Python/quantum/q_full_adder.py
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2023-08-29 15:18:10 +02:00

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Python

"""
Build the quantum full adder (QFA) for any sum of
two quantum registers and one carry in. This circuit
is designed using the Qiskit framework. This
experiment run in IBM Q simulator with 1000 shots.
.
References:
https://www.quantum-inspire.com/kbase/full-adder/
"""
import math
import qiskit
def quantum_full_adder(
input_1: int = 1, input_2: int = 1, carry_in: int = 1
) -> qiskit.result.counts.Counts:
"""
# >>> q_full_adder(inp_1, inp_2, cin)
# the inputs can be 0/1 for qubits in define
# values, or can be in a superposition of both
# states with hadamard gate using the input value 2.
# result for default values: {11: 1000}
qr_0: ──■────■──────────────■──
│ ┌─┴─┐ ┌─┴─┐
qr_1: ──■──┤ X ├──■────■──┤ X ├
│ └───┘ │ ┌─┴─┐└───┘
qr_2: ──┼─────────■──┤ X ├─────
┌─┴─┐ ┌─┴─┐└───┘
qr_3: ┤ X ├─────┤ X ├──────────
└───┘ └───┘
cr: 2/═════════════════════════
Args:
input_1: input 1 for the circuit.
input_2: input 2 for the circuit.
carry_in: carry in for the circuit.
Returns:
qiskit.result.counts.Counts: sum result counts.
>>> quantum_full_adder(1, 1, 1)
{'11': 1000}
>>> quantum_full_adder(0, 0, 1)
{'01': 1000}
>>> quantum_full_adder(1, 0, 1)
{'10': 1000}
>>> quantum_full_adder(1, -4, 1)
Traceback (most recent call last):
...
ValueError: inputs must be positive.
>>> quantum_full_adder('q', 0, 1)
Traceback (most recent call last):
...
TypeError: inputs must be integers.
>>> quantum_full_adder(0.5, 0, 1)
Traceback (most recent call last):
...
ValueError: inputs must be exact integers.
>>> quantum_full_adder(0, 1, 3)
Traceback (most recent call last):
...
ValueError: inputs must be less or equal to 2.
"""
if (
isinstance(input_1, str)
or isinstance(input_2, str)
or isinstance(carry_in, str)
):
raise TypeError("inputs must be integers.")
if (input_1 < 0) or (input_2 < 0) or (carry_in < 0):
raise ValueError("inputs must be positive.")
if (
(math.floor(input_1) != input_1)
or (math.floor(input_2) != input_2)
or (math.floor(carry_in) != carry_in)
):
raise ValueError("inputs must be exact integers.")
if (input_1 > 2) or (input_2 > 2) or (carry_in > 2):
raise ValueError("inputs must be less or equal to 2.")
# build registers
qr = qiskit.QuantumRegister(4, "qr")
cr = qiskit.ClassicalRegister(2, "cr")
# list the entries
entry = [input_1, input_2, carry_in]
quantum_circuit = qiskit.QuantumCircuit(qr, cr)
for i in range(3):
if entry[i] == 2:
quantum_circuit.h(i) # for hadamard entries
elif entry[i] == 1:
quantum_circuit.x(i) # for 1 entries
elif entry[i] == 0:
quantum_circuit.i(i) # for 0 entries
# build the circuit
quantum_circuit.ccx(0, 1, 3) # ccx = toffoli gate
quantum_circuit.cx(0, 1)
quantum_circuit.ccx(1, 2, 3)
quantum_circuit.cx(1, 2)
quantum_circuit.cx(0, 1)
quantum_circuit.measure([2, 3], cr) # measure the last two qbits
backend = qiskit.Aer.get_backend("aer_simulator")
job = qiskit.execute(quantum_circuit, backend, shots=1000)
return job.result().get_counts(quantum_circuit)
if __name__ == "__main__":
print(f"Total sum count for state is: {quantum_full_adder(1, 1, 1)}")