First of all, thank you for contributing! We welcome contributions of all forms, including but not limited to
- Bug fixes
- Proposing and implementing new features
- Documentation improvements and translations
- Improved error messages that are more user-friendly
- New test cases
- New examples
- Compiler performance enhancements
- High-quality blog posts and tutorials
- Participation in the Taichi forum
- Introduce Taichi to your friends or simply star the project on Github.
- Typo fixes in the documentation, code or comments (please go ahead and make a pull request for minor issues like these)
Please take some time to familiarize yourself with this contribution guide before making any changes.
Issues marked with "good first issue" are great chances for starters.
- Please first leave a note (e.g. I know how to fix this and would like to help!) on the issue, so that people know someone is already working on it. This helps prevent redundant work;
- If no core developer has commented and described a potential solution on the issue, please briefly describe your plan, and wait for a core developer to reply before you start. This helps keep implementations simple and effective.
Issues marked with "welcome contribution" are slightly more challenging but still friendly to beginners.
- Be pragmatic: practically solving problems is our ultimate goal.
- No overkills: always use easy solutions to solve easy problems, so that you have time and energy for real hard ones.
- Almost every design decision has pros and cons. A decision is good if its pros outweigh its cons. Always think about both sides.
- Debugging is hard. Changesets should be small so that sources of bugs can be easily pinpointed.
- Unit/integration tests are our friends.
"There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." — C.A.R. Hoare
One thing to keep in mind is that, Taichi was originally born as an academic research project. This usually means that some parts did not have the luxury to go through a solid design. While we are always trying to improve the code quality, it doesn't mean that the project is free from technical debts. Some places may be confusing or overly complicated. Whenever you spot one, you are more than welcome to shoot us a PR! :-)
A few tips for effective communication in the Taichi community:
- How much information one effectively conveys, is way more important than how many words one typed.
- Be constructive. Be polite. Be organized. Be concise.
- Bulleted lists are our friends.
- Proofread before you post: if you are the reader, can you understand what you typed?
- If you are not a native speaker, consider using a spell checker such as Grammarly.
Please base your discussion and feedback on facts, and not personal feelings. It is very important for all of us to maintain a friendly and blame-free community. Some examples:
This design could be confusing to new Taichi users.
This design is terrible.
- PRs with small changesets are preferred. A PR should ideally
address only one issue.
- It is fine to include off-topic trivial refactoring such as typo fixes;
- The reviewers reserve the right to ask PR authors to remove off-topic non-trivial changes.
- All commits in a PR will always be squashed and merged into master as a single commit.
- PR authors should not squash commits on their own;
- When implementing a complex feature, consider breaking it down into small PRs, to keep a more detailed development history and to interact with core developers more frequently.
- If you want early feedback from core developers
- Open a PR in Draft state on GitHub so that you can share your progress;
- Make sure you @ the corresponding developer in the comments or request the review.
- If you are making multiple PRs
- Independent PRs should be based on different branches
- PRs with dependencies should be raised only after all
prerequisite PRs are merged into
- Independent PRs should be based on different branches forking from
- All PRs should ideally come with corresponding tests;
- All PRs should come with documentation updates, except for internal compiler implementations;
- All PRs must pass continuous integration tests before they get merged;
- PR titles should follow PR tag rules;
- A great article from Google on how to have your PR merged quickly. [PDF]
- Please try to follow these tips from Google
- The merger should always squash and merge PRs into the master branch;
- The master branch is required to have a linear history;
- Make sure the PR passes continuous integration tests, except for cases like documentation updates;
- Make sure the title follows PR tag rules.
- Continuous Integration (CI) will build and test your commits in a PR in multiple environments.
- Currently, Taichi uses Github Actions (for OS X and Linux) and AppVeyor (for Windows).
- CI will be triggered every time you push commits to an open PR.
- You can prepend
[skip ci]to your commit message to avoid triggering CI. e.g.
[skip ci] This commit will not trigger CI
- A tick on the right of commit hash means CI passed, a cross means CI failed.
Locally, you can run
ti formatin the command line to re-format code style. Note that you have to install
yapf v0.29.0locally before you use
If you don't have these formatting tools locally, feel free to leverage GitHub actions: simply comment
/formatin a PR (e.g., #2481) and then Taichi Gardener will automatically format the code for you.
PR titles will be part of the commit history reflected in the
branch, therefore it is important to keep PR titles readable.
- Please always prepend at least one tag such as
[Lang]to PR titles:
- When using multiple tags, make sure there is exactly one space between tags;
- E.g., "[Lang][refactor]" (no space) should be replaced by "[Lang][refactor]";
- The first letter of the PR title body should be capitalized:
[Doc] improve documentationshould be replaced by
[Doc] Improve documentation;
[Lang] "ti.sqr(x)" is now deprecatedis fine because
"is a symbol.
- Please do not include back quotes ("`") in PR titles.
- For example, "[Metal] Support bitmasked SNode", "[Vulkan] ti.atomic_min/max support", or "[Opt][ir] Enhanced intra-function optimizations".
Frequently used tags:
[LLVM]: the LLVM backend shared by CPUs and CUDA;
[Lang]: frontend language features, including syntax sugars;
[Std]: standard library, e.g.
[Sparse]: sparse computation;
[IR]: intermediate representation;
[Opt]: IR optimization passes;
[GUI]: the built-in GUI system;
[Refactor]: code refactoring;
[CLI]: commandline interfaces, e.g. the
[Doc]: documentation under
[Example]: examples under
[Test]: adding or improving tests under
[Linux]: Linux platform;
[Mac]: macOS platform;
[Windows]: Windows platform;
[Perf]: performance improvements;
[CI]: CI/CD workflow;
[Misc]: something that doesn't belong to any category, such as version bump, reformatting;
[Bug]: bug fixes;
- Check out more tags in misc/prtags.json.
