Major refactor to pybind

.github/workflows/ci.yaml

@@ -22,7 +22,7 @@ jobs:
       run: |
         python3 -m venv .venv
         source .venv/bin/activate
-        python3 -m pip install nanobind
+        python3 -m pip install pybind11
         python3 -m pip install pytest
         python3 -m pip install --verbose .
 

CMakeLists.txt

@@ -1,6 +1,15 @@
-# Inspired and adapted from https://github.com/wjakob/nanobind_example/blob/master/CMakeLists.txt
-cmake_minimum_required(VERSION 3.16...3.26)
-project(drake_extension CXX)
+# Inspired and adapted from:
+# https://github.com/wjakob/nanobind_example/blob/master/CMakeLists.txt
+# and
+# https://github.com/pybind/scikit_build_example/blob/master/CMakeLists.txt
+cmake_minimum_required(VERSION 3.16...3.27)
+
+# 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)
 
 
 if (NOT SKBUILD)
@@ -33,41 +42,23 @@ find_package(drake CONFIG REQUIRED)
 
 # Try to import all Python components potentially needed by nanobind
 find_package(Python 3.12
-  REQUIRED COMPONENTS Interpreter Development.Module
-  OPTIONAL_COMPONENTS Development.SABIModule)
-
-# Import nanobind through CMake's find_package mechanism
-find_package(nanobind CONFIG REQUIRED)
+  REQUIRED COMPONENTS Interpreter Development.Module)
+find_package(pybind11 CONFIG REQUIRED)
 
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
-add_library(custom_system STATIC src/custom_system.cpp)
-target_link_libraries(custom_system PUBLIC drake::drake)
-set_target_properties(custom_system PROPERTIES CXX_VISIBILITY_PRESET default)
-
-nanobind_add_module(
-    # Name of the extension
-    drake_extension_ext
-    # Target the stable ABI for Python 3.12+, which reduces
-    # the number of binary wheels that must be built. This
-    # does nothing on older Python versions
-    STABLE_ABI
-    # Build libnanobind statically and merge it into the
-    # extension (which itself remains a shared library)
-    #
-    # If your project builds multiple extensions, you can
-    # replace this flag by NB_SHARED to conserve space by
-    # reusing a shared libnanobind across libraries
-    NB_STATIC
 
-    # Source code goes here
-    src/drake_extension_ext.cc)
-
-target_link_libraries(drake_extension_ext PUBLIC custom_system)
+# Add a library using FindPython's tooling (pybind11 also provides a helper like
+# this)
+python_add_library(drake_extension_ext MODULE src/drake_extension_ext.cpp WITH_SOABI)
+target_link_libraries(drake_extension_ext PUBLIC pybind11::headers drake::drake)
 set_target_properties(drake_extension_ext PROPERTIES CXX_VISIBILITY_PRESET default)
 
+# This is passing in the version as a define just as an example
+target_compile_definitions(_core PRIVATE VERSION_INFO=${PROJECT_VERSION})
+
 # Install directive for scikit-build-core
 install(TARGETS drake_extension_ext LIBRARY DESTINATION drake_extension)

pyproject.toml

@@ -1,11 +1,11 @@
 [build-system]
-requires = ["scikit-build-core >=0.4.3", "nanobind >=1.3.2"]
+requires = ["scikit-build-core>=0.3.3", "pybind11"]
 build-backend = "scikit_build_core.build"
 
 [project]
 name = "drake_extension"
 version = "0.0.1"
-description = "An example minimal project that compiles bindings using nanobind and scikit-build"
+description = "An example minimal project that compiles bindings using Pybind and scikit-build"
 readme = "README.md"
 requires-python = ">=3.12"
 authors = [
@@ -18,24 +18,71 @@ classifiers = [
 #  "drake",
 #]
 
+[project.optional-dependencies]
+test = ["pytest"]
+
 [project.urls]
 Homepage = "https://github.com/MAminSFV/drake_extension"
 
 
 [tool.scikit-build]
-# Protect the configuration against future changes in scikit-build-core
-minimum-version = "0.4"
+wheel.expand-macos-universal-tags = true
 
-# Setuptools-style build caching in a local directory
-build-dir = "build/{wheel_tag}"
 
-# Build stable ABI wheels for CPython 3.12+
-wheel.py-api = "cp312"
+[tool.pytest.ini_options]
+minversion = "6.0"
+addopts = ["-ra", "--showlocals", "--strict-markers", "--strict-config"]
+xfail_strict = true
+log_cli_level = "INFO"
+filterwarnings = [
+  "error",
+  "ignore::pytest.PytestCacheWarning",
+]
+testpaths = ["tests"]
 
