Taichi

Highlights:
- **Bug fixes**
- Fix OffsetAndExtractBitsStmt optimization and improve documentation on virtual/physical indices (1259) (by **Yuanming Hu**)
- Fix image I/O for channels = 1 and improve test coverage (unrevert) (1242) (by **彭于斌**)
- Fix tuple assignment behavior in Taichi-scope (1247) (by **彭于斌**)
- **Documentation**
- Standardize versioning and release workflow (1220) (by **Yuanming Hu**)
- **Language and syntax**
- Support vector unpacking (e.g., "a, b = ti.Vector([1, 2])") (1252) (by **彭于斌**)
- **IR optimization passes**
- Remove exceptions from IR check_out_of_bound and constant_fold (1251) (by **Xuanda Yang**)

Full changelog:
- [workflow] Improve PR title checker for the release tag (1244) (by **彭于斌**)
- [Lang] Support vector unpacking (e.g., "a, b = ti.Vector([1, 2])") (1252) (by **彭于斌**)
- [perf] Refactor kernel profiler (1261) (by **Yuanming Hu**)
- [Bug] [opt] [doc] Fix OffsetAndExtractBitsStmt optimization and improve documentation on virtual/physical indices (1259) (by **Yuanming Hu**)
- [perf] Improve dynamic SNode performance (stage 3) (1238) (by **xumingkuan**)
- [misc] Add auto-profiling to IR passes (1255) (by **xumingkuan**)
- [doc] Remove changelog link from readme (1209) (by **Chengchen(Rex) Wang**)
- [Opt] [ir] [refactor] Remove exceptions from IR check_out_of_bound and constant_fold (1251) (by **Xuanda Yang**)
- [Bug] [misc] Fix image I/O for channels = 1 and improve test coverage (unrevert) (1242) (by **彭于斌**)
- [Bug] [lang] Fix tuple assignment behavior in Taichi-scope (1247) (by **彭于斌**)
- [ir] Set root block kernel after cloning (1245) (by **Ye Kuang**)
- [cli] Add "ti dist" command to test in release mode (1227) (by **彭于斌**)
- [Doc] Standardize versioning and release workflow (1220) (by **Yuanming Hu**)
- [test] Add coverage threshold to make codecov not fail so easily (1246) (by **彭于斌**)
- [bug] [lang] Use functools.wraps for non-classfunc too (1233) (by **彭于斌**)

Highlights:
- **GUI**
- Support modifier keys like Shift, Ctrl, etc (1189) (by **Ye Kuang**)
- **Intermediate representation**
- Move "lower_access" to after "offload" (1194) (by **xumingkuan**)
- **Language and syntax**
- ti.Matrix initializers (1107) (by **Peiyuan Liao**)
- **LLVM backend (CPU and CUDA)**
- Support LLVM 10 (1200) (by **Yuanming Hu**)
- **Mac OS X**
- Support modifier keys like Shift, Ctrl, etc (1189) (by **Ye Kuang**)
- **OpenGL backend**
- support print 1 scalar in OpenGL kernels (1166) (by **彭于斌**)

Full changelog:
- [test] Ensure CUDA tests use < 1 GB memory (1213) (by **Yuanming Hu**)
- [cuda] Add print_kernel_nvptx to CompileConfig (1211) (by **Yuanming Hu**)
- [llvm] [cuda] Improve LLVM 8 compatibility (1210) (by **Yuanming Hu**)
- [bug] Fix matrix operations to use numpy only in Python scope (1208) (by **Ye Kuang**)
- [test] No warning on deprecation test & add test_maxmin (1207) (by **彭于斌**)
- [doc] [workflow] Update hello and matrix section of the docs and add a workflow to check doc builds (1157) (by **Chengchen(Rex) Wang**)
- [llvm] [opt] CSE for LoopIndexStmt (1203) (by **Yuanming Hu**)
- [LLVM] Support LLVM 10 (1200) (by **Yuanming Hu**)
- [test] Setup python coverage test (1196) (by **彭于斌**)
- [IR] Move "lower_access" to after "offload" (1194) (by **xumingkuan**)
- [misc] Remove usage of deprecated functions in benchmarks (1193) (by **Yuanming Hu**)
- [test] Let pytest-rerunfailures pytest-xdist to be hard dependences (1187) (by **彭于斌**)
- [GUI] [Mac] Support modifier keys like Shift, Ctrl, etc (1189) (by **Ye Kuang**)
- [OpenGL] support print 1 scalar in OpenGL kernels (1166) (by **彭于斌**)
- [Lang] [refactor] ti.Matrix initializers (1107) (by **Peiyuan Liao**)

