import json
import pennylane as qml
import pennylane.numpy as np
dev = qml.device("default.qubit", wires=3)
@qml.qnode(dev)
def circuit(weights):
# Build the circuit here
# Return the Y0xZ2 observable
def parameter_shift(weights):
"""Compute the gradient of the variational circuit given by the
circuit function using the parameter-shift rule.
Args:
weights (array): An array of floating-point numbers with size (2, 3).
Returns:
array: The gradient of the variational circuit. The shape should match
the input weights array.
"""
# Return the gradient calculated using the parameter-shift rule
# These functions are responsible for testing the solution.
def run(test_case_input: str) -> str:
ins = np.array(json.loads(test_case_input), requires_grad = True)
out = parameter_shift(ins).round(3).tolist()
return str(out)
def check(solution_output: str, expected_output: str) -> None:
solution_output = json.loads(solution_output)
expected_output = json.loads(expected_output)
assert np.allclose(solution_output, expected_output, atol=1e-2), "The gradient calculated isn't quite right."
# These are the public test cases
test_cases = [
('[[1,0.5,-0.765], [0.1,0,-0.654]]', '[[0.0, 0.0, 0.0], [0.0, -0.455, 0.0]]'),
('[[0.94,-0.2,6.03],[-2.6,-0.058,1.2]]', '[[0.03, -0.039, 0.0], [-0.034, 0.166, 0.0]]')
]
# This will run the public test cases locally
for i, (input_, expected_output) in enumerate(test_cases):
print(f"Running test case {i} with input '{input_}'...")
try:
output = run(input_)
except Exception as exc:
print(f"Runtime Error. {exc}")
else:
if message := check(output, expected_output):
print(f"Wrong Answer. Have: '{output}'. Want: '{expected_output}'.")
else:
print("Correct!")