def StronglyEntanglingLayer(weights, wires, r=1, imprimitive=CNOT):
r"""A layer applying rotations on each qubit followed by cascades of 2-qubit entangling gates.
The 2-qubit or imprimitive gates act on each qubit :math:`i` chronologically. The second qubit for
each gate is determined by :math:`(i+r)\mod n`, where :math:`n` is equal to `len(wires)`
and :math:`range` a layer hyperparameter called the range.
This is an example of two 4-qubit strongly entangling layers (ranges :math:`r=1` and :math:`r=2`, respectively) with
rotations :math:`R` and CNOTs as imprimitives:
.. figure:: ../../_static/layer_sec.png
:align: center
:width: 60%
:target: javascript:void(0);
Args:
weights (array[float]): array of weights of shape ``(len(wires), 3)``
wires (Sequence[int]): sequence of qubit indices that the template acts on
Keyword Args:
r (int): range of the imprimitive gates of this layer, defaults to 1
imprimitive (pennylane.ops.Operation): two-qubit gate to use, defaults to :class:`~.CNOT`
"""
if len(wires) < 2:
raise ValueError(
"StronglyEntanglingLayer requires at least two wires or subsystems to apply "
"the imprimitive gates.")
for i, wire in enumerate(wires):
Rot(weights[i, 0], weights[i, 1], weights[i, 2], wires=wire)
num_wires = len(wires)
for i in range(num_wires):
imprimitive(wires=[wires[i], wires[(i + r) % num_wires]])
def StronglyEntanglingCircuitBlock(weights,
periodic=True,
r=1,
imprimitive=CNOT,
wires=None):
"""pennylane.template.StronglyEntanglingCircuitBlock(weights, periodic=True, r=1, imprimitive=qml.CNOT, wires)
An individual block of a strongly entangling circuit.
Args:
weights (array[float]): shape ``(len(wires), 3)`` array of weights
periodic (bool): whether to use periodic boundary conditions when
applying imprimitive gates
r (Sequence[int]): range of the imprimitive gates of this block
imprimitive (pennylane.ops.Operation): Imprimitive gate to use,
defaults to :class:`~.CNOT`
Keyword Args:
wires (Sequence[int]): Wires the block should act on
"""
for i, wire in enumerate(wires):
Rot(weights[i, 0], weights[i, 1], weights[i, 2], wires=wire)
num_wires = len(wires)
for i in range(num_wires) if periodic else range(num_wires - 1):
imprimitive(wires=[wires[i], wires[(i + r) % num_wires]])
def _strongly_entangling_layer(weights, wires, r, imprimitive):
r"""A layer applying rotations on each qubit followed by cascades of 2-qubit entangling gates.
Args:
weights (array[float]): array of weights of shape ``(len(wires), 3)``
wires (Sequence[int]): sequence of qubit indices that the template acts on
r (int): range of the imprimitive gates of this layer, defaults to 1
imprimitive (pennylane.ops.Operation): two-qubit gate to use, defaults to :class:`~pennylane.ops.CNOT`
"""
for i, wire in enumerate(wires):
Rot(weights[i, 0], weights[i, 1], weights[i, 2], wires=wire)
n_wires = len(wires)
if n_wires > 1:
for i in range(n_wires):
imprimitive(wires=[wires[i], wires[(i + r) % n_wires]])