Taichi

Highlights:
- **Bug fixes**
- Fix all potential matrix SSA violation by using element_wise_write_binary (1424) (by **彭于斌**)
- **CUDA backend**
- Improve random number generator performance (1419) (by **Yuanming Hu**)
- **Docker**
- Update the Dockerfile to use up-to-date instructions for Ubuntu (1385) (by **Chengchen(Rex) Wang**)
- **Error messages**
- Raise an warning when a Taichi matrix have > 32 entries (1401) (by **彭于斌**)
- Show pretty & intuitive stack traceback when ti.enable_excepthook() used (1405) (by **彭于斌**)
- **GUI**
- Get images from the current GUI using gui.get_image() (1422) (by **Xudong Feng**)
- Support mouse wheel event on Linux/X11 (1411) (by **彭于斌**)
- Support mouse wheel event on Mac Cocoa (1418) (by **Ye Kuang**)
- Support mouse wheel event on Win32 (1382) (by **JYLeeLYJ**)
- **Intermediate representation**
- Block local storage for struct-for's on CUDA (1394) (by **Yuanming Hu**)
- **Language and syntax**
- Add ti.static_assert for compile-time assertations (1344) (by **彭于斌**)
- **Metal backend**
- Use managed storage mode to improve performance (1415) (by **Ye Kuang**)
- **IR optimization passes**
- Better aliasing analysis for dead store elimination (1432) (by **xumingkuan**)
- **Performance improvements**
- Support TLS for GlobalTemporaryStmt (1423) (by **Ye Kuang**)

Full changelog:
- [GUI] Get images from the current GUI using gui.get_image() (1422) (by **Xudong Feng**)
- [cuda] [bug] Fix CUDA garbage collection grid dim (1438) (by **Yuanming Hu**)
- [misc] ActionRecorder (Stage I) (1428) (by **Yuanming Hu**)
- [Bug] [lang] [std] Fix all potential matrix SSA violation by using element_wise_write_binary (1424) (by **彭于斌**)
- [Opt] [bug] Better aliasing analysis for dead store elimination (1432) (by **xumingkuan**)
- [metal] Pass kernel name and is_evalutator to the runtime (1430) (by **Ye Kuang**)
- [Error] Raise an warning when a Taichi matrix have > 32 entries (1401) (by **彭于斌**)
- [llvm] Separate BLS/TLS and refactor loop code generation (1425) (by **Yuanming Hu**)
- [Metal] Use managed storage mode to improve performance (1415) (by **Ye Kuang**)
- [Perf] Support TLS for GlobalTemporaryStmt (1423) (by **Ye Kuang**)
- [Error] Show pretty & intuitive stack traceback when ti.enable_excepthook() used (1405) (by **彭于斌**)
- [error] Instruct user to use static range when matrix accessed with non constant index (1420) (by **彭于斌**)
- [CUDA] Improve random number generator performance (1419) (by **Yuanming Hu**)
- [GUI] [linux] Support mouse wheel event on Linux/X11 (1411) (by **彭于斌**)
- [GUI] Support mouse wheel event on Mac Cocoa (1418) (by **Ye Kuang**)
- [error] Fix wrong error message when using vector as if condition (1417) (by **彭于斌**)
- [bug] Fix test_fibonacci (1414) (by **Ye Kuang**)
- [test] [std] Add matrix SSA violation regression test (1412) (by **彭于斌**)
- [GUI] Support mouse wheel event on Win32 (1382) (by **JYLeeLYJ**)
- [opt] [refactor] Move advanced optimization toggle to "ti.cfg.advanced_optimization" (1403) (by **彭于斌**)
- [Lang] Add ti.static_assert for compile-time assertations (1344) (by **彭于斌**)
- [IR] Block local storage for struct-for's on CUDA (1394) (by **Yuanming Hu**)
- [Docker] Update the Dockerfile to use up-to-date instructions for Ubuntu (1385) (by **Chengchen(Rex) Wang**)
- [llvm] Use LLVM 10 for AppVeyor and GitHub actions (1402) (by **Yuanming Hu**)
- [opt] Flatten if(0) and if(1) (1393) (by **xumingkuan**)
- [cc] Add struct compiler to the experimental C backend (1354) (by **彭于斌**)
- [workflow] Fix PR title checker "fix fatal: bad revision 'master'" in release PR (1399) (by **彭于斌**)

