NVIDIA / NVIDIA/cuda-quantum

Returning vectors from cudaq.run does not work on remote simulator

Open
#3,012 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

stale-notified
Dominant language
C++
Stars
1.1k
Forks
456
Avg merge
1d 22h
Merged PRs (30d)
165

Description

Required prerequisites
  • Consult the security policy. If reporting a security vulnerability, do not report the bug using this form. Use the process described in the policy to report the issue.
  • Make sure you've read the documentation. Your issue may be addressed there.
  • Search the issue tracker to verify that this hasn't already been reported. +1 or comment there if it has.
  • If possible, make a PR with a failing test to give us a starting point to work on!
Describe the bug

The following code fails to run on remote simulator (see example in https://github.com/NVIDIA/cuda-quantum/issues/2964 for similar python code that fails on remote sim as well)

Steps to reproduce the bug
#include <cudaq.h>

struct K9 {
  std::vector<bool> operator()() __qpu__ {
    cudaq::qvector q(5);
    x(q);
    return mz(q);
  }
};

int main() {
  auto syndromes = cudaq::run(10, K9{});
  for (auto &s : syndromes) {
    for (auto ss : s)
      printf("%d ", (int)ss);
    printf("\n");
  }
}

Command:

nvq++ -fenable-cudaq-run --target quantinuum --emulate file.cpp

Result:

loses the malloc function declaration in the remote rest JIT pipeline
loc(callsite("-":4:10 at "run.cpp":7:5)): error: 'func.call' op 'malloc' does not reference a valid function
terminate called after throwing an instance of 'std::runtime_error'
  what():  Could not successfully apply quake-synth.
Aborted (core dumped)

### Expected behavior

Runs successfully

### Is this a regression? If it is, put the last known working version (or commit) here.

Not a regression

### Environment

- **CUDA-Q version**: 
- **Python version**: 
- **C++ compiler**: 
- **Operating system**: 


### Suggestions

_No response_

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 reproducing file.cpp with nvq++ -fenable-cudaq-run --target quantinuum --emulate file.cpp, focusing on cudaq::run and the remote JIT pipeline. Trace the reported malloc failure through quake-synth; done means the vector-returning example runs successfully on the remote simulator and prints the returned syndromes.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
compilers, distributed-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.