from collections import defaultdict
from collections.abc import Mapping, Sequence
from functools import partial
from itertools import count, product
from ...log_gates.rot_surface_code_css import (
set_encoding,
set_fold_trans_s,
set_idle,
set_trans_cnot,
set_trans_cnot_mid_cycle_css,
set_x,
set_z,
)
from ..layout import Layout, QubitDict
from .util import check_distance, invert_shift, is_valid, set_missing_neighbours_to_none
DEFAULT_INTERACTION_ORDER = dict(
z_type=["north_west", "north_east", "south_west", "south_east"],
x_type=["north_west", "south_west", "north_east", "south_east"],
)
def get_data_index(col: int, row: int, row_size: int, start_ind: int = 1) -> int:
"""Converts row and column to data qubit index.
The data qubits are numbered starting from the bottom-left data qubit,
and increasing the index by 1 on the horizontal direction.
Assumes the initial index is 1 (as opposed to 0).
Parameters
----------
col
The column of the data qubit.
row
The row of the data qubit.
row_size
Row size of the code.
start_ind
The starting index for the data qubits, by default 1.
Returns
-------
int
The index of the data qubit.
"""
row_ind = row // 2
col_ind = col // 2
index = start_ind + (col_ind * row_size) + row_ind
return index
def shift_direction(col_shift: int, row_shift: int) -> str:
"""Translates a row and column shift to a direction.
Parameters
----------
col_shift
The column shift.
row_shift
The row shift.
Returns
-------
str
The direction.
"""
ver_direction = "north" if row_shift > 0 else "south"
hor_direction = "east" if col_shift > 0 else "west"
direction = f"{ver_direction}_{hor_direction}"
return direction
[docs]
def rot_surface_code_rectangle(
distance_x: int,
distance_z: int,
logical_qubit_label: str = "L0",
init_point: tuple[int | float, int | float] = (1, 1),
init_data_qubit_id: int = 1,
init_zanc_qubit_id: int = 1,
init_xanc_qubit_id: int = 1,
init_ind: int = 0,
init_logical_ind: int = 0,
interaction_order: Mapping[str, Sequence[str]] = DEFAULT_INTERACTION_ORDER,
) -> Layout:
"""Generates a rotated surface code layout.
Parameters
----------
distance_x
The logical X distance of the code.
distance_z
The logical Z distance of the code.
logical_qubit_label
Label for the logical qubit, by default ``"L0"``.
init_point
Coordinates for the bottom left (i.e. southest west) data qubit.
By default ``(1, 1)``.
init_data_qubit_id
Index for the bottom left (i.e. southest west) data qubit.
By default ``1``, so the label is ``"D1"``.
init_zanc_qubit_id
Index for the bottom left (i.e. southest west) Z-type ancilla qubit.
By default ``1``, so the label is ``"Z1"``.
init_xanc_qubit_id
Index for the bottom left (i.e. southest west) X-type ancilla qubit.
By default ``1``, so the label is ``"X1"``.
init_ind
Minimum index that is going to be associated to a qubit.
init_logical_ind
Minimum index that is going to be associated to a logical qubit.
interaction_order
Dictionary specifying the interaction order for the ``x_type`` and
``z_type`` stabilizers. The possible interaction directions are:
``"north_east"``, ``"north_west"``, ``"south_east"``, and ``"south_west"``.
Returns
-------
Layout
The layout of the code.
"""
check_distance(distance_x)
check_distance(distance_z)
if not isinstance(init_point, tuple):
raise TypeError(
f"'init_point' must be a tuple, but {type(init_point)} was given."
)
if (len(init_point) != 2) or any(
not isinstance(p, (float, int)) for p in init_point
):
raise TypeError("'init_point' must have two elements that are floats or ints.")
if not isinstance(logical_qubit_label, str):
raise TypeError(
"'logical_qubit_label' must be a string, "
f"but {type(logical_qubit_label)} was given."
)
if not isinstance(init_data_qubit_id, int):
raise TypeError(
"'init_data_qubit_id' must be an int, "
f"but {type(init_data_qubit_id)} was given."