Highlights:
- **Bug fixes**
- Fix compilation crash when there's a cross-offload global atomic operation (1392) (by **xumingkuan**)
- Fix ti.func not capturing closure variables (1380) (by **彭于斌**)
- **CUDA backend**
- Taichi now supports CUDA 11 (1395) (by **Yuanming Hu**)
- **Language and syntax**
- Deprecate x.data_type() and use x.dtype instead (1374) (by **彭于斌**)
- **IR optimization passes**
- Do not flatten if's by default (1372) (by **xumingkuan**)
- **Performance improvements**
- Support TLS and SIMD group reduction for range-for kernels (1358) (by **Ye Kuang**)

Full changelog:
- [Bug] [ir] Fix compilation crash when there's a cross-offload global atomic operation (1392) (by **xumingkuan**)
- [lang] [bug] Fix Matrix.diag (remove unwanted truncation to int) (1397) (by **Yuanming Hu**)
- [ir] Fix ir_printer now that print() supports end (1350) (by **Ye Kuang**)
- [Bug] [lang] Fix ti.func not capturing closure variables (1380) (by **彭于斌**)
- [cli] Use "ti task" for run task (legacy), and "ti run" to run script (1391) (by **彭于斌**)
- [ir] Remove a temporary "fix_block_parents" (1352) (by **xumingkuan**)
- [CUDA] Taichi now supports CUDA 11 (1395) (by **Yuanming Hu**)
- [bug] [refactor] Fix error when ti.init() not called by deprecating Expr.layout_materialized (1347) (by **彭于斌**)
- [refactor] [Lang] Deprecate x.data_type() and use x.dtype instead (1374) (by **彭于斌**)
- [lang] "ti.chain_compare" now can return python-scope constants (1356) (by **彭于斌**)
- [refactor] Move c_quoted into taichi/utils/ (1376) (by **Ye Kuang**)
- [lang] [bug] Add ti.pyfunc for functions that work in both Taichi and Python-scope, fix matrix methods (1338) (by **彭于斌**)
- [bug] Fix master due to compilation error (1375) (by **Ye Kuang**)
- [llvm] Further improve LLVM 10 compatibility by using RTLD_DEEPBIND (1355) (by **彭于斌**)
- [workflow] Fix GitHub workflows (1370) (by **Yuanming Hu**)
- [Opt] Do not flatten if's by default (1372) (by **xumingkuan**)
- [bug] [opt] Fix CFG ignoring local atomics after lower_access (1371) (by **xumingkuan**)
- [misc] [gui] Resolve deprecation warning (img.shape) (1369) (by **Hojun Yoon**)
- [lang] Raise an error when struct-for indices number mismatch (1357) (by **彭于斌**)
- [Perf] [metal] Support TLS and SIMD group reduction for range-for kernels (1358) (by **Ye Kuang**)

Highlights:
- **IPython and other shells**
- Support inline output display in Jupyter GUI (1331) (by **彭于斌**)
- **IR optimization passes**
- Replace "simplify" with "full_simplify" in "Simplified I" (1353) (by **xumingkuan**)

Full changelog:
- [misc] Format the C backend (1364) (by **Taichi Gardener**)
- [misc] Exclude C backend by default to fix Linux builds (1362) (by **Yuanming Hu**)
- [cc] Set up the experimental C language backend (1348) (by **彭于斌**)
- [Opt] Replace "simplify" with "full_simplify" in "Simplified I" (1353) (by **xumingkuan**)
- [doc] Update compilation.rst (1351) (by **Yuanming Hu**)
- [IPython] [gui] Support inline output display in Jupyter GUI (1331) (by **彭于斌**)
- [refactor] [metal] Add a TaichiKernelAttribs struct (1341) (by **Ye Kuang**)

Highlights:
- **Bug fixes**
- Use RTLD_LOCAL to prevent LLVM symbol conflict with GLX (1326) (by **彭于斌**)
- **Documentation**
- Minor fix for global settings (1328) (by **Danni**)
- **GUI**
- Fix issue with triangles not showing up when they are drawn clockwisely (1321) (by **Xudong Feng**)
- **IPython and other shells**
- Make OpenGL kernel print work in IPython & IDLE (1303) (by **彭于斌**)
- Source inspection dispatcher for better IDLE compatibility (1222) (by **彭于斌**)
- **Language and syntax**
- Deprecate x.shape() and x.dim(), use x.shape instead (1318) (by **彭于斌**)
- **Metal backend**
- Add codegen/runtime support for print() (1310) (by **Ye Kuang**)
- **OpenGL backend**
- Basic support for dynamic SNode (1256) (by **彭于斌**)
- **IR optimization passes**
- Dead store and stack-related operation elimination by control-flow graph (1324) (by **xumingkuan**)
- **Performance improvements**
- Thread local storage for range-for reductions on GPUs (1336) (by **Yuanming Hu**)
- **Sparse computation**
- Add ti.activate support (1334) (by **彭于斌**)

