PennyLaneAI / PennyLaneAI/catalyst

Drawing the circuit with catalyst.measure fails

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Dominant language
Python
Stars
234
Forks
84
Avg merge
2d 15h
Merged PRs (30d)
66

Description

Issue description

Description of the issue - Circuit drawing fails when using mid circuit measurment.

  • Expected behavior: (What you expect to happen)
    Draw the circuit

  • Actual behavior: (What actually happens)
    Error

  • Reproduces how often: (What percentage of the time does it reproduce?)
    100

  • System information: (post the output of import pennylane as qml; qml.about())
    Name: PennyLane
    Version: 0.34.0
    Summary: PennyLane is a Python quantum machine learning library by Xanadu Inc.
    Home-page: https://github.com/PennyLaneAI/pennylane
    Author:
    Author-email:
    License: Apache License 2.0
    Location: /envs/catalyst/lib/python3.10/site-packages
    Requires: appdirs, autograd, autoray, cachetools, networkx, numpy, pennylane-lightning, requests, rustworkx, scipy, semantic-version, toml, typing-extensions
    Required-by: PennyLane-Catalyst, PennyLane-Lightning
    Platform info: Linux-6.2.0-37-generic-x86_64-with-glibc2.35
    Python version: 3.10.13
    Numpy version: 1.26.3
    Scipy version: 1.12.0
    Installed devices:

  • lightning.qubit (PennyLane-Lightning-0.34.0)
  • default.gaussian (PennyLane-0.34.0)
  • default.mixed (PennyLane-0.34.0)
  • default.qubit (PennyLane-0.34.0)
  • default.qubit.autograd (PennyLane-0.34.0)
  • default.qubit.jax (PennyLane-0.34.0)
  • default.qubit.legacy (PennyLane-0.34.0)
  • default.qubit.tf (PennyLane-0.34.0)
  • default.qubit.torch (PennyLane-0.34.0)
  • default.qutrit (PennyLane-0.34.0)
  • null.qubit (PennyLane-0.34.0)
Source code and tracebacks
@qjit
@qml.qnode(qml.device("lightning.qubit", wires=2,shots=100))
def circuit(theta):
    qml.Hadamard(wires=0)
    qml.RX(theta, wires=1)
    qml.CNOT(wires=[0,1])
    m=measure(wires=0)
    return qml.expval(qml.PauliZ(wires=1)),m

print(qml.draw(circuit)(1.2))

Error:
catalyst.utils.exceptions.CompileError: catalyst.measure can only be used from within @qjit.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the provided circuit with qml.draw(circuit), then inspect how @qjit and catalyst.measure interact at the drawing boundary. The issue is done when the reproduced circuit draws successfully without the “can only be used from within @qjit” CompileError.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

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