Highlights:
- **Bug fixes**
- Fix ti.sqrt/exp/log error with an integral operand (1179) (by **xumingkuan**)
- Fix AMD+OpenGL to_numpy behavior (thank Eydcao for testing) (1160) (by **彭于斌**)
- Fix keyboard event loss problem on specific Win OS version (1162) (by **JYLeeLYJ**)
- **Command line interface**
- Add "ti changelog" command to print changelog of current version (1153) (by **彭于斌**)
- Improve the "ti" command (1085) (by **Chengchen(Rex) Wang**)
- Support running examples with python file extension (1098) (by **Xuanda Yang**)
- **Documentation**
- Add export_result section on how to export images and videos (1151) (by **Xudong Feng**)
- **GUI**
- Support ti.GUI.EXIT on Mac (1171) (by **Ye Kuang**)
- Add ti.GUI.EXIT event to close a window (1152) (by **彭于斌**)
- Use Taichi kernels instead of NumPy operations to reduce GUI.set_image overhead (1132) (by **彭于斌**)
- **Intermediate representation**
- Fix bound checks with coordinate offsets (1143) (by **Xuanda Yang**)
- Add coordinate offset argument for ti.var/Vector/Matrix (1102) (by **Xudong Feng**)
- **Language and syntax**
- Support Python-scope matrix/vector operations (1051) (by **Chengchen(Rex) Wang**)
- Fix bound checks with coordinate offsets (1143) (by **Xuanda Yang**)
- shows an error if not called from correct Taichi/Python-scope (1121) (by **彭于斌**)
- support v.x/v.y/v.z/v.w for easy Vector subscript (1133) (by **彭于斌**)
- Add coordinate offset argument for ti.var/Vector/Matrix (1102) (by **Xudong Feng**)
- Add Matrix.dim()/shape()/data_type() support (1086) (by **彭于斌**)
- **IR optimization passes**
- Improve strength reduction optimization for "pow" (1170) (by **xumingkuan**)
- **Performance improvements**
- Improve dynamic SNode performance (1182) (by **Yuanming Hu**)

Full changelog:
- [Perf] Improve dynamic SNode performance (1182) (by **Yuanming Hu**)
- [Bug] [ir] Fix ti.sqrt/exp/log error with an integral operand (1179) (by **xumingkuan**)
- [Opt] Improve strength reduction optimization for "pow" (1170) (by **xumingkuan**)
- [cli] Sort video input frames (1177) (by **Yuanming Hu**)
- [Bug] [opengl] Fix AMD+OpenGL to_numpy behavior (thank Eydcao for testing) (1160) (by **彭于斌**)
- [misc] Add some links to README.md (1165) (by **彭于斌**)
- [Doc] Add export_result section on how to export images and videos (1151) (by **Xudong Feng**)
- [refactor] Move log2int into arithmatic.h (1155) (by **Ye Kuang**)
- [GUI] Support ti.GUI.EXIT on Mac (1171) (by **Ye Kuang**)
- [misc] Generate changelog before trying to run build.py. (1169) (by **Chengchen(Rex) Wang**)
- [GUI] Add ti.GUI.EXIT event to close a window (1152) (by **彭于斌**)
- [gui] [Bug] Fix keyboard event loss problem on specific Win OS version (1162) (by **JYLeeLYJ**)
- [GUI] Use Taichi kernels instead of NumPy operations to reduce GUI.set_image overhead (1132) (by **彭于斌**)
- [doc] Better coordinate offset documentation (1148) (by **彭于斌**)
- [mac] [misc] Fix Travis CI: no <filesystem>, use <unistd.h> instead (1161) (by **彭于斌**)
- [example] [refactor] Rename some old examples to avoid confusing people (1149) (by **彭于斌**)
- [CLI] Add "ti changelog" command to print changelog of current version (1153) (by **彭于斌**)
- [llvm] Cache llvm runtime bitcode to reduce start up time in dev mode (1144) (by **彭于斌**)
- [Lang] Support Python-scope matrix/vector operations (1051) (by **Chengchen(Rex) Wang**)
- [metal] Add APIs to list all the available Metal devices (1139) (by **Ye Kuang**)
- [Lang] [IR] Fix bound checks with coordinate offsets (1143) (by **Xuanda Yang**)
- Fix "unclosed file" in "ti regression" (1147) (by **xumingkuan**)
- [bug] [gui] Use lower case for Win32 key events to unify with X11 (1140) (by **彭于斌**)
- [opt] [refactor] [bug] Avoid throwing exceptions in whole_kernel_cse and fix a bug (1131) (by **xumingkuan**)
- [Lang] [refactor] shows an error if not called from correct Taichi/Python-scope (1121) (by **彭于斌**)
- [Lang] support v.x/v.y/v.z/v.w for easy Vector subscript (1133) (by **彭于斌**)
- [test] [refactor] Fix test_element_wise.py long time (1120) (by **彭于斌**)
- [misc] tell users to check troubleshooting page when error occurred (1127) (by **彭于斌**)
- [misc] Update links in README.md (1129) (by **Zlatan Vasović**)
- [refactor] [metal] Rename some variables from args to ctx (1111) (by **Ye Kuang**)
- [ir] [refactor] Add constructor TypedConstant(DataType, T) (1104) (by **xumingkuan**)
- [misc] [test] Fix matrix initialization (1114) (by **Yuanming Hu**)
- [CLI] [refactor] Improve the "ti" command (1085) (by **Chengchen(Rex) Wang**)
- [Lang] [IR] Add coordinate offset argument for ti.var/Vector/Matrix (1102) (by **Xudong Feng**)
- [Lang] Add Matrix.dim()/shape()/data_type() support (1086) (by **彭于斌**)
- [doc] Add 64-bit Python troubleshooting (1101) (by **彭于斌**)
- [gui] Fix memory leak as circles were not cleared (1112) (by **Ye Kuang**)
- [opt] Add a DelayedIRModifier class (1103) (by **xumingkuan**)
- [opt] Improve the whole kernel CSE pass (1082) (by **xumingkuan**)
- [CLI] [example] Support running examples with python file extension (1098) (by **Xuanda Yang**)

