[doc] [workflow] Update hello and matrix section of the docs and add a workflow to check doc builds

.github/workflows/docs.yml

@@ -0,0 +1,22 @@
+name: Documentation Build Check
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+    paths:
+    - "docs/**"
+
+jobs:
+  check_docs_build:
+    name: Check Docs Build
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-python@v2
+      with:
+        python-version: 3.7
+    - name: Install dependencies
+      run: |
+        pip install sphinx sphinx_rtd_theme
+    - name: Try to build docs
+      run: |
+        cd docs && sphinx-build -b html . build

docs/cli_utilities.rst

@@ -0,0 +1,19 @@
+Command line utilities
+======================
+
+A successful installation of Taichi should add a CLI (Command-Line Interface) to your system,
+which is helpful to perform several rountine tasks quickly. To invoke the CLI, please
+run ``ti`` or ``python3 -m taichi``.
+
+Examples
+--------
+Taichi provides a set of bundled examples. You could run ``ti example -h`` to print the help
+message and get a list of available example names. For instance, to run the basic `fractal`
+example, try: ``ti example fractal`` from your shell. (``ti example fractal.py`` should also
+work)
+
+
+Changelog
+---------
+Sometimes it's convenient to view the changelog of the current version of Taichi, to do so from
+your shell, you could run ``ti changelog``.

docs/dev_install.rst

@@ -108,7 +108,7 @@ Prebuilt LLVM for Windows CI
 
   cmake .. -G"Visual Studio 15 2017 Win64"  -DLLVM_ENABLE_RTTI:BOOL=ON -DBUILD_SHARED_LIBS:BOOL=OFF -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="X86;NVPTX" -DLLVM_ENABLE_ASSERTIONS=ON -Thost=x64 -DLLVM_BUILD_TESTS:BOOL=OFF -DCMAKE_INSTALL_PREFIX=installed
 
-Then use Visual Studio to build. After building the ``INSTALL`` project (under folder "CMakePredefinedTargets"). After build completes, find your LLVM binaries/headers in `build/include`.
+Then use Visual Studio (Build Tools) to build, after which build the ``INSTALL`` project (under folder "CMakePredefinedTargets"). Once the build completes, find your LLVM binaries/headers in `build/include`.
 
 Troubleshooting
 ---------------

docs/hello.rst

@@ -3,7 +3,7 @@ Hello, world!
 
 We introduce the Taichi programming language through a very basic `fractal` example.
 
-Running the Taichi code below (``python3 fractal.py``) will give you an animation of
+Running the Taichi code below (``python3 fractal.py`` or ``ti example fractal``) will give you an animation of
 `Julia set <https://en.wikipedia.org/wiki/Julia_set>`_:
 
 .. image:: https://github.com/yuanming-hu/public_files/raw/master/graphics/taichi/fractal.gif

docs/index.rst

@@ -62,6 +62,7 @@ The Taichi Programming Language
    :maxdepth: 3
 
    gui
+   cli_utilities
    export_results
    global_settings
    faq

docs/matrix.rst

@@ -16,6 +16,7 @@ Matrices
 - ``U, sigma, V = ti.svd(A, ti.f32)`` (Note that ``sigma`` is a ``3x3`` diagonal matrix)
 - ``any(A)``
 - ``all(A)``
+- Currently, only ``+, -, @`` Matrix operations have experimental support in Python-scope. An exception will be raised if you try to apply other operations in Python-scope, use them in Taichi-scope (`@ti.kernel`) instead.
 
 TODO: doc here better like Vector. WIP
 

misc/minimal_timed.py

@@ -13,4 +13,4 @@ def p():
 p()
 
 print(f'{time.time() - t:.3f} s')
-ti.core.print_profile_info()
+ti.core.print_profile_info()