279,45 @@ def from_qasm_str(qasm_str: str) -> "QuantumCircuit":

@property
def global_phase(self) -> ParameterValueType:
"""The global phase of the current circuit scope in radians."""
"""The global phase of the current circuit scope in radians.
Example:
.. plot::
:include-source:
:nofigs:
:context: reset
from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
qreg_q = QuantumRegister(2, 'q')
creg_c = ClassicalRegister(2, 'c')
circuit = QuantumCircuit(qreg_q, creg_c)
circuit.h(qreg_q[0])
circuit.cx(qreg_q[0], qreg_q[1])
print(circuit.global_phase) # find the global phase of the current circuit
.. code-block:: text
0.0
.. plot::
:include-source:
:nofigs:
:context:
from numpy import pi
circuit.global_phase = pi/4 # set the global phase of the circuit to pi/4
print(circuit.global_phase)
.. code-block:: text
0.7853981633974483
"""

if self._control_flow_scopes:
return self._control_flow_scopes[-1].global_phase
return self._data.global_phase
Expand Down

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