Taichi

- [Metal] [sparse] Experimental support for dynamic SNode (1039) (by **Ye Kuang**)
- [workflow] Test against multiple python versions (1048) (by **彭于斌**)
- [Lang] Support template arguments for ti.func (1043) (by **Kenneth Lozes**)
- [workflow] Not to run code format check when taichi-gardener is on (1047) (by **彭于斌**)
- [ir] [refactor] Deprecate loop_var (1032) (by **xumingkuan**)
- [Lang] Support passing numpy arrays to ti.Matrix constructor (1044) (by **Ye Kuang**)
- [doc] Use "build from source" instead of "build from scratch" (1040) (by **Rex**)
- [ir] [refactor] Remove super-word level vectorization (1041) (by **Yuanming Hu**)
- [refactor] Remove the global begin_stmt and end_stmt (1034) (by **Ye Kuang**)
- [workflow] Trigger format server when taichi-gardener is requested for review (1026) (by **彭于斌**)
- [workflow] Use GitHub Actions as Linux (cpu only) CI (1023) (by **彭于斌**)
- [doc] Fix a typo in snode.rst (1037) (by **Danni**)
- [metal] Initialize root ListManager's data only if there is sparse SNode (1028) (by **Ye Kuang**)
- [Lang][ir] "print" now support multiple scalar arguments (1029) (by **彭于斌**)
- [CLI] Add "ti example" command (1010) (by **Rex**)
- [revert] [workflow] workflows/stale.yml to detect stale issues and PRs (1035) (by **Yuanming Hu**)
- [metal] Fix SNode off-by-one problem (986) (by **Ye Kuang**)
- [doc] Improve dev_install (1030) (by **Yadi Cao**)
- [doc] Fix order of commands in dev_install (1033) (by **Linwei Shang**)
- [refactor] Refactor result buffer to allow return values and error codes coexist (1025) (by **Yuanming Hu**)
- [refactor] [ir] Deprecate the unused OffloadedResult (1027) (by **Ye Kuang**)
- [test] [sparse] Add a test case for bitmasked (1022) (by **Ye Kuang**)
- [refactor] Add a always_false class trait (1019) (by **Ye Kuang**)
- [opengl] use static gtmp buffer size to lower overhead (1014) (by **彭于斌**)
- [workflow] Add workflows/stale.yml to detect stale issues and PRs (1020) (by **彭于斌**)
- [misc] Remove debug info in release mode (1021) (by **Yuanming Hu**)
- [benchmark] Upgrade to Time Performance Regression Test (TPRT) (1002) (by **彭于斌**)
- [misc] Check code format using GitHub Actions/Workflows (957) (by **彭于斌**)

- [doc] Update install.rst and Miscellaneous (1009) (by **Yuanming Hu**)
- [Lang] Improve error message for Matrix/Vector accessors (1013) (by **Ye Kuang**)
- [doc] Minor improvements on basic concepts (997) (by **Xiao Zhai**)
- [Mac] [GUI] Fix bug due to View class name conflict (1012) (by **Ye Kuang**)
- [Example] Make cornell box more authentic (1006) (by **Ye Kuang**)
- [opengl] Fix unwanted "used.int64_t = true" in KernelReturnStmt (1003) (by **彭于斌**)
- [opengl][refactor] refactor stuff into one "SnodeInfo" for better furture sparse support (993) (by **彭于斌**)
- [refactor][Lang] Unify SNode and Tensor meta data accessor in both Taichi&Python-scope (971) (by **彭于斌**)
- [gui] Use np.clip(_, 0, 1) to fix win display error (1005) (by **彭于斌**)
- [doc] Update basic concepts (996) (by **Yuanming Hu**)
- [doc] Document list generation (990) (by **Yuanming Hu**)
- [async] Optimization stage 1 (994) (by **Yuanming Hu**)
- [doc] Update utilities.rst (989) (by **Yuanming Hu**)
- [benchmark] Upgrade "ti benchmark" to use no net repo (981) (by **彭于斌**)
- [opengl][refactor] RangeSizeEvaluator -> KernelParallelAttrib to store more infomation (985) (by **彭于斌**)
- [IR] Add an IR cloning pass (991) (by **xumingkuan**)
- [doc] Add install.rst for installation troubleshooting (980) (by **彭于斌**)
- [refactor] Rearrange taichi/common and taichi/util. taichi/core is removed. (979) (by **Yuanming Hu**)
- [ir] [refactor] Remove operand_bitmap from Stmt (987) (by **Yuanming Hu**)
- [doc] Update the "contributing" chapter (978) (by **Yuanming Hu**)
- [IR][refactor] Convert loop_var into LoopIndexStmt (953) (by **xumingkuan**)
- [doc] Fix missing language fields in code-blocks (983) (by **Xuanda Yang**)

