def _sample_measure_results(
self,
program: circuits.Circuit,
repetitions: int = 1,
) -> Dict[str, np.ndarray]:
"""Samples from measurement gates in the circuit.
Note that this will execute the circuit 'repetitions' times.
Args:
program: The circuit to sample from.
repetitions: The number of samples to take.
Returns:
A dictionary from measurement gate key to measurement
results. Measurement results are stored in a 2-dimensional
numpy array, the first dimension corresponding to the repetition
and the second to the actual boolean measurement results (ordered
by the qubits being measured.)
Raises:
ValueError: If there are multiple MeasurementGates with the same key,
or if repetitions is negative.
"""
if not isinstance(program, qsimc.QSimCircuit):
program = qsimc.QSimCircuit(program, device=program.device)
# Compute indices of measured qubits
ordered_qubits = ops.QubitOrder.DEFAULT.order_for(program.all_qubits())
num_qubits = len(ordered_qubits)
qubit_map = {
qubit: index
for index, qubit in enumerate(ordered_qubits)
}
# Computes
# - the list of qubits to be measured
# - the start (inclusive) and end (exclusive) indices of each measurement
# - a mapping from measurement key to measurement gate
measurement_ops = [
op for _, op, _ in program.findall_operations_with_gate_type(
ops.MeasurementGate)
]
measured_qubits = [] # type: List[ops.Qid]
bounds = {} # type: Dict[str, Tuple]
meas_ops = {} # type: Dict[str, cirq.GateOperation]
current_index = 0
for op in measurement_ops:
gate = op.gate
key = protocols.measurement_key(gate)
meas_ops[key] = op
if key in bounds:
raise ValueError(
"Duplicate MeasurementGate with key {}".format(key))
bounds[key] = (current_index, current_index + len(op.qubits))
measured_qubits.extend(op.qubits)
current_index += len(op.qubits)
# Set qsim options
options = {}
options.update(self.qsim_options)
results = {}
for key, bound in bounds.items():
results[key] = np.ndarray(shape=(repetitions, bound[1] - bound[0]),
dtype=int)
noisy = _needs_trajectories(program)
if noisy:
translator_fn_name = 'translate_cirq_to_qtrajectory'
sampler_fn = qsim.qtrajectory_sample
else:
translator_fn_name = 'translate_cirq_to_qsim'
sampler_fn = qsim.qsim_sample
if not noisy and program.are_all_measurements_terminal(
) and repetitions > 1:
print('Provided circuit has no intermediate measurements. ' +
'Sampling repeatedly from final state vector.')
# Measurements must be replaced with identity gates to sample properly.
# Simply removing them may omit qubits from the circuit.
for i in range(len(program.moments)):
program.moments[i] = ops.Moment(
op if not isinstance(op.gate, ops.MeasurementGate) else
[ops.IdentityGate(1).on(q) for q in op.qubits]
for op in program.moments[i])
options['c'] = program.translate_cirq_to_qsim(
ops.QubitOrder.DEFAULT)
options['s'] = self.get_seed()
final_state = qsim.qsim_simulate_fullstate(options, 0)
full_results = sim.sample_state_vector(final_state.view(
np.complex64),
range(num_qubits),
repetitions=repetitions,
seed=self._prng)
for i in range(repetitions):
for key, op in meas_ops.items():
meas_indices = [qubit_map[qubit] for qubit in op.qubits]
for j, q in enumerate(meas_indices):
results[key][i][j] = full_results[i][q]
else:
translator_fn = getattr(program, translator_fn_name)
options['c'] = translator_fn(ops.QubitOrder.DEFAULT)
for i in range(repetitions):
options['s'] = self.get_seed()
measurements = sampler_fn(options)
for key, bound in bounds.items():
for j in range(bound[1] - bound[0]):
results[key][i][j] = int(measurements[bound[0] + j])
return results
class QasmParser:
"""Parser for QASM strings.
