Unavailability of Probabilities in result after successfull simulation

[Suraj1409]

Informations

Qiskit = 1.0.2
Qiskit-aer = 0.14.1
Qiskit-aer-gpu = 0.14.1

What is the current behavior?

I have Nvidia A100 GPU with 80GB memory, and I am trying to simulate 33 qubit circuit (statevector simulation) with single precision which will take around 64 GB memory, but when I run the circuit it didnt produce probabilities in the result, but the status of simulation is completed and time taken is 0.0025 sec

Need a guide for it

[chrisamirani]

Hey @Suraj1409 Are you able to share your code here? If not everything, at least the part where you define your circuit and where you run the backend

[Suraj1409]

from qiskit import *
from qiskit_aer import Aer, AerSimulator
import numpy as np
from qiskit.circuit.library import MCXGate

number_of_qubit = 33
target = [2]

def single_oracle(qc, q):
qc.barrier(q)
n = len(q)
qc.h(q[n - 1])
qc.append(MCXGate(n - 1), q)
qc.h(q[n - 1])
qc.barrier(q)

def diffusion_operator(qc, q):
qc.barrier(q)
n = len(q)
qc.h(q)
qc.x(q)
qc.h(q[n - 1])
qc.append(MCXGate(n - 1), q)
qc.h(q[n - 1])
qc.barrier(q)
qc.x(q)
qc.h(q)
qc.barrier(q)

def grover(qc, q, target):
n = len(q)
n_iterator = int(round((np.pi / 4)*np.sqrt(2**n / len(target)) - 0.5))
# print(n_iterator)
for i in range(0, n_iterator):
for t in target:
temp = t
for i in range(0, n):
if (temp % 2) == 0:
qc.x(q[i])
temp = int(temp / 2)
single_oracle(qc, q)
temp = t
for i in range(0, n):
if (temp % 2) == 0:
qc.x(q[i])
temp = int(temp / 2)
qc.barrier(q)
diffusion_operator(qc, q)

q = QuantumRegister(number_of_qubit)
c = ClassicalRegister(number_of_qubit)
qc = QuantumCircuit(q, c)
qc.h(q)
grover(qc, q, target)
qc.measure(q, c)

backend = Aer.get_backend('aer_simulator_statevector_gpu')
backend.set_options(precision='single')

job_cu = backend.run(qc, shots=3000,cuStateVec_enable=True)

result_cu = job_cu.result()

print("CuStateVec Output : ")
print(result_cu.status)
print(result_cu.time_taken)

[chrisamirani]

Thx @Suraj1409 so when you run job_cu.result().get_counts() you get nothing? You should be able to get the probabilities with that.

[Suraj1409]

Nothing gets print, even i tried to print job_cu.result() all parameters get printed but not probabilities