- When introducing a new tag, please update the list in
misc/prtags.jsonin the first PR with that tag, so that people can follow.
We do appreciate all kinds of contributions, yet we should not expose the title of every PR to end-users. Therefore the changelog will distinguish what the user should know from what the developers are doing. This is done by capitalizing PR tags:
- PRs with visible/notable features to the users should be marked
with tags starting with the first letter capitalized, e.g.
[CLI]. When releasing a new version, a script (
python/taichi/make_changelog.py) will generate a changelog with these changes (PR title) highlighted. Therefore it is important to make sure the end-users can understand what your PR does, based on your PR title.
- Other PRs (underlying development/intermediate implementation)
should use tags with everything in lowercase letters: e.g.
- Because of the way the release changelog is generated, there
should be at most one capitalized tag in a PR title to prevent
duplicate PR highlights. For example,
[GUI] [Mac] Support modifier keys(#1189) is a bad example, we should have used
[gui] [Mac] Support modifier keys in GUIinstead. Please capitalize the tag that is the most relevant to the PR.
The C++ part of Taichi is written in C++17, and the Python part in 3.6+. You can assume that C++17 and Python 3.6 features are always available.
Life of a Taichi kernel may worth checking out. It explains the whole compilation process.
See also Benchmarking and regression tests if your work involves IR optimization.
When creating a Taichi program using
ti.init(arch=desired_arch, **kwargs), pass in the following parameters
to make the Taichi compiler print out IR:
print_preprocessed=True: print results of the frontend Python AST transform. The resulting scripts will generate a Taichi Frontend AST when executed.
print_ir=True: print the Taichi IR transformation process of kernel (excluding accessors) compilation.
print_accessor_ir=True: print the IR transformation process of data accessors, which are special and simple kernels. (This is rarely used, unless you are debugging the compilation of data accessors.)
print_struct_llvm_ir=True: save the emitted LLVM IR by Taichi struct compilers.
print_kernel_llvm_ir=True: save the emitted LLVM IR by Taichi kernel compilers.
print_kernel_llvm_ir_optimized=True: save the optimized LLVM IR of each kernel.
print_kernel_nvptx=True: save the emitted NVPTX of each kernel (CUDA only).
Data accessors in Python-scope are implemented as special Taichi
kernels. For example,
x[1, 2, 3] = 3 will call the writing accessor
print(y) will call the reading accessor kernel
Key folders are:
(the following chart can be generated by
tree . -L 2)
.├── benchmarks # Performance benchmarks├── docs # Documentation├── examples # Examples├── external # External libraries├── misc # Random yet useful files├── python # Python frontend implementation│ ├── core # Loading & interacting with Taichi core│ ├── lang # Python-embbed Taichi language & syntax (major)│ ├── snode # Structure nodes│ ├── tools # Handy end-user tools│ └── misc # Miscellaneous utilities├── taichi # The core compiler implementation│ ├── analysis # Static analysis passes│ ├── backends # Device-dependent code generators/runtime environments│ ├── codegen # Code generation base classes│ ├── common # Common headers│ ├── gui # GUI system│ ├── inc # Small definition files to be included repeatedly│ ├── ir # Intermediate representation│ ├── jit # Just-In-Time compilation base classes│ ├── llvm # LLVM utilities│ ├── math # Math utilities│ ├── platform # Platform supports│ ├── program # Top-level constructs│ ├── python # C++/Python interfaces│ ├── runtime # LLVM runtime environments│ ├── struct # Struct compiler base classes│ ├── system # OS-related infrastructure│ ├── transforms # IR transform passes│ └── util # Miscellaneous utilities└── tests # Functional tests ├── cpp # Python tests (major) └── python # C++ tests
Tests should be added to
ti testto run all the tests.
ti test -vfor verbose outputs.
ti test -Cto run tests and record code coverage, see Code coverage for more information.
ti test -a <arch(s)>for testing against specified backend(s). e.g.
ti test -a cuda,metal.
ti test -na <arch(s)>for testing all architectures excluding some of them. e.g.
ti test -na opengl,x64.
ti test <filename(s)>to run specific tests in filenames. e.g.
ti test numpy_iowill run all tests in
ti test -cto run only the C++ tests. e.g.
ti test -c alg_simpwill run
ti test -k <key>to run tests that match the specified key. e.g.
ti test linalg -k "cross or diag"will run the
For more options, see
ti test -h.
For more details on how to write a test case, see Workflow for writing a Python test.
Documentation source files are under the
docs/ folder of the main Taichi repo.
An automatic service syncs the updated content with our documentation repo and deploys the documentation at the Taichi documentation site.
To set up a local server and preview your documentation edits in real time, see instructions for Local Development.
If you work on the language frontend (Python/C++ interface), to navigate around the code base, ffi-navigator allows you to jump from Python bindings to their definitions in C++, please follow their README to set up your editor.
Right now we are targeting CUDA 10. Since we use run-time loaded
CUDA driver APIs
which are relatively stable across CUDA versions, a compiled Taichi binary
should work for all CUDA versions >= 10. When upgrading CUDA version, the
external/cuda_libdevice/slim_libdevice.10.bc should also be
replaced with a newer version.
To generate the slimmed version of libdevice based on a full
libdevice.X.bc file from a CUDA installation, use:
ti task make_slim_libdevice [libdevice.X.bc file]