CUDA-Q Guide

Purpose

Guide users through CUDA-Q installation, basic kernels, GPU simulation targets, QPU access, built-in applications, multi-GPU execution, and Python @cudaq.kernel authoring. For Qiskit-to-CUDA-Q ports, route to the qiskit-to-cudaq skill instead.

Prerequisites

• Python 3.10+ for Python CUDA-Q workflows.
• CUDA Toolkit and an NVIDIA GPU for GPU-accelerated targets on Linux.
• CPU-only simulation is available through qpp-cpu; macOS is CPU-only.
• C++ workflows require Linux or WSL and C++20.
• QPU workflows require provider-specific credentials and accounts.

Instructions

• Invoke with /cudaq-guide [argument].
• If no argument is given, display the onboarding menu and ask which topic the

user wants.

• Use the routing table below to choose the relevant reference file.
• Read local CUDA-Q documentation files when the answer depends on a specific

CUDA-Q version or backend behavior.

• Do not answer Qiskit porting questions from this skill; use

qiskit-to-cudaq.

Routing by Argument

Menu

CUDA-Q Getting Started

CUDA-Q is NVIDIA's unified quantum-classical programming model for CPUs, GPUs, and QPUs.
Supports Python and C++. Docs: https://nvidia.github.io/cuda-quantum/latest/

Choose a topic:
  /cudaq-guide install         Install CUDA-Q
  /cudaq-guide test-program    Write and run a Bell-state kernel
  /cudaq-guide gpu-sim         Accelerate simulation on NVIDIA GPUs
  /cudaq-guide qpu             Connect to real QPU hardware
  /cudaq-guide applications    Explore what you can build
  /cudaq-guide parallelize     Run across GPUs or QPUs
  /cudaq-guide author          Author @cudaq.kernel Python code

Reference Files

• [references/onboarding.md](references/onboarding.md): installation, test

program, GPU targets, QPU providers, application areas, parallelization modes, examples, and platform troubleshooting.

• [references/authoring.md](references/authoring.md): execution APIs,

kernel-language constraints, silent-failure pitfalls, recurring coding patterns, resource metrics, debugging, and validation.

Limitations

• Guidance targets CUDA-Q Python/C++ workflows, with authoring details focused

on decorator-mode Python APIs used in CUDA-Q 0.14 and 0.15.

• GPU and multi-GPU support depends on local CUDA-Q, CUDA Toolkit, driver, MPI,

and hardware availability.

• QPU access and target options are provider-specific and may change; verify

against local docs before giving operational steps.

Troubleshooting

• Import error after pip install cudaq: check Python 3.10+ and supported

OS.

• No GPU detected: verify CUDA Toolkit and nvidia-smi; fall back to

qpp-cpu.

• Kernel compile error: read [references/authoring.md](references/authoring.md)

and check the restricted kernel-language subset.

• Version-specific behavior differs: compare cudaq.version with the

latest documentation, then review relevant documentation or source changes when debugging an installed version that is not the latest release.

• QPU submission fails: verify provider credentials are set as environment

variables or through a secrets manager, never hardcoded.

• Documentation lookup fails: retry transient MCP or repository lookup once,

then fall back to local docs or official CUDA-Q documentation.