def _prepare_state(state, qubits):
c = Circuit()
for q, s in zip(qubits, state):
if s == '0':
pass
elif s == '1':
c.append(Gate('X', [q]))
elif s == '+':
c.append(Gate('H', [q]))
elif s == '-':
c.extend([Gate('X', [q]), Gate('H', [q])])
else:
raise ValueError(f"Unexpected token '{s}'")
return c
def remove_swap(circuit: Circuit) -> tuple[Circuit, dict[any, any]]:
"""
Iteratively remove SWAP's from circuit by actually swapping qubits.
The output map will have the form new_qubit -> old_qubit.
"""
# Initialize map
_qubits_map = {q: q for q in circuit.all_qubits()}
# Initialize circuit
_circ = Circuit()
# Get ideal SWAP
_SWAP = Gate('SWAP').matrix()
# For each gate in circuit ..
for gate in circuit:
# Check if gate is close to SWAP
if gate.n_qubits == 2 and gate.qubits and np.allclose(
gate.matrix(), _SWAP):
# If true, swap qubits
_q0 = next(k for k, v in _qubits_map.items() if v == gate.qubits[0])
_q1 = next(k for k, v in _qubits_map.items() if v == gate.qubits[1])
_qubits_map[_q0], _qubits_map[_q1] = _qubits_map[_q1], _qubits_map[
_q0]
# Otherwise, remap qubits and append
else:
# Get the right qubits
_qubits = [
next(k
for k, v in _qubits_map.items()
if v == q)
for q in gate.qubits
]
# Append to the new circuit
_circ.append(gate.on(_qubits))
# Return circuit and map
return _circ, _qubits_map
def expand_iswap(circuit: Circuit) -> Circuit:
"""
Expand ISWAP's by iteratively replacing with SWAP's, CZ's and Phases.
"""
from copy import deepcopy
# Get ideal iSWAP
_iSWAP = Gate('ISWAP').matrix()
# Initialize circuit
_circ = Circuit()
# For each gate in circuit ..
for gate in circuit:
# Check if gate is close to SWAP
if gate.n_qubits == 2 and gate.qubits and np.allclose(
gate.matrix(), _iSWAP):
# Get tags
_tags = gate.tags if gate.provides('tags') else {}
# Expand iSWAP
_ext = [
Gate('SWAP', qubits=gate.qubits, tags=_tags),
Gate('CZ', qubits=gate.qubits, tags=_tags),
Gate('P', qubits=[gate.qubits[0]], tags=_tags),
Gate('P', qubits=[gate.qubits[1]], tags=_tags),
]
# Append to circuit
_circ.extend(_ext if gate.power == 1 else (
g**-1 for g in reversed(_ext)))
# Otherwise, just append
else:
_circ.append(deepcopy(gate))
# Return circuit
return _circ
def from_qasm(qasm_string: str) -> Circuit:
"""
Convert a QASM circuit to `Circuit`.
Parameters
----------
qasm_string: str
QASM circuit to convert to `Circuit`.
Returns
-------
Circuit
QAMS circuit converted to `Circuit`.
Notes
-----
The QASM language used in HybridQ is compatible with the standard QASM.
However, HybridQ introduces few extensions, which are recognized by the
parser using ``#@`` at the beginning of the line (``#`` at the beginning of
the line represent a general comment in QASM). At the moment, the following
QAMS extensions are supported:
* **qubits**, used to store `qubits_map`,
* **power**, used to store the power of the gate,
* **tags**, used to store the tags associated to the gate,
* **U**, used to store the matrix reprentation of the gate if gate name is `MATRIX`
If `Gate.qubits` are not specified, a single `.` is used to represent the
missing qubits. If `Gate.params` are missing, parameters are just omitted.
Example
-------
>>> from hybridq.extras.qasm import from_qasm
>>> qasm_str = \"\"\"
>>> 1
>>> #@ qubits =
>>> #@ {
>>> #@ "0": "42"
>>> #@ }
>>> #@ tags =
>>> #@ {
>>> #@ "params": false,
>>> #@ "qubits": false
>>> #@ }
>>> rx .
>>> #@ tags =
>>> #@ {
>>> #@ "params": true,
>>> #@ "qubits": false
>>> #@ }
>>> ry . 1.23
>>> #@ tags =
>>> #@ {
>>> #@ "params": false,
>>> #@ "qubits": true
>>> #@ }
>>> #@ power = 1.23
>>> rz 0
>>> #@ U =
>>> #@ [
>>> #@ [
>>> #@ "0.7071067811865475",
>>> #@ "0.7071067811865475"
>>> #@ ],
>>> #@ [
>>> #@ "0.7071067811865475",
>>> #@ "-0.7071067811865475"
>>> #@ ]
>>> #@ ]
>>> matrix .