-[tool.cibuildwheel]
-# Necessary to see build output from the actual compilation
-build-verbosity = 1
 
-# Run pytest to ensure that the package was correctly built
+[tool.cibuildwheel]
+build-frontend = "build[uv]"
 test-command = "pytest {project}/tests"
-test-requires = "pytest"
+test-extras = ["test"]
+
+[tool.cibuildwheel.pyodide]
+environment.CFLAGS = "-fexceptions"
+environment.LDFLAGS = "-fexceptions"
+build-frontend = {name = "build", args = ["--exports", "whole_archive"]}
+
+[tool.ruff]
+src = ["src"]
+
+[tool.ruff.lint]
+extend-select = [
+  "B",           # flake8-bugbear
+  "I",           # isort
+  "ARG",         # flake8-unused-arguments
+  "C4",          # flake8-comprehensions
+  "EM",          # flake8-errmsg
+  "ICN",         # flake8-import-conventions
+  "G",           # flake8-logging-format
+  "PGH",         # pygrep-hooks
+  "PIE",         # flake8-pie
+  "PL",          # pylint
+  "PT",          # flake8-pytest-style
+  "PTH",         # flake8-use-pathlib
+  "RET",         # flake8-return
+  "RUF",         # Ruff-specific
+  "SIM",         # flake8-simplify
+  "T20",         # flake8-print
+  "UP",          # pyupgrade
+  "YTT",         # flake8-2020
+  "EXE",         # flake8-executable
+  "NPY",         # NumPy specific rules
+  "PD",          # pandas-vet
+]
+ignore = [
+  "PLR09",    # Too many X
+  "PLR2004",  # Magic comparison
+]
+isort.required-imports = ["from __future__ import annotations"]
+
+[tool.ruff.lint.per-file-ignores]
+"tests/**" = ["T20"]

src/drake_extension/__init__.py

@@ -1,3 +1,3 @@
 __all__ = ["SimpleAdder"]
 
-from .custom_system import SimpleAdder
+from .drake_extension import SimpleAdder

src/drake_extension_ext.cpp

@@ -1,14 +1,51 @@
-#include <nanobind/nanobind.h>
+/**
+ * @file
+ * Provides an example of creating a simple Drake C++ system and binding it in
+ * pybind11, to be used with pydrake.
+ */
+#include <pybind11/pybind11.h>
 #include <drake/systems/framework/leaf_system.h>
 
-namespace nb = nanobind;
-using namespace nb::literals;
+namespace py = pybind11;
 
-NB_MODULE(drake_extension_ext, m) {
-  m.doc() = "Example module interfacing with Drake C++";
+using drake::systems::BasicVector;
+using drake::systems::Context;
+using drake::systems::LeafSystem;
+using drake::systems::kVectorValued;
+
+namespace drake_extension {
+
+/// Adds a constant to an input.
+template <typename T>
+class SimpleAdder : public LeafSystem<T> {
+ public:
+  explicit SimpleAdder(T add)
+      : add_(add) {
+    this->DeclareInputPort("in", kVectorValued, 1);
+    this->DeclareVectorOutputPort(
+        "out", BasicVector<T>(1), &SimpleAdder::CalcOutput);
+  }
+
+ private:
+  void CalcOutput(const Context<T>& context, BasicVector<T>* output) const {
+    auto u = this->get_input_port(0).Eval(context);
+    auto&& y = output->get_mutable_value();
+    y.array() = u.array() + add_;
+  }
+
+  const T add_{};
+};
+
+
+PYBIND11_MODULE(drake_extension, m) {
+  m.doc() = "Example module interfacing with pydrake and Drake C++";
+
+  py::module::import("pydrake.systems.framework");
 
   using T = double;
 
-  nb::class_<SimpleAdder<T>, LeafSystem<T>>(m, "SimpleAdder")
-      .def(nb::init<T>(), nb::arg("add"));
+  py::class_<SimpleAdder<T>, LeafSystem<T>>(m, "SimpleAdder")
+      .def(py::init<T>(), py::arg("add"));
 }
+
+}  // namespace drake_extension

tests/test_custom_system.py → tests/test_simple_adder.py

@@ -1,3 +1,4 @@
+import numpy as np
 from drake_extension import SimpleAdder
 
 from pydrake.systems.analysis import Simulator
@@ -24,4 +25,4 @@ def test_custom_system():
 
     x = logger.FindLog(simulator.get_context()).data()
     print("Output values: {}".format(x))
-    #assert np.allclose(x, 110.)
+    assert np.allclose(x, 110.)