The approach in https://github.com/pasqal-io/qadence/pull/469 was instead to change the Noise dataclass in qadence.noise.protocols to include the same options, but then there was already an option there called DEPOLARIZING which got changed to DEPOLARIZING_PYQ... I am not so sure what is the best approach here, this should be revised.
Furthermore, I have also drafted a transpilation function to add noise to gates within a composite block or circuit. It works like this:
from qadence import RX, DigitalNoise, set_noise, chain, run
n_qubits = 2
block = chain(RX(i, f"theta_{i}") for i in range(n_qubits))
noise = DigitalNoise.bitflip(error_probability = 0.1)
# The function changes the block in place:
set_noise(block, noise)
run(block)
The code above should add the defined bitflip protocol to every gate in the block. It should also work if it is a QuantumCircuit. There is an extra optional argument to specify the type of block we want to apply noise to. E.g., let's say we want to apply noise only to X gates, then it will run an if isinstance(block, target_class): ... at every leaf block in the block tree:
from qadence import RX, X, DigitalNoise, set_noise, chain, run
n_qubits = 2
block = chain(RX(i, f"theta_{i}") for i in range(n_qubits))
noise = DigitalNoise.bitflip(error_probability = 0.1)
# The function changes the block in place:
set_noise(block, noise, target_class = X)
run(block)
The snippet above will just return a statevector because there exists no X gates in that composite block. We can also try to print the noise for each of the gates and see that it works:
from qadence import RX, X, DigitalNoise, set_noise, chain, run
n_qubits = 2
block = chain(RX(0, "theta"), X(0))
noise = DigitalNoise.bitflip(error_probability = 0.1)
set_noise(block, noise, target_class = X)
for block in block.blocks:
print(block.noise)
---
> None
> BitFlip(prob: 0.1)
Including the noise in each block string: if added, check how it behaves with visualization.
Properly review the code, and check if something else from https://github.com/pasqal-io/qadence/pull/469 should be added. See about harmonizing the DigitalNoise with the Noise and etc... I like the interface of the NoiseProtocol from pyq, so it would be nice to still keep it when using it in Qadence.
Add tests! While writing some finals things for this MR description I think I ran an instance of set_noise that did not apply the noise correctly... But now I was trying to replicate it to put it here and I couldn't 😅 So yes for sure test it thoroughly.
Description
Ongoing work in adding the noise from PyQ. Supersedes https://github.com/pasqal-io/qadence/pull/469.
Currently in this branch the basics should be working:
Note that currently the
DigitalNoiseis simply a name alias for theNoiseProtocolclass directly from PyQ, which you can find here: https://github.com/pasqal-io/pyqtorch/blob/main/pyqtorch/noise/protocol.py.The approach in https://github.com/pasqal-io/qadence/pull/469 was instead to change the
Noisedataclass inqadence.noise.protocolsto include the same options, but then there was already an option there calledDEPOLARIZINGwhich got changed toDEPOLARIZING_PYQ... I am not so sure what is the best approach here, this should be revised.Furthermore, I have also drafted a transpilation function to add noise to gates within a composite block or circuit. It works like this:
The code above should add the defined bitflip protocol to every gate in the block. It should also work if it is a
QuantumCircuit. There is an extra optional argument to specify the type of block we want to apply noise to. E.g., let's say we want to apply noise only toXgates, then it will run anif isinstance(block, target_class): ...at every leaf block in the block tree:The snippet above will just return a statevector because there exists no
Xgates in that composite block. We can also try to print the noise for each of the gates and see that it works:What is left to do:
_to_dictand_from_dictstuff in https://github.com/pasqal-io/qadence/pull/469DigitalNoisewith theNoiseand etc... I like the interface of theNoiseProtocolfrom pyq, so it would be nice to still keep it when using it in Qadence.set_noisethat did not apply the noise correctly... But now I was trying to replicate it to put it here and I couldn't 😅 So yes for sure test it thoroughly.