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cuTile Python to cuTile.jl Conversion

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Efficiently convert cuTile Python kernels to Julia.

by nvidia2.8k stars on nvidia/skills
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Updated Aug 7, 2026
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What cuTile Python to cuTile.jl Conversion does

The cuTile Python to cuTile.jl Conversion skill facilitates the translation of cuTile Python GPU kernels, specifically those marked with @ct.kernel, into their Julia equivalents. This process encompasses various critical transformations such as adapting kernel syntax from Python to Julia's function definitions, converting array indexing from 0-based to 1-based, and addressing differences in memory layouts and type systems. The skill is particularly useful for developers and researchers who need to port existing Python kernels to Julia for performance optimization or to leverage Julia's capabilities in numerical computing.

The conversion workflow is structured to guide users through the necessary steps: analyzing the original Python kernel, writing the corresponding Julia kernel, and validating the output. Users can reference detailed documentation for debugging common errors, understanding critical rules that govern the conversion process, and testing their Julia implementations against established patterns. The skill also includes a set of example conversions that serve as practical references, showcasing how to handle various operations such as element-wise addition, matrix multiplication, and softmax computations.

This skill is ideal for data scientists, machine learning engineers, and developers who are transitioning projects from Python to Julia or who are looking to optimize GPU kernel performance in Julia. By providing a systematic approach to kernel conversion, it reduces the potential for errors and streamlines the development process, allowing users to focus on enhancing their applications rather than getting bogged down by syntax and operational differences between the two languages.

In summary, the cuTile Python to cuTile.jl Conversion skill is a valuable tool for anyone involved in GPU programming with cuTile, offering a clear pathway for translating Python code into Julia while ensuring compatibility and performance are maintained.

When to use it

Use this skill when you need to convert or port existing cuTile Python kernels to Julia for performance or compatibility reasons.

When not to use it

This skill is not suitable for projects that do not involve cuTile or for users unfamiliar with GPU programming concepts.

What you can build with it

Porting a Machine Learning Model

You have a machine learning model written in cuTile Python and want to optimize it using Julia's performance capabilities.

Debugging Kernel Errors

While translating a kernel, you encounter a MethodError; use the debugging resources to identify and fix the issue.

Learning Julia GPU Programming

You are transitioning from Python to Julia for GPU programming and need a structured way to convert existing kernels.

How to install cuTile Python to cuTile.jl Conversion

View source

1. Install with the skills CLI

npx skills add nvidia/skills/tilegym-converting-cutile-to-julia --agent claude-code

2. Or install it manually

Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.

Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs

Inside SKILL.md

Written by nvidia

cuTile Python → cuTile.jl (Julia) Conversion

Convert @ct.kernel Python kernels to Julia function ... end cuTile.jl kernels.

Workflow Selection

Architecture

Julia kernels are standalone — no Python bridge, no pytest integration. The Julia sub-project lives in julia/ at the repo root with its own Project.toml for dependency management.

julia/                          # Self-contained Julia sub-project
├── Project.toml                # Dependencies: CUDA.jl, cuTile.jl, NNlib.jl, Test
├── kernels/                    # cuTile.jl kernel implementations
│   ├── add.jl                  # ← Ground-truth: 1D element-wise with alpha scaling (tensor+tensor, tensor+scalar)
│   ├── matmul.jl               # ← Ground-truth: 2D tiled MMA, standard Julia layout (M,K)×(K,N)→(M,N)
│   └── softmax.jl              # ← Ground-truth: 3 strategies (TMA, online, chunked) using ct.load/ct.store
└── test/                       # Julia-native tests (using Test stdlib)
    ├── runtests.jl             # Test runner entry point
    ├── test_add.jl
    ├── test_matmul.jl
    └── test_softmax.jl

Ground-truth reference: Always consult julia/kernels/*.jl and julia/test/*.jl for patterns that compile and pass tests. These are the canonical examples of working cuTile.jl code.