)
if not isinstance(init_zanc_qubit_id, int):
raise TypeError(
"'init_zanc_qubit_id' must be an int, "
f"but {type(init_zanc_qubit_id)} was given."
)
if not isinstance(init_xanc_qubit_id, int):
raise TypeError(
"'init_xanc_qubit_id' must be an int, "
f"but {type(init_xanc_qubit_id)} was given."
)
name = f"Rotated dx-{distance_x} dz-{distance_z} surface code layout."
code = "rotated_surface_code"
description = ""
log_z = [f"D{i + init_data_qubit_id}" for i in range(distance_z)]
log_x = [f"D{i * distance_z + init_data_qubit_id}" for i in range(distance_x)]
logical_qubits = {
logical_qubit_label: dict(log_x=log_x, log_z=log_z, ind=init_logical_ind)
}
layout_setup = dict(
name=name,
code=code,
logical_qubits=logical_qubits,
description=description,
distance_x=distance_x,
distance_z=distance_z,
interaction_order=interaction_order,
)
if distance_x == distance_z:
layout_setup["distance"] = distance_z
col_size = 2 * distance_x + 1
row_size = 2 * distance_z + 1
data_indexer = partial(
get_data_index, row_size=distance_z, start_ind=init_data_qubit_id
)
valid_coord = partial(is_valid, max_size_col=col_size, max_size_row=row_size)
pos_shifts = (1, -1)
nbr_shifts = tuple(product(pos_shifts, repeat=2))
layout_data: list[QubitDict] = []
neighbor_data: defaultdict[str, dict[str, str | None]] = defaultdict(dict)
ind = init_ind
# change initial point because by default the code places the "D1" qubit
# in the (1,1) point.
init_point = (init_point[0] - 1, init_point[1] - 1)
for col in range(1, col_size, 2):
for row in range(1, row_size, 2):
index = data_indexer(col, row)
qubit_info = dict(
qubit=f"D{index}",
role="data",
coords=[col + init_point[0], row + init_point[1]],
stab_type=None,
ind=ind,
)
layout_data.append(qubit_info)
ind += 1
x_index = count(start=init_xanc_qubit_id)
for col in range(0, col_size, 2):
for row in range(2 + col % 4, row_size - 1, 4):
anc_qubit = f"X{next(x_index)}"
qubit_info = dict(
qubit=anc_qubit,
role="anc",
coords=[col + init_point[0], row + init_point[1]],
stab_type="x_type",
ind=ind,
)
layout_data.append(qubit_info)
ind += 1
for col_shift, row_shift in nbr_shifts:
data_row, data_col = row + row_shift, col + col_shift
if not valid_coord(data_col, data_row):
continue
data_index = data_indexer(data_col, data_row)
data_qubit = f"D{data_index}"
direction = shift_direction(col_shift, row_shift)
neighbor_data[anc_qubit][direction] = data_qubit
inv_shifts = invert_shift(col_shift, row_shift)
inv_direction = shift_direction(*inv_shifts)
neighbor_data[data_qubit][inv_direction] = anc_qubit
z_index = count(start=init_zanc_qubit_id)
for col in range(2, col_size - 1, 2):
for row in range(col % 4, row_size, 4):
anc_qubit = f"Z{next(z_index)}"
qubit_info = dict(
qubit=anc_qubit,
role="anc",
coords=[col + init_point[0], row + init_point[1]],
stab_type="z_type",
ind=ind,
)
layout_data.append(qubit_info)
ind += 1
for col_shift, row_shift in nbr_shifts:
data_row, data_col = row + row_shift, col + col_shift
if not valid_coord(data_col, data_row):
continue
data_index = data_indexer(data_col, data_row)
data_qubit = f"D{data_index}"
direction = shift_direction(col_shift, row_shift)
neighbor_data[anc_qubit][direction] = data_qubit
inv_shifts = invert_shift(col_shift, row_shift)
inv_direction = shift_direction(*inv_shifts)
neighbor_data[data_qubit][inv_direction] = anc_qubit
set_missing_neighbours_to_none(neighbor_data)
for qubit_info in layout_data:
qubit = qubit_info["qubit"]
qubit_info["neighbors"] = neighbor_data[qubit]
layout_setup["layout"] = layout_data
layout = Layout(layout_setup)
return layout
[docs]
def rot_surface_code(
distance: int,
logical_qubit_label: str = "L0",
init_point: tuple[int | float, int | float] = (1, 1),
init_data_qubit_id: int = 1,
init_zanc_qubit_id: int = 1,
init_xanc_qubit_id: int = 1,
init_ind: int = 0,
init_logical_ind: int = 0,
interaction_order: Mapping[str, Sequence[str]] = DEFAULT_INTERACTION_ORDER,
) -> Layout:
"""Generates a rotated surface code layout.