Example:
qasm = "OPENQASM 2.0; qreg q1[2]; CX q1[0], q1[1];"
parsedQasm = QasmParser().parse(qasm)
"""
def __init__(self):
self.parser = yacc.yacc(module=self, debug=False, write_tables=False)
self.circuit = Circuit()
self.qregs: Dict[str, int] = {}
self.cregs: Dict[str, int] = {}
self.qelibinc = False
self.lexer = QasmLexer()
self.supported_format = False
self.parsedQasm: Optional[Qasm] = None
self.qubits: Dict[str, ops.Qid] = {}
self.functions = {
'sin': np.sin,
'cos': np.cos,
'tan': np.tan,
'exp': np.exp,
'ln': np.log,
'sqrt': np.sqrt,
'acos': np.arccos,
'atan': np.arctan,
'asin': np.arcsin,
}
self.binary_operators = {
'+': operator.add,
'-': operator.sub,
'*': operator.mul,
'/': operator.truediv,
'^': operator.pow,
}
basic_gates: Dict[str, QasmGateStatement] = {
'CX':
QasmGateStatement(qasm_gate='CX',
cirq_gate=CX,
num_params=0,
num_args=2),
'U':
QasmGateStatement(
qasm_gate='U',
num_params=3,
num_args=1,
# QasmUGate expects half turns
cirq_gate=(lambda params: QasmUGate(*[p / np.pi for p in params])),
),
}
qelib_gates = {
'rx':
QasmGateStatement(qasm_gate='rx',
cirq_gate=(lambda params: ops.rx(params[0])),
num_params=1,
num_args=1),
'ry':
QasmGateStatement(qasm_gate='ry',
cirq_gate=(lambda params: ops.ry(params[0])),
num_params=1,
num_args=1),
'rz':
QasmGateStatement(qasm_gate='rz',
cirq_gate=(lambda params: ops.rz(params[0])),
num_params=1,
num_args=1),
'id':
QasmGateStatement(qasm_gate='id',
cirq_gate=ops.IdentityGate(1),
num_params=0,
num_args=1),
'u1':
QasmGateStatement(
qasm_gate='u1',
cirq_gate=(lambda params: QasmUGate(0, 0, params[0] / np.pi)),
num_params=1,
num_args=1,
),
'u2':
QasmGateStatement(
qasm_gate='u2',
cirq_gate=(lambda params: QasmUGate(0.5, params[0] / np.pi, params[
1] / np.pi)),
num_params=2,
num_args=1,
),
'u3':
QasmGateStatement(
qasm_gate='u3',
num_params=3,
num_args=1,
cirq_gate=(lambda params: QasmUGate(*[p / np.pi for p in params])),
),
'x':
QasmGateStatement(qasm_gate='x',
num_params=0,
num_args=1,
cirq_gate=ops.X),
'y':
QasmGateStatement(qasm_gate='y',
num_params=0,
num_args=1,
cirq_gate=ops.Y),
'z':
QasmGateStatement(qasm_gate='z',
num_params=0,
num_args=1,
cirq_gate=ops.Z),
'h':
QasmGateStatement(qasm_gate='h',
num_params=0,
num_args=1,
cirq_gate=ops.H),
's':
QasmGateStatement(qasm_gate='s',
num_params=0,
num_args=1,
cirq_gate=ops.S),
't':
QasmGateStatement(qasm_gate='t',
num_params=0,
num_args=1,
cirq_gate=ops.T),
'cx':
QasmGateStatement(qasm_gate='cx',
cirq_gate=CX,
num_params=0,
num_args=2),
'cy':
QasmGateStatement(qasm_gate='cy',
cirq_gate=ops.ControlledGate(ops.Y),
num_params=0,
num_args=2),
'cz':
QasmGateStatement(qasm_gate='cz',
cirq_gate=ops.CZ,
num_params=0,
num_args=2),
'ch':
QasmGateStatement(qasm_gate='ch',
cirq_gate=ops.ControlledGate(ops.H),
num_params=0,
num_args=2),
'swap':
QasmGateStatement(qasm_gate='swap',
cirq_gate=ops.SWAP,
num_params=0,
num_args=2),
'cswap':
QasmGateStatement(qasm_gate='cswap',
num_params=0,
num_args=3,
cirq_gate=ops.CSWAP),
'ccx':
QasmGateStatement(qasm_gate='ccx',
num_params=0,
num_args=3,
cirq_gate=ops.CCX),
'sdg':
QasmGateStatement(qasm_gate='sdg',
num_params=0,
num_args=1,
cirq_gate=ops.S**-1),
'tdg':
QasmGateStatement(qasm_gate='tdg',
num_params=0,
num_args=1,
cirq_gate=ops.T**-1),
}
all_gates = {**basic_gates, **qelib_gates}
tokens = QasmLexer.tokens
start = 'start'
precedence = (
('left', '+', '-'),
('left', '*', '/'),
('right', '^'),
)
