"""
\********************************************************************************
* Copyright (c) 2023 the Qrisp authors
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the Eclipse
* Public License, v. 2.0 are satisfied: GNU General Public License, version 2
* with the GNU Classpath Exception which is
* available at https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
********************************************************************************/
"""
import inspect
from qrisp.environments.quantum_environments import QuantumEnvironment
from qrisp.environments.gate_wrap_environment import GateWrapEnvironment
from qrisp.circuit import Operation, QuantumCircuit, Instruction
from qrisp.environments.iteration_environment import IterationEnvironment
from qrisp.core import merge
[docs]def custom_control(func):
"""
The ``custom_control`` decorator allows to specify the controlled version of
the decorated function. If this function is called within a :ref:`ControlEnvironment`
or a :ref:`ConditionEnvironment` the controlled version is executed instead.
Specific controlled versions of quantum functions are very common in many
scientific publications. This is because the general control procedure can
signifcantly increase resource demands.
In order to use the ``custom_control`` decorator, you need to add the ``ctrl``
keyword to your function signature. If called within a controlled context,
this keyword will receive the corresponding control qubit.
For more details consult the examples section.
Parameters
----------
func : function
A function of QuantumVariables, which has the ``ctrl`` keyword.
Returns
-------
adaptive_control_function : function
A function which will execute it's controlled version, if called
within a :ref:`ControlEnvironment` or a :ref:`ConditionEnvironment`.
Examples
--------
We create a swap function with custom control.
::
from qrisp import mcx, cx, custom_control
@custom_control
def swap(a, b, ctrl = None):
if ctrl is None:
cx(a, b)
cx(b, a)
cx(a, b)
else:
cx(a, b)
mcx([ctrl, b], a)
cx(a, b)
Test the non-controlled version:
::
from qrisp import QuantumBool
a = QuantumBool()
b = QuantumBool()
swap(a, b)
print(a.qs)
::
QuantumCircuit:
--------------
┌───┐
a.0: ──■──┤ X ├──■──
┌─┴─┐└─┬─┘┌─┴─┐
b.0: ┤ X ├──■──┤ X ├
└───┘ └───┘
Live QuantumVariables:
---------------------
QuantumBool a
QuantumBool b
Test the controlled version:
::
from qrisp import control
a = QuantumBool()
b = QuantumBool()
ctrl_qbl = QuantumBool()
with control(ctrl_qbl):
swap(a,b)
print(a.qs.transpile(1))
::
┌───┐
a.0: ──■──┤ X ├──■──
┌─┴─┐└─┬─┘┌─┴─┐
b.0: ┤ X ├──■──┤ X ├
└───┘ │ └───┘
ctrl_qbl.0: ───────■───────
"""
def adaptive_control_function(*args, **kwargs):
from qrisp.core import recursive_qs_search
from qrisp import merge, ControlEnvironment, ConditionEnvironment, QuantumEnvironment, InversionEnvironment, ConjugationEnvironment
qs_list = recursive_qs_search(args)
if "ctrl" in kwargs:
if kwargs["ctrl"] is not None:
qs_list.append(kwargs["ctrl"].qs())
merge(qs_list)
if len(qs_list) == 0:
return func(*args, **kwargs)
qs = qs_list[0]
# Search for a Control/Condition Environment and get the control qubit
control_qb = None
for env in qs.env_stack[::-1]:
if isinstance(env, (ControlEnvironment, ConditionEnvironment)):
control_qb = env.condition_truth_value
break
if not isinstance(env, (InversionEnvironment, ConjugationEnvironment, GateWrapEnvironment)):
if isinstance(env, IterationEnvironment):
if env.precompile:
break
else:
continue
break
# If no control qubit was found, simply execute the function
if control_qb is None:
return func(*args, **kwargs)
# Check whether the function supports the ctrl_method kwarg and adjust
# the kwargs accordingly
if "ctrl_method" in list(inspect.getfullargspec(func))[0] and isinstance(env, ControlEnvironment):
kwargs.update({"ctrl_method" : env.ctrl_method})
# In the case that a qubit was found, we use the CustomControlEnvironent (definded below)
# This environments gatewraps the function and compiles it to a specific Operation subtype
# called CustomControlledOperation.
# The Condition/Control Environment compiler recognizes this Operation type
# and processes it accordingly
with CustomControlEnvironment(control_qb, func.__name__):
if "ctrl" in kwargs:
kwargs["ctrl"] = control_qb
res = func(*args, **kwargs)
else:
res = func(*args, ctrl = control_qb, **kwargs)
return res
return adaptive_control_function
class CustomControlEnvironment(QuantumEnvironment):
def __init__(self, control_qb, name):
self.control_qb = control_qb
self.manual_allocation_management = True
def __enter__(self):
QuantumEnvironment.__enter__(self)
merge([self.env_qs, self.control_qb.qs()])
def compile(self):
original_data = list(self.env_qs.data)
self.env_qs.data = []
QuantumEnvironment.compile(self)
temp = list(self.env_qs.data)
self.env_qs.data = []
for instr in temp:
if instr.op.name in ["qb_alloc", "qb_dealloc"]:
self.env_qs.append(instr)
elif self.control_qb in instr.qubits:
cusc_op = CustomControlOperation(instr.op, targeting_control = True)
self.env_qs.append(cusc_op, instr.qubits, instr.clbits)
else:
cusc_op = CustomControlOperation(instr.op)
self.env_qs.append(cusc_op, [self.control_qb] + instr.qubits, instr.clbits)
self.env_qs.data = original_data + list(self.env_qs.data)
class CustomControlOperation(Operation):
def __init__(self, init_op, targeting_control = False):
self.targeting_control = targeting_control
if not targeting_control:
definition = QuantumCircuit(init_op.num_qubits + 1, init_op.num_clbits)
definition.data.append(Instruction(init_op, definition.qubits[1:], definition.clbits))
Operation.__init__(self, name = "cusc_" + init_op.name, num_qubits = init_op.num_qubits + 1, num_clbits = init_op.num_clbits, definition = definition)
self.init_op = init_op
self.permeability = {i+1 : init_op.permeability[i] for i in range(init_op.num_qubits)}
self.permeability[0] = True
self.is_qfree = init_op.is_qfree
else:
definition = QuantumCircuit(init_op.num_qubits, init_op.num_clbits)
definition.append(init_op, definition.qubits, definition.clbits)
Operation.__init__(self, name = "cusc_" + init_op.name, num_qubits = init_op.num_qubits, num_clbits = init_op.num_clbits, definition = definition)
self.init_op = init_op
self.permeability = dict(init_op.permeability)
self.is_qfree = bool(init_op.is_qfree)
def inverse(self):
temp = self.init_op.inverse()
return CustomControlOperation(temp, targeting_control = self.targeting_control)
def copy(self):
return CustomControlOperation(self.init_op.copy(), targeting_control = self.targeting_control)