#16: bindings: Update README to describe python binding build

README.md

@@ -16,4 +16,43 @@ using Paraview. Additionally, the task visualizer can produce PNGs
 directly using a VTK workflow to render a visualization of ranks and
 tasks over phases.
 
-![Example Output PNG](./docs/example-output-image.png)
+![Example Output PNG](./docs/example-output-image.png)
+
+## Building the Python bindings
+
+###Requirements
+
+In order to build the python bindings, make sure you have a Python <ins>`3.8` or `3.9`</ins> environment, with the `nanobind` package installed. You can install `nanobind` with `pip`:
+
+```bash
+pip install nanobind
+```
+
+You must have a C++ compiler that supports C++17, and `cmake` >= 3.17.
+
+Finally, you must have a (<ins>C++</ins>) [VTK](https://vtk.org/) build available on your system. We recommend building from source, and the currently tested version is `9.3.0`. You can find instructions for building VTK [here](https://gitlab.kitware.com/vtk/vtk/-/blob/master/Documentation/docs/build_instructions/build.md).
+
+### Building
+
+To build the python bindings, you must specify in the `VTTV_VTK_DIR` environment variable the path to the VTK build directory:
+
+```bash
+export VTTV_VTK_DIR=/path/to/vtk/build
+```
+
+
+Then, to install python-environment-wide the binded `vt-tv` python module, run:
+
+```bash
+pip install .
+```
+**Optional**
+
+To specify the number of parallel jobs to use during the build, you can set the `VTTV_J` environment variable:
+
+```bash
+export VTTV_J=8
+```
+
+> [!NOTE]
+> Behind the scenes, the usual `cmake` and `make` commands are run. Depending on your system, this can cause the install process to be lengthy as it will be compiling the entire `vt-tv` library.

setup.py

@@ -29,11 +29,11 @@ def build_extension(self, ext):
     build_temp = os.path.join('python-build', 'build', 'temp')
     os.makedirs(build_temp, exist_ok=True)
 
-    vtk_dir = os.environ.get('VTK_DIR')
+    vtk_dir = os.environ.get('VTTV_VTK_DIR')
     if not vtk_dir:
-      raise RuntimeError("Environment variable VTK_DIR is required")
+      raise RuntimeError("Environment variable VTTV_VTK_DIR is required")
 
-    jobs = os.environ.get('JOBS', os.cpu_count())
+    jobs = os.environ.get('VTTV_JOBS', os.cpu_count())
 
     cmake_args = ['-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=' + extdir,
                   '-DPYTHON_EXECUTABLE=' + sys.executable,