Reinstate setup.py to build Cython modules

setup.py

@@ -0,0 +1,66 @@
+import os
+import platform
+import numpy
+# Always prefer setuptools over distutils
+from setuptools import setup
+from setuptools import Extension
+
+WINDOWS = platform.system().lower() == "windows"
+
+# check whether user has Cython
+try:
+    import Cython
+except ImportError:
+    have_cython = False
+else:
+    have_cython = True
+
+# set extension
+libraries = [] if WINDOWS else ["m"]
+if have_cython:  # convert the pyx file to a .c file if cython is available
+    from Cython.Build import cythonize
+    print('Running cython')
+    ext_modules = [Extension("cpnest.parameter",
+                             sources=[os.path.join("cpnest", "parameter.pyx")],
+                             include_dirs=['cpnest', numpy.get_include()],
+                             libraries=libraries,
+                             extra_compile_args=["-O3","-ffast-math"])]
+    ext_modules = cythonize(ext_modules)
+else:
+    # just compile the included parameter.c (already converted from
+    # parameter.pyx) file
+    ext_modules = [Extension("cpnest.parameter",
+                             sources=[os.path.join("cpnest", "parameter.c")],
+                             include_dirs=['cpnest', numpy.get_include()],
+                             libraries=libraries,
+                             extra_compile_args=["-O3","-ffast-math"])]
+
+here = os.path.abspath(os.path.dirname(__file__))
+
+# Get the long description from the relevant file
+with open(os.path.join(here, 'DESCRIPTION.rst'), encoding='utf-8') as f:
+        long_description = f.read()
+
+
+setup(
+        name='cpnest',
+        use_scm_version=True,
+        description='CPNest: Parallel nested sampling',
+        classifiers=[
+            'Development Status :: 4 - Beta',
+            'License :: OSI Approved :: MIT License',
+            'Programming Language :: Python :: 3',
+            'Programming Language :: Python :: 3.12',
+            'Programming Language :: Python :: 3.11',
+            'Programming Language :: Python :: 3.10',
+            'Programming Language :: Python :: 3.9'
+            ],
+        packages=['cpnest'],
+        include_dirs = [numpy.get_include()],
+        setup_requires=['numpy', 'cython', 'setuptools_scm'],
+        package_data={"": ['*.c', '*.pyx', '*.pxd']},
+        entry_points={},
+        test_suite='tests',
+        ext_modules=ext_modules
+        )
+