Merge pull request #108 from lesteve/build-from-cython

[MRG] Build directly from cython sources

Author: fabianp

.gitignore

@@ -1,4 +1,5 @@
 *.pyc
+*.cpp
 *.so
 *~
 .#*

Makefile

@@ -5,24 +5,16 @@ DATADIR=$(HOME)/lightning_data
 
 # Compilation...
 
-CYTHONSRC= $(wildcard lightning/impl/*.pyx lightning/impl/randomkit/*.pyx)
-CSRC= $(CYTHONSRC:.pyx=.cpp)
-
 inplace:
 	$(PYTHON) setup.py build_ext -i
 
-all: cython inplace
-
-cython: $(CSRC)
+all: inplace
 
 clean:
-	rm -f lightning/impl/*.c lightning/impl/*.html
+	rm -f lightning/impl/*.cpp lightning/impl/*.html
 	rm -f `find lightning -name "*.pyc"`
 	rm -f `find lightning -name "*.so"`
 
-%.cpp: %.pyx
-	$(CYTHON) --cplus $<
-
 # Tests...
 #
 test-code: inplace

lightning/_build_utils.py

@@ -0,0 +1,59 @@
+"""
+Utilities useful during the build.
+"""
+# author: Loic Esteve
+# license: BSD
+import os
+
+from distutils.version import LooseVersion
+
+DEFAULT_ROOT = 'sklearn'
+CYTHON_MIN_VERSION = '0.23'
+
+try:
+    from sklearn._build_utils import maybe_cythonize_extensions
+except ImportError:
+    # maybe_cythonize_extensions exists from scikit-learn 0.18.1 onwards
+    def build_from_c_and_cpp_files(extensions):
+        """Modify the extensions to build from the .c and .cpp files.
+
+        This is useful for releases, this way cython is not required to
+        run python setup.py install.
+        """
+        for extension in extensions:
+            sources = []
+            for sfile in extension.sources:
+                path, ext = os.path.splitext(sfile)
+                if ext in ('.pyx', '.py'):
+                    if extension.language == 'c++':
+                        ext = '.cpp'
+                    else:
+                        ext = '.c'
+                    sfile = path + ext
+                sources.append(sfile)
+            extension.sources = sources
+
+
+    def maybe_cythonize_extensions(top_path, config):
+        """Tweaks for building extensions between release and development mode."""
+        is_release = os.path.exists(os.path.join(top_path, 'PKG-INFO'))
+
+        if is_release:
+            build_from_c_and_cpp_files(config.ext_modules)
+        else:
+            message = ('Please install cython with a version >= {0} in order '
+                       'to build a scikit-learn development version.').format(
+                           CYTHON_MIN_VERSION)
+            try:
+                import Cython
+                if LooseVersion(Cython.__version__) < CYTHON_MIN_VERSION:
+                    message += ' Your version of Cython was {0}.'.format(
+                        Cython.__version__)
+                    raise ValueError(message)
+                from Cython.Build import cythonize
+            except ImportError as exc:
+                exc.args += (message,)
+                raise
+
+            config.ext_modules = cythonize(config.ext_modules)
+