Instructions

  1. Analyze the Python kernel: identify patterns, shapes, dtypes, operations
  2. Write Julia kerneljulia/kernels/<op>.jl with cuTile.jl kernel + bridge function(s)
  3. Convert kernel signature (see translations/workflow.md Phase 2)
  4. Convert kernel body (apply references/api-mapping.md + references/critical-rules.md)
  5. Write Julia testjulia/test/test_<op>.jl using Test stdlib + NNlib.jl for reference
  6. Register test — add include(...) in julia/test/runtests.jl
  7. Validate — run the bundled validator: python <skill-dir>/scripts/validate_cutile_jl.py <file.jl>
  8. Test — run julia --project=julia/ julia/test/runtests.jl

Full conversion checklist with post-conversion verification → translations/workflow.md

⚠️ Top Pitfalls

The most dangerous translation errors. Full rules (17 total) in references/critical-rules.md.

#PitfallOne-line fix
1ct.full() doesn't exist in JuliaUse fill(val, shape), zeros(T, dims...), or ones(T, dims...)
2max(a, b) on tiles → IRErrorUse max.(a, b) (broadcast dot)
3IRError / MethodError mentioning IRStructurizerCompiler bug — file upstream with minimal reproducer
4ct.launch arg order silently wrongArgs are positional — match kernel signature exactly
5ct.load with order — index positions wrongorder remaps BOTH shape AND index (Critical Rule 16)

Worked Examples

Side-by-side Python → Julia conversions matching the released Julia kernels in julia/kernels/. Each directory contains cutile_python.py (before) and cutile_julia.jl (after).

#ExampleKey PatternsWhen to Reference
01add1D ct.load/ct.store, alpha scaling, scalar broadcast, fill/zeros, keyword load/storeStarting point; basic TMA + element-wise patterns
02matmulmuladd, TF32 conversion, K-loop with for, 2D swizzle, standard Julia layout, ct.@compiler_optionsMMA / tensor core operations
03softmaxPersistent scheduling, for loops, gather/scatter, padding_mode, multi-passLarge-tensor reduction patterns

These match the released kernels in julia/kernels/ (add.jl, matmul.jl, softmax.jl). The examples are simplified teaching versions — always consult julia/kernels/*.jl for the canonical, tested implementations.

Reference Documents

CategoryDocumentContent
Workflowstranslations/workflow.mdFull conversion workflow with todo list, validation loop, checklist
Rulesreferences/critical-rules.md17 Critical Rules for cuTile Python → Julia conversion
APIreferences/api-mapping.mdPython↔Julia bidirectional API mapping + kernel patterns
Testingreferences/testing.mdJulia-native test patterns, tolerances, failure diagnosis
Debuggingreferences/debugging.mdJulia-specific error diagnosis + IR debug commands
Scriptsscripts/validate_cutile_jl.pyStatic validation for Julia anti-patterns (run it)
Ground Truthjulia/kernels/*.jl + julia/test/*.jlActual working implementations in the codebase

Environment Setup

Prerequisite — Julia: this skill requires the Julia version declared in julia/Project.toml under [compat] julia. If julia --version is missing or older than that, install from the official Julia site at https://julialang.org/install/ following the verified installer instructions for your OS. Resume below once julia --version is compatible.

Then, from the repo root:

# Install Julia dependencies declared in julia/Project.toml
julia --project=julia/ -e 'using Pkg; Pkg.instantiate()'

# Run tests
julia --project=julia/ julia/test/runtests.jl

Requirements:

  • Julia (minimum version declared in julia/Project.toml under [compat] julia)
  • CUDA 13.1+ driver
  • Blackwell GPU (compute capability 10+)
  • Dependencies managed via julia/Project.toml: CUDA.jl, cuTile.jl, NNlib.jl, Test

Frequently asked questions about cuTile Python to cuTile.jl Conversion

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