Add rebound recipe

Author: MMesch

recipes/recipes_emscripten/rebound/patches/0001-skip-c-extension-on-emscripten.patch

@@ -0,0 +1,29 @@
+--- a/setup.py	2026-07-02 13:26:02.036248410 +0200
++++ b/setup.py	2026-07-02 13:26:13.421075170 +0200
+@@ -42,12 +42,17 @@
+     extra_compile_args += ["-march=native", "-DAVX512"]
+ 
+ ##### C Extension
+-libreboundmodule = Extension(
+-    "librebound",
+-    sources=sorted(glob("src/*.c")),
+-    include_dirs=["src"],
+-    extra_link_args=extra_link_args,
+-    extra_compile_args=extra_compile_args,
+-)
+-
+-setup(ext_modules=[libreboundmodule])
++# On emscripten, librebound is built and installed separately as a
++# standalone shared library (see the librebound conda package).
++# Skip building the C extension here; only install the Python wrapper.
++if sys.platform == "emscripten":
++    setup()
++else:
++    libreboundmodule = Extension(
++        "librebound",
++        sources=sorted(glob("src/*.c")),
++        include_dirs=["src"],
++        extra_link_args=extra_link_args,
++        extra_compile_args=extra_compile_args,
++    )
++    setup(ext_modules=[libreboundmodule])

recipes/recipes_emscripten/rebound/patches/0002-load-librebound-from-prefix.patch

@@ -0,0 +1,31 @@
+--- a/rebound/__init__.py	2026-07-02 13:22:12.265323563 +0200
++++ b/rebound/__init__.py	2026-07-02 13:30:16.171832835 +0200
+@@ -29,13 +29,23 @@
+ except:
+     pass
+ 
+-# Import shared library
+-spec = importlib.util.find_spec("librebound")
+-if spec and spec.origin:
+-    __libpath__ = spec.origin
++# Import shared library.
++# On emscripten, librebound is installed as a standalone shared library
++# in the conda prefix (not as a Python extension module in site-packages).
++# Load it directly from there. Use a fixed ".so" suffix because the
++# library is built without Python ABI tags.
++if sys.platform == "emscripten":
++    import sysconfig as _sysconfig
++    _prefix = _sysconfig.get_path("data")
++    __libpath__ = os.path.join(_prefix, "lib", "librebound.so")
+     clibrebound = cdll.LoadLibrary(__libpath__)
+ else:
+-    raise ImportError("librebound not found")
++    spec = importlib.util.find_spec("librebound")
++    if spec and spec.origin:
++        __libpath__ = spec.origin
++        clibrebound = cdll.LoadLibrary(__libpath__)
++    else:
++        raise ImportError("librebound not found")
+ 
+ # Version
+ __version__ = c_char_p.in_dll(clibrebound, "reb_version_str").value.decode('ascii')

recipes/recipes_emscripten/rebound/patches/0003-fix-pyodide-import.patch

@@ -0,0 +1,18 @@
+--- a/rebound/horizons.py
++++ b/rebound/horizons.py
+@@ -11,12 +11,11 @@
+ 
+ HORIZONSBASEURL = "https://ssd.jpl.nasa.gov/api/horizons.api?"
+ 
+-if "pyodide" in sys.modules:
+-    from urllib.parse import urlencode
++try:
+     from pyodide.http import open_url as urlopen
+-    # Use CORS proxy
++    from urllib.parse import urlencode
+     HORIZONSBASEURL = "https://rebound.hanno-rein.de/api/horizons.api?"
+-else:
++except ImportError:
+     try:
+         from urllib.parse import urlencode
+         from urllib.request import urlopen

recipes/recipes_emscripten/rebound/recipe.yaml

@@ -0,0 +1,64 @@
+context:
+  name: rebound
+  version: 5.0.0
+
+package:
+  name: ${{ name }}
+  version: ${{ version }}
+
+source:
+- url: https://pypi.io/packages/source/${{ name[0] }}/${{ name }}/${{ name }}-${{ version }}.tar.gz
+  sha256: 9012bc4ceac42da8c1344f54e72b64da4720149875dc069d8e0dd1be0285dc04
+  patches:
+  - patches/0001-skip-c-extension-on-emscripten.patch
+  - patches/0002-load-librebound-from-prefix.patch
+  - patches/0003-fix-pyodide-import.patch
+
+build:
+  number: 0
+  script: ${PYTHON} -m pip install . ${PIP_ARGS} --no-deps --no-build-isolation
+
+  files:
+    exclude:
+    - '**/__pycache__/**'
+    - '**/*.pyc'
+    - '**/*.so'
+  python:
+    skip_pyc_compilation:
+    - '**/*.py'
+
+requirements:
+  build:
+  - cross-python_${{ target_platform }}
+  - python
+  - setuptools
+  - wheel
+  - pip
+  host:
+  - python
+  run:
+  - python
+  - librebound
+
+tests:
+- script: pytester
+  files:
+    recipe:
+    - test_import_rebound.py
+  requirements:
+    build:
+    - pytester
+    run:
+    - pytester-run
+    - librebound
+
+about:
+  homepage: https://github.com/hannorein/rebound
+  license: GPL-3.0-only
+  license_file: LICENSE
+  summary: An open-source multi-purpose N-body code
+  documentation: https://rebound.hanno-rein.de
+
+extra:
+  recipe-maintainers:
+  - mmesch

recipes/recipes_emscripten/rebound/test_import_rebound.py

@@ -0,0 +1,17 @@
+
+def test_import_rebound():
+    import rebound
+    assert rebound.__version__ == "5.0.0"
+
+
+def test_rebound_simulation():
+    import rebound
+
+    sim = rebound.Simulation()
+    sim.add(m=1.0)
+    sim.add(m=1.0e-3, a=1.0)
+    sim.integrate(100.0)
+
+    assert sim.N == 2
+    orbit = sim.particles[1].orbit(primary=sim.particles[0])
+    assert abs(orbit.a - 1.0) < 0.01