def p_start(self, p):
"""start : qasm"""
p[0] = p[1]
def p_qasm_format_only(self, p):
"""qasm : format"""
self.supported_format = True
p[0] = Qasm(self.supported_format, self.qelibinc, self.qregs,
self.cregs, self.circuit)
def p_qasm_no_format_specified_error(self, p):
"""qasm : QELIBINC
| circuit"""
if self.supported_format is False:
raise QasmException("Missing 'OPENQASM 2.0;' statement")
def p_qasm_include(self, p):
"""qasm : qasm QELIBINC"""
self.qelibinc = True
p[0] = Qasm(self.supported_format, self.qelibinc, self.qregs,
self.cregs, self.circuit)
def p_qasm_circuit(self, p):
"""qasm : qasm circuit"""
p[0] = Qasm(self.supported_format, self.qelibinc, self.qregs,
self.cregs, p[2])
def p_format(self, p):
"""format : FORMAT_SPEC"""
if p[1] != "2.0":
raise QasmException(
"Unsupported OpenQASM version: {}, "
"only 2.0 is supported currently by Cirq".format(p[1]))
# circuit : new_reg circuit
# | gate_op circuit
# | measurement circuit
# | empty
def p_circuit_reg(self, p):
"""circuit : new_reg circuit"""
p[0] = self.circuit
def p_circuit_gate_or_measurement(self, p):
"""circuit : circuit gate_op
| circuit measurement"""
self.circuit.append(p[2])
p[0] = self.circuit
def p_circuit_empty(self, p):
"""circuit : empty"""
p[0] = self.circuit
# qreg and creg
def p_new_reg(self, p):
"""new_reg : QREG ID '[' NATURAL_NUMBER ']' ';'
| CREG ID '[' NATURAL_NUMBER ']' ';'"""
name, length = p[2], p[4]
if name in self.qregs.keys() or name in self.cregs.keys():
raise QasmException("{} is already defined at line {}".format(
name, p.lineno(2)))
if length == 0:
raise QasmException(
"Illegal, zero-length register '{}' at line {}".format(
name, p.lineno(4)))
if p[1] == "qreg":
self.qregs[name] = length
else:
self.cregs[name] = length
p[0] = (name, length)
# gate operations
# gate_op : ID qargs
# | ID ( params ) qargs
def p_gate_op_no_params(self, p):
"""gate_op : ID qargs"""
self._resolve_gate_operation(p[2], gate=p[1], p=p, params=[])
def p_gate_op_with_params(self, p):
"""gate_op : ID '(' params ')' qargs"""
self._resolve_gate_operation(args=p[5], gate=p[1], p=p, params=p[3])
def _resolve_gate_operation(self, args: List[List[ops.Qid]], gate: str,
p: Any, params: List[float]):
gate_set = self.basic_gates if not self.qelibinc else self.all_gates
if gate not in gate_set.keys():
msg = 'Unknown gate "{}" at line {}{}'.format(
gate,
p.lineno(1),
", did you forget to include qelib1.inc?"
if not self.qelibinc else "",
)
raise QasmException(msg)
p[0] = gate_set[gate].on(args=args, params=params, lineno=p.lineno(1))
# params : parameter ',' params
# | parameter
def p_params_multiple(self, p):
"""params : expr ',' params"""
p[3].insert(0, p[1])
p[0] = p[3]
def p_params_single(self, p):
"""params : expr """
p[0] = [p[1]]
# expr : term
# | func '(' expression ')' """
# | binary_op
# | unary_op
def p_expr_term(self, p):
"""expr : term"""
p[0] = p[1]
def p_expr_parens(self, p):
"""expr : '(' expr ')'"""
p[0] = p[2]
def p_expr_function_call(self, p):
"""expr : ID '(' expr ')'"""
func = p[1]
if func not in self.functions.keys():
raise QasmException(
"Function not recognized: '{}' at line {}".format(
func, p.lineno(1)))
p[0] = self.functions[func](p[3])
def p_expr_unary(self, p):
"""expr : '-' expr
| '+' expr"""
if p[1] == '-':
p[0] = -p[2]
else:
p[0] = p[2]
def p_expr_binary(self, p):
"""expr : expr '*' expr
| expr '/' expr
| expr '+' expr
| expr '-' expr
| expr '^' expr
"""