Parameters
----------
distance
The distance of the code.
logical_qubit_label
Label for the logical qubit, by default ``"L0"``.
init_point
Coordinates for the bottom left (i.e. southest west) data qubit.
By default ``1``, so the label is ``"D1"``.
init_data_qubit_id
Index for the bottom left (i.e. southest west) data qubit.
By default ``1``, so the label is ``"D1"``.
init_zanc_qubit_id
Index for the bottom left (i.e. southest west) Z-type ancilla qubit.
By default ``1``, so the label is ``"Z1"``.
init_xanc_qubit_id
Index for the bottom left (i.e. southest west) X-type ancilla qubit.
By default ``1``, so the label is ``"X1"``.
init_ind
Minimum index that is going to be associated to a qubit.
init_logical_ind
Minimum index that is going to be associated to a logical qubit.
interaction_order
Dictionary specifying the interaction order for the ``x_type`` and
``z_type`` stabilizers. The possible interaction directions are:
``"north_east"``, ``"north_west"``, ``"south_east"``, and ``"south_west"``.
Returns
-------
Layout
The layout of the code.
"""
return rot_surface_code_rectangle(
distance_x=distance,
distance_z=distance,
logical_qubit_label=logical_qubit_label,
init_point=init_point,
init_data_qubit_id=init_data_qubit_id,
init_zanc_qubit_id=init_zanc_qubit_id,
init_xanc_qubit_id=init_xanc_qubit_id,
init_ind=init_ind,
init_logical_ind=init_logical_ind,
interaction_order=interaction_order,
)
[docs]
def rot_surface_codes(num_layouts: int, distance: int) -> list[Layout]:
"""
Returns a list of (square) rotated surface codes of the specified distance that
are set up to be used in any logical circuit (i.e. they have all the
implemented logical gate attributes).
Parameters
----------
num_layouts
Number of layouts to generate.
distance
The code distance.
Returns
-------
layouts
List of layouts.
"""
if not isinstance(num_layouts, int):
raise TypeError(
f"'num_layouts' must be an int, but {type(num_layouts)} was given."
)
layouts: list[Layout] = []
num_data = distance**2
num_anc = num_data - 1
for k in range(num_layouts):
layout = rot_surface_code(
distance=distance,
logical_qubit_label=f"L{k}",
init_point=(0, (2 * distance + 2) * k),
init_data_qubit_id=1 + k * num_data,
init_zanc_qubit_id=1 + k * num_anc // 2,
init_xanc_qubit_id=1 + k * num_anc // 2,
init_ind=k * (num_data + num_anc),
init_logical_ind=k,
)
layouts.append(layout)
# set up the parameters for all the logical gates
for k, layout in enumerate(layouts):
set_x(layout)
set_z(layout)
set_idle(layout)
set_encoding(layout)
for other_layout in layouts:
if layout == other_layout:
continue
set_trans_cnot(layout, other_layout)
set_trans_cnot_mid_cycle_css(layout, other_layout)
return layouts
[docs]
def rot_surface_code_rectangles(num_layouts: int, distance: int) -> list[Layout]:
"""
Returns a list of rotated surface codes of the specified distance that
are set up to be used in any logical circuit (i.e. they have all the
implemented logical gate attributes).
Parameters
----------
num_layouts
Number of layouts to generate.
distance
The distance of logical Pauli X of the layouts. The distance of logical
Pauli Z is ``distance + 1``.
Returns
-------
layouts
List of layouts.
