CMake integration

.github/workflows/python_publish.yml

@@ -0,0 +1,48 @@
+name: Build/publish Python Package
+
+on: push
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.x'
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install build twine
+      - name: Build package
+        run: |
+          python -m build --sdist --wheel
+      - name: Check package
+        run: |
+          python -m twine check dist/*
+      - name: Store the distribution packages
+        uses: actions/upload-artifact@v4
+        with:
+          name: python-package-distributions
+          path: dist/
+
+  publish-to-pypi:
+    if: startsWith(github.ref, 'refs/tags/')  # only publish to PyPI on tag pushes
+    needs:
+      - build
+    runs-on: ubuntu-latest
+    environment:
+      name: pypi
+    permissions:
+      id-token: write  # IMPORTANT: mandatory for trusted publishing
+    steps:
+      - name: Download distribution packages
+        uses: actions/download-artifact@v4
+        with:
+          name: python-package-distributions
+          path: dist/
+      - name: Publish to PyPI
+        uses: pypa/gh-action-pypi-publish@release/v1

.github/workflows/test.yml

@@ -0,0 +1,25 @@
+name: tests
+
+on: [push, pull_request]
+
+jobs:
+  pytest:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.12", "3.13"]
+
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install .[test]
+    - name: Test with pytest
+      run: |
+        pytest -vv tests

.gitignore

@@ -9,3 +9,12 @@ pyfeltor/dg/geo/__pycache__
 .eggs
 dist
 pyfeltor/_version.py
+
+uv.lock
+
+# ignore visual studio .vs table
+/.vs
+
+# CMake output
+build
+out

CMakeLists.txt

@@ -0,0 +1,75 @@
+## Inspired from https://github.com/pybind/scikit_build_example/blob/master/CMakeLists.txt
+
+# Require CMake 3.15+ (matching scikit-build-core) Use new versions of all
+# policies up to CMake 3.27
+cmake_minimum_required( VERSION "3.26")
+
+
+# Scikit-build-core sets these values for you, or you can just hard-code the
+# name and version.
+project(
+  ${SKBUILD_PROJECT_NAME}
+  VERSION ${SKBUILD_PROJECT_VERSION}
+  LANGUAGES CXX)
+
+include(cmake/CPM.cmake)
+set( CCCL_THRUST_DEVICE_SYSTEM "CPP")
+CPMAddPackage(
+    NAME feltor
+    GITHUB_REPOSITORY "feltor-dev/feltor"
+    VERSION 8.2
+    SYSTEM ON
+    EXCLUDE_FROM_ALL ON
+    OPTIONS "FELTOR_DG_WITH_MATRIX OFF" "FELTOR_FILE_WITH_NETCDF OFF"
+)
+
+
+# Find the module development requirements (requires FindPython from 3.17 or
+# scikit-build-core's built-in backport)
+# MW: https://cmake.org/cmake/help/latest/module/FindPython.html
+find_package(Python REQUIRED COMPONENTS Interpreter Development.Module)
+# Install pyprojects pybind11
+find_package(pybind11 CONFIG REQUIRED)
+
+# Needs to come after feltor because json is already included there
+# unless we use CPM_USE_LOCAL_PACKAGES
+CPMAddPackage( "gh:pybind/pybind11_json#0.2.15")
+
+
+# Follow the Makefile approach and compile each cpp into its own so lib
+
+set( PYFELTOR_LIBS
+    geometries
+    polynomial
+    solovev
+    guenter
+    circular
+    flux
+    mod
+    toroidal
+    utility
+)
+
+# Add a library using FindPython's tooling (pybind11 also provides a helper like
+# this)
+foreach( lib IN LISTS PYFELTOR_LIBS)
+    python_add_library(${lib} MODULE WITH_SOABI "pyfeltor/dg/geo/${lib}.cpp")
+    target_compile_features(${lib} PRIVATE cxx_std_17)
+    if (MSVC)
+        # warning level 4
+        target_compile_options(${lib} PRIVATE /W4 /permissive- /arch:AVX2 /O2 /EHsc -DFP_FAST_FMA -D_USE_MATH_DEFINES)
+    else()
+        # additional warnings
+        target_compile_options(${lib} PRIVATE -Wall -Wextra -Wpedantic -march=native -O2)
+    endif()
+
+    target_link_libraries(${lib} PRIVATE pybind11::headers)
+
+
+    target_link_libraries(${lib} PRIVATE feltor::dg::geometries)
+    target_link_libraries(${lib} PRIVATE pybind11_json)
+    # The install directory is the output (wheel) directory
+    install(TARGETS ${lib} DESTINATION pyfeltor/dg/geo)
+endforeach()
+
+

README.md

@@ -20,14 +20,13 @@ through python this enables many applications beyond simple simulations
 diagnostics. The only downside is of course that all functions are
 unparallelized in python.
 
-As a second addition, now also Feltor's geometries extension is available in python.
+As a second addition, Feltor's geometries extension is available in python.
 However, the geometries functions and classes are not re-implemented in python, but
-they are bound to python via the [pybind11](https://github.com/pybind11/pybind11)
+they are bound to python via the [pybind11](https://github.com/pybind/pybind11)
 library. As such the corresponding C++ binding code must be compiled in order
 to generate the module `dg.geo`.
 ## Installation
-### The pyfeltor.dg module
-> You need python3 to install this module
+> The `pyfeltor.dg.geo` part of the module contains python bindings for the underlying C++ [feltor](https://github.com/feltor-dev/feltor) code using [pybind11](https://github.com/pybind/pybind11). During installation the C++ code will be compiled using cmake, which may take a minute or two. 
 