Full changelog:
- [Sparse] [lang] Add ti.activate support (1334) (by **彭于斌**)
- [IPython] [opengl] Make OpenGL kernel print work in IPython & IDLE (1303) (by **彭于斌**)
- [linux] Remove glibc2.27 dependency (log2fglibc2.27) (1342) (by **Yuanming Hu**)
- [lang] Return None when parent() exceeds its maximum depth (1319) (by **Ye Kuang**)
- [Perf] Thread local storage for range-for reductions on GPUs (1336) (by **Yuanming Hu**)
- [Opt] Dead store and stack-related operation elimination by control-flow graph (1324) (by **xumingkuan**)
- [Metal] Add codegen/runtime support for print() (1310) (by **Ye Kuang**)
- [Lang] [refactor] Deprecate x.shape() and x.dim(), use x.shape instead (1318) (by **彭于斌**)
- [Doc]Minor fix for global settings (1328) (by **Danni**)
- [lang] Deprecate ti.raw_pow (1330) (by **彭于斌**)
- [OpenGL] [sparse] Basic support for dynamic SNode (1256) (by **彭于斌**)
- [Bug] [linux] [opengl] Use RTLD_LOCAL to prevent LLVM symbol conflict with GLX (1326) (by **彭于斌**)
- [doc] Fix some typos in our document export_results.rst (1312) (by **Xudong Feng**)
- [misc] fix a bug in util.py (1327) (by **Xudong Feng**)
- [doc] Add Taichi THREE to documentation (1309) (by **彭于斌**)
- [GUI] Fix issue with triangles not showing up when they are drawn clockwisely (1321) (by **Xudong Feng**)
- [misc] Fix compilation warning (1320) (by **Ye Kuang**)
- [IPython] Source inspection dispatcher for better IDLE compatibility (1222) (by **彭于斌**)

Highlights:
- **Bug fixes**
- Fix compilation crash when there is a container statement after an unconditional continue (1299) (by **xumingkuan**)
- **CUDA backend**
- Fix on-demand memory pool on certain GPUs (1314) (by **Yuanming Hu**)
- **Intermediate representation**
- Replace "OffsetAndExtractBitsStmt" with "BitExtractStmt" (1306) (by **xumingkuan**)
- **Language and syntax**
- Support sep and end in print() (1311) (by **Ye Kuang**)
- Support Python-scope scalar functions / matrix operations, e.g. ti.sqrt(2) (1188) (by **彭于斌**)
- **Miscellaneous**
- Postpone backend detection to prevent possible compatibility issues (1273) (by **彭于斌**)
- **IR optimization passes**
- Move unreachable code elimination to a separate pass (1315) (by **xumingkuan**)
- Constant folding for BitExtractStmt (1307) (by **xumingkuan**)
- Remove exceptions from lower_access pass (1292) (by **Xuanda Yang**)
- **Performance improvements**
- Thread local storage for range-for reductions on CPUs (1296) (by **Yuanming Hu**)
- **Standard library**
- Add ti.rsqrt() and ti.Vector.norm_inv() (1293) (by **彭于斌**)