"""
if not isinstance(num_layouts, int):
raise TypeError(
f"'num_layouts' must be an int, but {type(num_layouts)} was given."
)
layouts: list[Layout] = []
num_data = (distance + 1) * distance
num_anc = num_data - 1
for k in range(num_layouts):
layout = rot_surface_code_rectangle(
distance_x=distance,
distance_z=distance + 1,
logical_qubit_label=f"L{k}",
init_point=(0, (2 * distance + 4) * k),
init_data_qubit_id=1 + k * num_data,
init_zanc_qubit_id=1 + k * num_anc // 2,
init_xanc_qubit_id=1 + k * (num_anc // 2 + 1),
init_ind=k * (num_data + num_anc),
init_logical_ind=k,
)
layouts.append(layout)
# set up the parameters for all the logical gates
for k, layout in enumerate(layouts):
set_fold_trans_s(layout, data_qubit=f"D{1 + k * num_data}")
set_x(layout)
set_z(layout)
set_idle(layout)
for other_layout in layouts:
if layout == other_layout:
continue
set_trans_cnot(layout, other_layout)
return layouts
[docs]
def rot_surface_stability_rectangle(
stab_type: str,
width: int,
height: int,
observable: str = "O0",
init_point: tuple[int | float, int | float] = (1, 1),
init_data_qubit_id: int = 1,
init_zanc_qubit_id: int = 1,
init_xanc_qubit_id: int = 1,
init_ind: int = 0,
interaction_order: Mapping[str, Sequence[str]] = DEFAULT_INTERACTION_ORDER,
) -> Layout:
"""
Generates a rotated surface layout for stability experiments.
Parameters
----------
stab_type
Type of the stabilizer that lead to the identity when multiplying all
stabilizers of that type. It must be ``"x_type"`` or ``"z_type"``.
width
Width of the rotated_surface code layout in terms of the number
of data qubit along the horizontal dimension.
height
Heigh of the rotated_surface code layout in terms of the number
of data qubit along the vertical dimension.
observable
Label for the observable, by default ``"L0"``.
init_point
Coordinates for the bottom left (i.e. southest west) data qubit.
By default ``(1, 1)``.
init_data_qubit_id
Index for the bottom left (i.e. southest west) data qubit.
By default ``1``, so the label is ``"D1"``.
init_zanc_qubit_id
Index for the bottom left (i.e. southest west) Z-type ancilla qubit.
By default ``1``, so the label is ``"Z1"``.
init_xanc_qubit_id
Index for the bottom left (i.e. southest west) X-type ancilla qubit.
By default ``1``, so the label is ``"X1"``.
init_ind
Minimum index that is going to be associated to a qubit.
interaction_order
Dictionary specifying the interaction order for the ``x_type`` and
``z_type`` stabilizers. The possible interaction directions are:
``"north_east"``, ``"north_west"``, ``"south_east"``, and ``"south_west"``.
Returns
-------
Layout
The layout.
"""
check_distance(width)
check_distance(height)
if stab_type not in ("x_type", "z_type"):
raise ValueError(
f"'stab_type' must be 'x_type' or 'z_type', but {stab_type} was given."
)
if not isinstance(init_point, tuple):
raise TypeError(
f"'init_point' must be a tuple, but {type(init_point)} was given."
)
if (len(init_point) != 2) or any(
not isinstance(p, (float, int)) for p in init_point
):
raise TypeError("'init_point' must have two elements that are floats or ints.")
if not isinstance(observable, str):
raise TypeError(
f"'observable' must be a string, but {type(observable)} was given."
)
if not isinstance(init_data_qubit_id, int):
raise TypeError(
"'init_data_qubit_id' must be an int, "
f"but {type(init_data_qubit_id)} was given."
)
if not isinstance(init_zanc_qubit_id, int):
raise TypeError(
"'init_zanc_qubit_id' must be an int, "
f"but {type(init_zanc_qubit_id)} was given."
)
if not isinstance(init_xanc_qubit_id, int):
raise TypeError(
"'init_xanc_qubit_id' must be an int, "
f"but {type(init_xanc_qubit_id)} was given."