- [doc] Minor updates in `hello.rst` (963) (by **Yuanming Hu**)
- [doc] Improve `hello.rst` (972) (by **Xiao Zhai**)
- [misc] Add a link to taichi_elements in README.md (974) (by **彭于斌**)
- [Bug] [opengl] [llvm] [metal] Fix floordiv overflow when `lhs * rhs` is large (970) (by **彭于斌**)
- [test] Size Performance Regression Tests (SPRT) (959) (by **彭于斌**)
- [Metal] Skip allocating Runtime::ListManager if no sparse SNode is used (976) (by **Ye Kuang**)
- [cuda] Improve kernel return value performance when unified memory is available (965) (by **Yuanming Hu**)
- [doc] Update `syntax.rst` and related sections (967) (by **Yuanming Hu**)
- [opengl] add TI_WITH_OPENGL env var to disable OpenGL (962) (by **彭于斌**)
- [opt] [cuda] Fix constant folding in multithreaded CUDA applications (954) (by **Yuanming Hu**)
- [ir][refactor] Avoid throwing exception in `replace_statements_with` (968) (by **xumingkuan**)
- [opengl] Use `compile_to_offloads` for IR lowering (951) (by **彭于斌**)
- [Doc] fix typo in syntax_sugars.po (960) (by **Danni**)
- [refactor][ir] Simplify ir.h to reduce compile-time (934) (by **彭于斌**)
- [lang] [refactor] deprecate boardcast_if_scalar, all use binary and unary (943) (by **彭于斌**)
- [doc] Improve `hello.rst` (955) (by **Yuanming Hu**)
- [metal] Set labels on the command buffer/encoder (950) (by **Ye Kuang**)
- [ir] Remove BasicStmtVisitor::current_struct_for (952) (by **xumingkuan**)
- [misc] README.md use shields.io to show latest release (947) (by **彭于斌**)
- [Lang][IR][refactor] Refactor SNode and support coordinate offsets (945) (by **Yuanming Hu**)

- [Doc] Add documentions for layout (900) (by **彭于斌**)
- [IR] Use JIT compilation/evaluation for systematic constant folding (839) (by **彭于斌**)
- [doc] Update doc for kernel return in 930 (942) (by **彭于斌**)
- [Lang] `ti.sqr(x)` is now deprecated: please use `x ** 2` instead (937) (by **Yuanming Hu**)
- [ir][refactor] Deprecate `ArgStoreStmt` (both frontend and CHI) (936) (by **Ye Kuang**)
- [metal] Support `KernelReturnStmt` (930) (by **Ye Kuang**)
- [Misc] Remove dependency on glibc 2.27 and improve portability (931) (by **Yuanming Hu**)
- [Lang] [IR] Kernel scalar `return` support (`ArgStoreStmt` -> `KernelReturnStmt`) (917) (by **彭于斌**)
- [Example] Add `waterwave.py` (792) (by **彭于斌**)

Highlights:
- **Miscellaneous**
- Add `ti.core.toggle_advanced_optimization(True/False)` (927) (by **Yuanming Hu**)

Full changelog:
- [doc] Non-Ubuntu Linux users are suggested to build clang-8 from scratch (867) (by **彭于斌**)
- [Misc] Add `ti.core.toggle_advanced_optimization(True/False)` (927) (by **Yuanming Hu**)
- [ir][refactor] Move legacy frontend constructs to frontend.h/cpp (924) (by **Ye Kuang**)
- [misc] Enforce format (922) (by **Taichi Gardener**)
- [ir][refactor] Move all Expression subclasses to `frontend_ir.h` (919) (by **Ye Kuang**)

Highlights:
- **Automatic differentiation**
- Fix CUDA data layout and stack alignment (918) (by **Yuanming Hu**)
- **CUDA backend**
- Fix CUDA data layout and stack alignment (918) (by **Yuanming Hu**)
- **Examples**
- Add `example/bitmasked.py` (905) (by **彭于斌**)
- **GUI**
- Better event filtering system (801) (by **彭于斌**)
- **Language and syntax**
- Scalar math functions can now be applied element-wisely to vectors/matrices (891) (by **彭于斌**)

Full changelog:
- [ir][refactor] Move all frontend stmts to `frontend_ir.h` (916) (by **Ye Kuang**)
- [CUDA] [AutoDiff] Fix CUDA data layout and stack alignment (918) (by **Yuanming Hu**)
- [Example] Add example/bitmasked.py (905) (by **彭于斌**)
- [opengl] [bug] Move GLSLRuntime into a separate buffer, fix ti.random() bug on NVIDIA (912) (by **彭于斌**)
- [ir][refactor] First step to move Frontend IR to its own file (914) (by **Ye Kuang**)
- [async] Avoid unnecessary list generations and activations (913) (by **Yuanming Hu**)
- [Lang] Scalar math functions can now be applied element-wisely to vectors/matrices (891) (by **彭于斌**)
- [ir] Deprecate `FrontendAtomicStmt` (907) (by **Ye Kuang**)
- [ir] [refactor] Remove the global `current_block` (908) (by **Ye Kuang**)
- [ir][refactor] Pass a context object to `Expression::flatten()` (901) (by **Ye Kuang**)
- [test] Add an argument -r to rerun failed test (904) (by **彭于斌**)
- [GUI] Better event filtering system (801) (by **彭于斌**)