Full changelog:
- [cuda] Support numpy and torch tensors with zeros in shapes (e.g., (5, 0, 5)) (1305) (by **Yuanming Hu**)
- [refactor] Rename the file created in 1315 (1316) (by **xumingkuan**)
- [Opt] [refactor] Move unreachable code elimination to a separate pass (1315) (by **xumingkuan**)
- [CUDA] Fix on-demand memory pool on certain GPUs (1314) (by **Yuanming Hu**)
- [Opt] Constant folding for BitExtractStmt (1307) (by **xumingkuan**)
- [lang] [test] Improve code coverage in SNode (1214) (by **彭于斌**)
- [Lang] Support sep and end in print() (1311) (by **Ye Kuang**)
- [metal] Add kernel side util to support print() (1301) (by **Ye Kuang**)
- [Misc] Postpone backend detection to prevent possible compatibility issues (1273) (by **彭于斌**)
- [IR] [refactor] Replace "OffsetAndExtractBitsStmt" with "BitExtractStmt" (1306) (by **xumingkuan**)
- [Bug] [opt] Fix compilation crash when there is a container statement after an unconditional continue (1299) (by **xumingkuan**)
- [ir] [refactor] Simplify the "re_id" pass (1304) (by **xumingkuan**)
- [Perf] Thread local storage for range-for reductions on CPUs (1296) (by **Yuanming Hu**)
- [bug] [std] Fix matrix print shape in Taichi-scope (1300) (by **彭于斌**)
- [metal] [autodiff] Fix StackLoadTopStmt codegen in Metal (1298) (by **Ye Kuang**)
- [Lang] [refactor] Support Python-scope scalar functions / matrix operations, e.g. ti.sqrt(2) (1188) (by **彭于斌**)
- [Std] [lang] Add ti.rsqrt() and ti.Vector.norm_inv() (1293) (by **彭于斌**)
- [Opt] [ir] [refactor] Remove exceptions from lower_access pass (1292) (by **Xuanda Yang**)
- [misc] Show LLVM version on startup (1294) (by **FantasyVR**)

Highlights:
- **Automatic differentiation**
- Refactor AutoDiff system and support for loops that carry mutable states (1285) (by **Yuanming Hu**)
- **Bug fixes**
- Fix a bug causing gradients to be NaNs (1284) (by **xumingkuan**)
- **Command line interface**
- Toggle torch import by env var: TI_ENABLE_TORCH (1268) (by **彭于斌**)
- **CUDA backend**
- Support "ti.cache_read_only" (1276) (by **Yuanming Hu**)
- **Examples**
- Improve examples/odop_solar.py visual & comments (1253) (by **彭于斌**)
- **GUI**
- Fix "gui.set_image" not accept multi-channel scalar tensors (1264) (by **彭于斌**)
- **Metal backend**
- Add AD stack to support the local mutables when using AutoDiff (1257) (by **Ye Kuang**)
- **IR optimization passes**
- Remove exceptions from demote_atomics pass (1272) (by **Xuanda Yang**)
- Store-to-load forwarding with Control-flow graph (1248) (by **xumingkuan**)
- Remove exceptions from DIE pass (1262) (by **Xuanda Yang**)

Full changelog:
- [bug] Fix stochastic failure of test_loop_grad on Windows (1291) (by **Yuanming Hu**)
- [AutoDiff] Refactor AutoDiff system and support for loops that carry mutable states (1285) (by **Yuanming Hu**)
- [Bug] [opt] Fix a bug causing gradients to be NaNs (1284) (by **xumingkuan**)
- [opt] Fix CFGNode::store_to_load_forwarding data type (1283) (by **Yuanming Hu**)
- [Opt] [ir] [refactor] Remove exceptions from demote_atomics pass (1272) (by **Xuanda Yang**)
- [Example] Improve examples/odop_solar.py visual & comments (1253) (by **彭于斌**)
- [lang] [test] Improve code coverage in Matrix (1275) (by **彭于斌**)
- [opt] Do not consider each GlobalPtrStmt as a data source in store forwarding (1279) (by **xumingkuan**)
- [CUDA] Support "ti.cache_read_only" (1276) (by **Yuanming Hu**)
- [ir] Make pass names appear in correct positions when print_ir=True (1277) (by **xumingkuan**)
- [cuda] [bug] Fix CUDA runtime crash (1271) (by **Yuanming Hu**)
- [CLI] Toggle torch import by env var: TI_ENABLE_TORCH (1268) (by **彭于斌**)
- [Opt] Store-to-load forwarding with Control-flow graph (1248) (by **xumingkuan**)
- [perf] [opt] Better weaken_access pass for sparse cases (1270) (by **Yuanming Hu**)
- [Opt] [ir] [refactor] Remove exceptions from DIE pass (1262) (by **Xuanda Yang**)
- [Metal] Add AD stack to support the local mutables when using AutoDiff (1257) (by **Ye Kuang**)
- [GUI] [bug] Fix "gui.set_image" not accept multi-channel scalar tensors (1264) (by **彭于斌**)