)
name = f"Rotated w-{width} h-{height} surface layout for stability experiments."
code = "rotated_surface_stability"
description = ""
col_size = 2 * width
row_size = 2 * height
data_indexer = partial(
get_data_index, row_size=height, start_ind=init_data_qubit_id
)
valid_coord = partial(is_valid, max_size_col=col_size, max_size_row=row_size)
pos_shifts = (1, -1)
nbr_shifts = tuple(product(pos_shifts, repeat=2))
layout_data: list[QubitDict] = []
neighbor_data: defaultdict[str, dict[str, str | None]] = defaultdict(dict)
ind = init_ind
# change initial point because by default the code places the "D1" qubit
# in the (1,1) point.
init_point = (init_point[0] - 1, init_point[1] - 1)
for row in range(1, row_size, 2):
for col in range(1, col_size, 2):
index = data_indexer(col, row)
qubit_info = dict(
qubit=f"D{index}",
role="data",
coords=[col + init_point[0], row + init_point[1]],
stab_type=None,
ind=ind,
)
layout_data.append(qubit_info)
ind += 1
if stab_type == "x_type":
init_sanc_qubit_id = init_xanc_qubit_id
init_oanc_qubit_id = init_zanc_qubit_id
other_stab_type = "z_type"
s, o = "X", "Z"
else:
init_sanc_qubit_id = init_zanc_qubit_id
init_oanc_qubit_id = init_xanc_qubit_id
other_stab_type = "x_type"
s, o = "Z", "X"
s_index = count(start=init_sanc_qubit_id)
for row in range(0, row_size + 1, 2):
for col in range((2 + row) % 4, col_size + 1, 4):
anc_qubit = f"{s}{next(s_index)}"
qubit_info = dict(
qubit=anc_qubit,
role="anc",
coords=[col + init_point[0], row + init_point[1]],
stab_type=stab_type,
ind=ind,
)
layout_data.append(qubit_info)
ind += 1
for col_shift, row_shift in nbr_shifts:
data_row, data_col = row + row_shift, col + col_shift
if not valid_coord(data_col, data_row):
continue
data_index = data_indexer(data_col, data_row)
data_qubit = f"D{data_index}"
direction = shift_direction(col_shift, row_shift)
neighbor_data[anc_qubit][direction] = data_qubit
inv_shifts = invert_shift(col_shift, row_shift)
inv_direction = shift_direction(*inv_shifts)
neighbor_data[data_qubit][inv_direction] = anc_qubit
o_index = count(start=init_oanc_qubit_id)
for row in range(2, row_size - 1, 2):
for col in range(2 + (2 + row) % 4, col_size, 4):
anc_qubit = f"{o}{next(o_index)}"
qubit_info = dict(
qubit=anc_qubit,
role="anc",
coords=[col + init_point[0], row + init_point[1]],
stab_type=other_stab_type,
ind=ind,
)
layout_data.append(qubit_info)
ind += 1
for col_shift, row_shift in nbr_shifts:
data_row, data_col = row + row_shift, col + col_shift
if not valid_coord(data_col, data_row):
continue
data_index = data_indexer(data_col, data_row)
data_qubit = f"D{data_index}"
direction = shift_direction(col_shift, row_shift)
neighbor_data[anc_qubit][direction] = data_qubit
inv_shifts = invert_shift(col_shift, row_shift)
inv_direction = shift_direction(*inv_shifts)
neighbor_data[data_qubit][inv_direction] = anc_qubit
set_missing_neighbours_to_none(neighbor_data)
anc_redundant_stab_type: list[str] = []
for qubit_info in layout_data:
qubit = qubit_info["qubit"]
qubit_info["neighbors"] = neighbor_data[qubit]
if qubit_info["role"] == "anc" and qubit_info["stab_type"] == stab_type:
anc_redundant_stab_type.append(qubit)
layout_setup = dict(
name=name,
code=code,
observables={observable: anc_redundant_stab_type},
description=description,
interaction_order=interaction_order,
)
layout_setup["layout"] = layout_data
layout = Layout(layout_setup)
return layout