 The simplest way is to install from the python package index [pypi](https://pypi.org/) via the package manager [pip](https://pip.pypa.io/en/stable/) v23.0
 ```bash
@@ -45,34 +44,6 @@ cd tests
 pytest-3 -s . # run all the unittests with output
 ```
 
-### The pyfeltor.dg.geo module
-Currently, the only way to install this module is via a local, editable install.
-Assuming that the pyfeltor.dg module was succesfully installed this way
-- the first step is to also install [feltor](https://github.com/feltor-dev/feltor)
-following the quick start guide for a base installation.
-- Second, instead of jsoncpp we here use the
-[nlohmann/json](https://github.com/nlohmann/json) parser available either as a
-system package `nlohmann-json3-dev`.
-- Next, we follow the first steps guide on [pybind11](https://github.com/pybind11/pybind11)
-and install it via `python3 -m pip install pybind11`.
-- Further, we install the 'python3-dev', `pybind11-dev` and `pybind11-json-dev` system packages for
-the corresponding C++ header files.
-
-Finally, invoke the Makefile in this repository
-```bash
-export FELTOR_PATH=path/to/feltor
-make -j 4
-```
-Replace `path/to/feltor` with the path to the Feltor library relative to the current
-directory. By default `FELTOR_PATH=../feltor`.
-
-That's it. With the editable install the `pyfeltor.dg.geo` module is now automatically
-imported together with `pyfeltor.dg`.
-You can test if it works by executing the test
-```bash
-cd tests
-pytest -s test_geometries
-```
 ## Usage
 
 Generally, pyfeltor is built to mimic the `dg` library in feltor.

cmake/CPM.cmake

@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: MIT
+#
+# SPDX-FileCopyrightText: Copyright (c) 2019-2023 Lars Melchior and contributors
+
+set(CPM_DOWNLOAD_VERSION 0.41.0)
+set(CPM_HASH_SUM "e570f03806b9aae2082ca5b950a9e6b3b41ad56972a78a876aedcaad16653116")
+
+if(CPM_SOURCE_CACHE)
+  set(CPM_DOWNLOAD_LOCATION "${CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+elseif(DEFINED ENV{CPM_SOURCE_CACHE})
+  set(CPM_DOWNLOAD_LOCATION "$ENV{CPM_SOURCE_CACHE}/cpm/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+else()
+  set(CPM_DOWNLOAD_LOCATION "${CMAKE_BINARY_DIR}/cmake/CPM_${CPM_DOWNLOAD_VERSION}.cmake")
+endif()
+
+# Expand relative path. This is important if the provided path contains a tilde (~)
+get_filename_component(CPM_DOWNLOAD_LOCATION ${CPM_DOWNLOAD_LOCATION} ABSOLUTE)
+
+file(DOWNLOAD
+     https://github.com/cpm-cmake/CPM.cmake/releases/download/v${CPM_DOWNLOAD_VERSION}/CPM.cmake
+     ${CPM_DOWNLOAD_LOCATION} EXPECTED_HASH SHA256=${CPM_HASH_SUM}
+)
+
+include(${CPM_DOWNLOAD_LOCATION})

pyfeltor/dg/__init__.py

@@ -1,11 +1,12 @@
 # docstring displayed by help(pyfeltor)
 """ The python version of the dg library
 """
-from . import create
-from .enums import bc, direction, inverse_bc, inverse_dir
-from .grid import Grid
-from .evaluation import evaluate, integrate
-try:
-    from . import geo
-except ImportError:
-    pass
+from . import create as create
+from . import geo as geo
+from .enums import bc as bc
+from .enums import direction as direction
+from .enums import inverse_bc as inverse_bc
+from .enums import inverse_dir as inverse_dir
+from .evaluation import evaluate as evaluate
+from .evaluation import integrate as integrate
+from .grid import Grid as Grid

pyfeltor/dg/create/__init__.py

@@ -1,7 +1,11 @@
 # docstring displayed by help(pyfeltor)
 """ The python version of the dg library, creation
 """
-from .weights import weights, abscissas, grid_from_abscissas
-from .derivative import dx, jump
-from .elliptic import elliptic
-from .interpolation import interpolation, projection
+from .derivative import dx as dx
+from .derivative import jump as jump
+from .elliptic import elliptic as elliptic
+from .interpolation import interpolation as interpolation
+from .interpolation import projection as projection
+from .weights import abscissas as abscissas
+from .weights import grid_from_abscissas as grid_from_abscissas
+from .weights import weights as weights

pyfeltor/dg/create/derivative.py

@@ -1,6 +1,7 @@
-from .dx import normed, jump_normed
 import scipy.sparse
 
+from .dx import jump_normed, normed
+
 
 def dx(dim, grid, bc, direction):
     deriv = normed(grid.n[dim], grid.N[dim], grid.h()[dim], bc, direction)