feat: add free-threading example (#50)

Author: henryiii

.github/workflows/ci.yml

@@ -40,6 +40,21 @@ jobs:
     - uses: wntrblm/[email protected]
     - run: nox -s ${{ matrix.session }}
 
+  free-threading:
+    runs-on: ${{ matrix.runs-on }}
+    strategy:
+      fail-fast: false
+      matrix:
+        runs-on: [ubuntu-latest, windows-latest]
+    name: cibw on ${{ matrix.runs-on }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: pypa/[email protected]
+      with:
+          package-dir: projects/hello-free-threading
+      env:
+        CIBW_PRERELEASE_PYTHONS: True
+
   pass:
     if: always()
     needs: [checks]

.gitignore

@@ -56,6 +56,8 @@ docs/_build
 # build output (testing)
 skbuild/cmake_test_compile/*
 *.env
+wheelhouse
+dist/*
 
 # Generated manifests
 MANIFEST

noxfile.py

@@ -15,6 +15,8 @@
     "core-pybind11-hello",
     "hatchling-pybind11-hello",
 ]
+if sys.version_info >= (3, 13):
+    hello_list.append("hello-free-threading")
 
 
 @nox.session

projects/hello-free-threading/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.15...3.29)
+
+project(FreeComputePi LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 17 CACHE STRING "The C++ standard to use")
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+find_package(
+  Python
+  COMPONENTS Interpreter Development.Module
+  REQUIRED)
+
+python_add_library(_core MODULE src/freecomputepi/_core.cpp WITH_SOABI)
+
+install(TARGETS _core DESTINATION freecomputepi)

projects/hello-free-threading/pyproject.toml

@@ -0,0 +1,13 @@
+[build-system]
+requires = ["scikit-build-core >=0.9.5"]
+build-backend = "scikit_build_core.build"
+
+[project]
+name = "freecomputepi"
+version = "0.0.1"
+
+[tool.cibuildwheel]
+build = "cp313*"
+free-threaded-support = true
+test-command = "pytest {package} --durations=0"
+test-requires = ["pytest"]

projects/hello-free-threading/src/freecomputepi/__init__.py

@@ -0,0 +1,68 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+
+#include <random>
+
+
+static PyObject * pi(PyObject *self, PyObject *arg) {
+    int n = PyLong_AsLong(arg);
+    if (n == -1 && PyErr_Occurred()) {
+        return NULL;
+    }
+    double sum = 0.0;
+
+    std::random_device r;
+    std::default_random_engine e1(r());
+    std::uniform_real_distribution<double> uniform_dist(-1, 1);
+
+    for (int i = 0; i < n; i++) {
+        double x = uniform_dist(e1);
+        double y = uniform_dist(e1);
+        if (x * x + y * y <= 1.0) {
+            sum += 1.0;
+        }
+    }
+
+    return Py_BuildValue("d", 4.0 * sum / n);
+}
+
+extern "C" {
+
+static PyMethodDef core_methods[] = {
+    {"pi",  pi, METH_O, "Compute pi"},
+    {NULL, NULL, 0, NULL}        /* Sentinel */
+};
+
+static int _core_exec(PyObject *m) {
+    if (PyModule_AddFunctions(m, core_methods) < 0)
+        return -1;
+    return 0;
+}
+
+static PyModuleDef_Slot module_slots[] = {
+    {Py_mod_exec, (void*) _core_exec},
+    {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
+    #ifdef Py_GIL_DISABLED
+    {Py_mod_gil, Py_MOD_GIL_NOT_USED},
+    #endif
+    {0, NULL},
+};
+
+static struct PyModuleDef coremodule = {
+    PyModuleDef_HEAD_INIT,
+    "_core",
+    NULL,
+    0,
+    core_methods,
+    module_slots,
+    NULL,
+    NULL,
+    NULL,
+};
+
+
+PyMODINIT_FUNC PyInit__core(void) {
+    return PyModuleDef_Init(&coremodule);
+}
+
+};

projects/hello-free-threading/src/freecomputepi/_core.cpp

@@ -0,0 +1,30 @@
+import argparse
+import statistics
+import time
+from concurrent.futures import ThreadPoolExecutor
+
+from ._core import pi
+
+
+def pi_in_threads(threads: int, trials: int) -> float:
+    if threads == 0:
+        return pi(trials)
+    with ThreadPoolExecutor(max_workers=threads) as executor:
+        return statistics.mean(executor.map(pi, [trials // threads] * threads))
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--threads", type=int, default=0)
+    parser.add_argument("--trials", type=int, default=100_000_000)
+    args = parser.parse_args()
+
+    start = time.monotonic()
+    π = pi_in_threads(args.threads, args.trials)
+    stop = time.monotonic()
+
+    print(f"{args.trials} trials, {π = }, {stop - start:.4} s")
+
+
+if __name__ == "__main__":
+    main()

projects/hello-free-threading/src/freecomputepi/comp.py

@@ -0,0 +1,44 @@
+import argparse
+import random
+import statistics
+import time
+from concurrent.futures import ThreadPoolExecutor
+
+
+def pi(trials: int) -> float:
+    Ncirc = 0
+    ran = random.Random()
+
+    for _ in range(trials):
+        x = ran.uniform(-1, 1)
+        y = ran.uniform(-1, 1)
+
+        test = x * x + y * y
+        if test <= 1:
+            Ncirc += 1
+
+    return 4.0 * (Ncirc / trials)
+
+
+def pi_in_threads(threads: int, trials: int) -> float:
+    if threads == 0:
+        return pi(trials)
+    with ThreadPoolExecutor(max_workers=threads) as executor:
+        return statistics.mean(executor.map(pi, [trials // threads] * threads))
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--threads", type=int, default=0)
+    parser.add_argument("--trials", type=int, default=10_000_000)
+    args = parser.parse_args()
+
+    start = time.monotonic()
+    π = pi_in_threads(args.threads, args.trials)
+    stop = time.monotonic()
+
+    print(f"{args.trials} trials, {π = }, {stop - start:.4} s")
+
+
+if __name__ == "__main__":
+    main()

projects/hello-free-threading/src/freecomputepi/pure.py

@@ -0,0 +1,15 @@
+import freecomputepi.comp
+import freecomputepi.pure
+import pytest
+
+
+@pytest.mark.parametrize("threads", [0, 1, 2, 4])
+def test_pure(threads):
+    π = freecomputepi.pure.pi_in_threads(threads, 10_000_000)
+    assert π == pytest.approx(3.1415926535, rel=0.01)
+
+
+@pytest.mark.parametrize("threads", [0, 1, 2, 4])
+def test_comp(threads):
+    π = freecomputepi.comp.pi_in_threads(threads, 100_000_000)
+    assert π == pytest.approx(3.1415926535, rel=0.01)