p[0] = self.binary_operators[p[2]](p[1], p[3])
def p_term(self, p):
"""term : NUMBER
| NATURAL_NUMBER
| PI"""
p[0] = p[1]
# qargs : qarg ',' qargs
# | qarg ';'
def p_args_multiple(self, p):
"""qargs : qarg ',' qargs"""
p[3].insert(0, p[1])
p[0] = p[3]
def p_args_single(self, p):
"""qargs : qarg ';'"""
p[0] = [p[1]]
# qarg : ID
# | ID '[' NATURAL_NUMBER ']'
def p_quantum_arg_register(self, p):
"""qarg : ID """
reg = p[1]
if reg not in self.qregs.keys():
raise QasmException(
'Undefined quantum register "{}" at line {}'.format(
reg, p.lineno(1)))
qubits = []
for idx in range(self.qregs[reg]):
arg_name = self.make_name(idx, reg)
if arg_name not in self.qubits.keys():
self.qubits[arg_name] = NamedQubit(arg_name)
qubits.append(self.qubits[arg_name])
p[0] = qubits
# carg : ID
# | ID '[' NATURAL_NUMBER ']'
def p_classical_arg_register(self, p):
"""carg : ID """
reg = p[1]
if reg not in self.cregs.keys():
raise QasmException(
'Undefined classical register "{}" at line {}'.format(
reg, p.lineno(1)))
p[0] = [self.make_name(idx, reg) for idx in range(self.cregs[reg])]
def make_name(self, idx, reg):
return str(reg) + "_" + str(idx)
def p_quantum_arg_bit(self, p):
"""qarg : ID '[' NATURAL_NUMBER ']' """
reg = p[1]
idx = p[3]
arg_name = self.make_name(idx, reg)
if reg not in self.qregs.keys():
raise QasmException(
'Undefined quantum register "{}" at line {}'.format(
reg, p.lineno(1)))
size = self.qregs[reg]
if idx >= size:
raise QasmException('Out of bounds qubit index {} '
'on register {} of size {} '
'at line {}'.format(idx, reg, size,
p.lineno(1)))
if arg_name not in self.qubits.keys():
self.qubits[arg_name] = NamedQubit(arg_name)
p[0] = [self.qubits[arg_name]]
def p_classical_arg_bit(self, p):
"""carg : ID '[' NATURAL_NUMBER ']' """
reg = p[1]
idx = p[3]
arg_name = self.make_name(idx, reg)
if reg not in self.cregs.keys():
raise QasmException(
'Undefined classical register "{}" at line {}'.format(
reg, p.lineno(1)))
size = self.cregs[reg]
if idx >= size:
raise QasmException('Out of bounds bit index {} '
'on classical register {} of size {} '
'at line {}'.format(idx, reg, size,
p.lineno(1)))
p[0] = [arg_name]
# measurement operations
# measurement : MEASURE qarg ARROW carg
def p_measurement(self, p):
"""measurement : MEASURE qarg ARROW carg ';'"""
qreg = p[2]
creg = p[4]
if len(qreg) != len(creg):
raise QasmException(
'mismatched register sizes {} -> {} for measurement '
'at line {}'.format(len(qreg), len(creg), p.lineno(1)))
p[0] = [
ops.MeasurementGate(num_qubits=1, key=creg[i]).on(qreg[i])
for i in range(len(qreg))
]
def p_error(self, p):
if p is None:
raise QasmException('Unexpected end of file')
raise QasmException("""Syntax error: '{}'
{}
at line {}, column {}""".format(p.value, self.debug_context(p), p.lineno,
self.find_column(p)))
def find_column(self, p):
line_start = self.qasm.rfind('\n', 0, p.lexpos) + 1
return (p.lexpos - line_start) + 1
def p_empty(self, p):
"""empty :"""
def parse(self, qasm: str) -> Qasm:
if self.parsedQasm is None:
self.qasm = qasm
self.lexer.input(self.qasm)
self.parsedQasm = self.parser.parse(lexer=self.lexer)
return self.parsedQasm
def debug_context(self, p):
debug_start = max(self.qasm.rfind('\n', 0, p.lexpos) + 1, p.lexpos - 5)
debug_end = min(self.qasm.find('\n', p.lexpos, p.lexpos + 5),
p.lexpos + 5)
return ("..." + self.qasm[debug_start:debug_end] + "\n" +
(" " * (3 + p.lexpos - debug_start)) + "^")