Highlights:
- **GUI**
- Support drawing text on canvas (1070) (by **彭于斌**)
- **Language and syntax**
- Standardize math API (stage 1) (1091) (by **彭于斌**)
- ti.cross now supports 2D vectors (1068) (by **Yadi Cao**)
- deprecate "as_vector=True" (1046) (by **彭于斌**)
- Add any()/all() functions for Matrix, move casting ops to common_ops (1064) (by **Kenneth Lozes**)
- "print()" now support strings and matrices/vectors (1038) (by **彭于斌**)
- **IR optimization passes**
- Build a control-flow graph for optimization (932) (by **xumingkuan**)
- Add strength reduction optimizations (1065) (by **xumingkuan**)
- Avoid throwing exceptions in alg_simp and let it support more types (1060) (by **xumingkuan**)

Full changelog:
- [misc] Set gdb trigger to off by default (1093) (by **Yuanming Hu**)
- [test] [refactor] Deprecate ti.layout in test cases (1092) (by **Chengchen(Rex) Wang**)
- [Lang] [refactor] Standardize math API (stage 1) (1091) (by **彭于斌**)
- [lang] [refactor] Move atomic operations/augassign to ops.py (1062) (by **彭于斌**)
- [GUI] Support drawing text on canvas (1070) (by **彭于斌**)
- [cuda] [test] Improve portability and remove GC tests on CUDA for now (1090) (by **Yuanming Hu**)
- [bug] [ir] Fix Block::replace_with segment faults when stmts.size() == 0 (1072) (by **彭于斌**)
- [bug] [test] Fix CUDA segmentation fault when printing more than 32 entries (1089) (by **彭于斌**)
- [Opt] Build a control-flow graph for optimization (932) (by **xumingkuan**)
- [llvm] [sparse] Fix a memory leak bug in GC's free list on CPU (1079) (by **Ye Kuang**)
- [misc] Add a script to add copyright notices (1031) (by **Leedehai**)
- [opengl] Make the comparison result -1 for true (1080) (by **彭于斌**)
- [misc] Fix import warnings when using collections module (1084) (by **Ye Kuang**)
- [metal] Make the comparison result -1 for true (1078) (by **Ye Kuang**)
- [Lang] ti.cross now supports 2D vectors (1068) (by **Yadi Cao**)
- [misc] Improve Windows core loading message (1075) (by **Yuanming Hu**)
- [doc] Document TaichiCon (1052) (by **Yuanming Hu**)
- [doc] Fix sample code format (1073) (by **Yuanming Hu**)
- [Lang][refactor] deprecate "as_vector=True" (1046) (by **彭于斌**)
- [doc] Emphasize some ideas on how to communicate effectively (1061) (by **Ye Kuang**)
- [Opt] Add strength reduction optimizations (1065) (by **xumingkuan**)
- [Lang] Add any()/all() functions for Matrix, move casting ops to common_ops (1064) (by **Kenneth Lozes**)
- [refactor] [ir] IR system refactorings (1058) (by **Xuanda Yang**)
- [lang] [refactor] Move logical operations to ops.py (1054) (by **彭于斌**)
- [Opt] [refactor] Avoid throwing exceptions in alg_simp and let it support more types (1060) (by **xumingkuan**)
- [Lang][ir] "print()" now support strings and matrices/vectors (1038) (by **彭于斌**)
- [metal] Remove global constant def section (1056) (by **Ye Kuang**)

- [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**)