Python:实现经典ripple adder涟波加法器算法
from qiskit import Aer, QuantumCircuit, execute
from qiskit.providers import Backend
def store_two_classics(val1: int, val2: int) -> tuple[QuantumCircuit, str, str]:
"""
Generates a Quantum Circuit which stores two classical integers
Returns the circuit and binary representation of the integers
"""
x, y = bin(val1)[2:], bin(val2)[2:] # Remove leading '0b'
# Ensure that both strings are of the same length
if len(x) > len(y):
y = y.zfill(len(x))
else:
x = x.zfill(len(y))
# We need (3 * number of bits in the larger number)+1 qBits
# The second parameter is the number of classical registers, to measure the result
circuit = QuantumCircuit((len(x) * 3) + 1, len(x) + 1)
# We are essentially "not-ing" the bits that are 1
# Reversed because its easier to perform ops on more significant bits
for i in range(len(x)):
if x[::-1][i] == "1":
circuit.x(i)
for j in range(len(y)):
if y[::-1][j] == "1":
circuit.x(len(x) + j)
return circuit, x, y
def full_adder(
circuit: QuantumCircuit,
input1_loc: int,
input2_loc: int,
carry_in: int,
carry_out: int,
):
"""
Quantum Equivalent of a Full Adder Circuit
CX/CCX is like 2-way/3-way XOR
"""
circuit.ccx(input1_loc, input2_loc, carry_out)
circuit.cx(input1_loc, input2_loc)
circuit.ccx(input2_loc, carry_in, carry_out)
circuit.cx(input2_loc, carry_in)
circuit.cx(input1_loc, input2_loc)
def ripple_adder(
val1: int,
val2: int,
backend: Backend = Aer.get_backend("qasm_simulator"), # noqa: B008
) -> int:
if val1 < 0 or val2 < 0:
raise ValueError("Both Integers must be positive!")
# Store the Integers
circuit, x, y = store_two_classics(val1, val2)
for i in range(len(x)):
full_adder(circuit, i, len(x) + i, len(x) + len(y) + i, len(x) + len(y) + i + 1)
circuit.barrier() # Optional, just for aesthetics
# Measure the resultant qBits
for i in range(len(x) + 1):
circuit.measure([(len(x) * 2) + i], [i])
res = execute(circuit, backend, shots=1).result()
# The result is in binary. Convert it back to int
return int(list(res.get_counts())[0], 2)
if __name__ == "__main__":
import doctest
doctest.testmod()