>>> \"\"\"
>>> from_qasm(qasm_str)
Circuit([
Gate(name=RX, tags={'params': False, 'qubits': False})
Gate(name=RY, params=[1.23], tags={'params': True, 'qubits': False})
Gate(name=RZ, qubits=[42], tags={'params': False, 'qubits': True})**1.23
Gate(name=MATRIX, U=np.array(shape=(2, 2), dtype=float64))
])
"""
# Initialize circuit
circuit = Circuit()
# Initialize tags
_extra = None
_power = None
_conj = False
_T = False
_tags = None
_qubits_map = None
_U = None
for line in (line for line in qasm_string.split('\n')
if line and (line[0] != '#' or line[:2] == '#@')):
if line[:2] == '#@':
# Strip line
_line = re.sub(r'\s+', '', line)
if '#@tags=' in _line:
if _tags is not None:
raise ValueError('Format error.')
# Initialize tags
_tags = line.split('=')[-1]
_extra = 'tags'
elif '#@U=' in _line:
if _U is not None:
raise ValueError('Format error.')
# Initialize matrix
_U = line.split('=')[-1]
_extra = 'U'
elif '#@power=' in _line:
if _power is not None:
raise ValueError('Format error.')
# Initialize power
_power = line.split('=')[-1]
_extra = 'power'
elif '#@conj' in _line:
if _conj is not False:
raise ValueError('Format error.')
# Initialize conjugation
_conj = True
elif '#@T' in _line:
if _T is not False:
raise ValueError('Format error.')
# Initialize transposition
_T = True
elif '#@qubits=' in _line:
if _qubits_map is not None:
raise ValueError('Format error.')
# Initialize qubits
_qubits_map = line.split('=')[-1]
_extra = 'qubits'
elif _extra:
# Update tags
if _extra == 'tags':
_tags += line.replace('#@', '')
# Update matrix
elif _extra == 'U':
_U += line.replace('#@', '')
# Update power
elif _extra == 'power':
_power += line.replace('#@', '')
# Update qubits_map
elif _extra == 'qubits':
_qubits_map += line.replace('#@', '')
# Otherwise, error
else:
raise ValueError('Format error.')
else:
# Restart _extra
_extra = None
# Strip everything after the first #
line = line.split('#')[0].split()
# Make few guesses about format
if len(line) == 1:
if _isint(line[0]):
warn(
f"Skipping '{' '.join(line)}' (most likely the number of qubits in the circuit)."
)
continue
else:
warn(
f"Skipping '{' '.join(line)}' (format is not understood)."
)
continue
# Make few guesses about format
if _isint(line[0]):
warn(
f"Skipping {line[0]} in '{' '.join(line)}' (most likely the circuit layer)."
)
del (line[0])
# Make few guesses about format
if not _isstring(line[0]):
warn(
f"Skipping '{' '.join(line)}' (format is not understood).")
continue
if line[0].upper() == 'MATRIX':
# Remove name from line
del (line[0])
# Add tags
if not _U:
raise ValueError('Format error.')
# Set gate
_U = np.real_if_close(
np.array([[complex(y) for y in x]
for x in json.loads(_U)]))
gate = Gate('MATRIX', U=_U)
# Set qubits if present
if line[0] != '.':
# Set qubits
gate.on([int(x) for x in line], inplace=True)
# Reset
_U = None
else:
# Set position
_p = 0
# Initialize gate with name
gate = Gate(line[_p])
# Check if qubits are provided
_p += 1
if line[_p] != '.':
# Set qubits
gate.on([int(x) for x in line[_p:_p + gate.n_qubits]],
inplace=True)
_p += gate.n_qubits
else:
# Skip qubits
_p += 1
if _p != len(line):
if not gate.provides('params') and (
_p + gate.n_params) != len(line):
raise ValueError('Format error.')
gate.set_params(
[float(x) for x in line[_p:_p + gate.n_params]],
inplace=True)
_p += gate.n_params
if len(line) != _p:
print(line, gate)
# Add tags
if _tags:
gate._set_tags(json.loads(_tags))
# Apply power
if _power:
gate._set_power(float(_power))
# Add conjugation
if _conj:
gate._conj()
# Add transposition
if _T:
gate._T()
# Append gate to circuit
circuit.append(gate)
# Reset
_tags = None
# Reset power
_power = None
# Reset conjugation
_conj = False
# Reset transposition
_T = False
# Remap qubits
if _qubits_map is not None:
def _int(x):
try:
return int(x)
except:
return x
_qubits_map = json.loads(_qubits_map)
_qubits_map = {int(x): _int(y) for x, y in _qubits_map.items()}
for gate in circuit:
if gate.provides('qubits') and gate.qubits is not None:
gate._on([_qubits_map[x] for x in gate.qubits])
return circuit