Add basic functionality for Cython functions and actors

.travis.yml

@@ -91,6 +91,7 @@ install:
   - ./.travis/install-dependencies.sh
   - export PATH="$HOME/miniconda/bin:$PATH"
   - ./.travis/install-ray.sh
+  - ./.travis/install-cython-examples.sh
 
   - cd python/ray/core
   - bash ../../../src/common/test/run_tests.sh
@@ -120,6 +121,7 @@ script:
   - python test/monitor_test.py
   - python test/trial_runner_test.py
   - python test/trial_scheduler_test.py
+  - python test/cython_test.py
 
   - python -m pytest python/ray/rllib/test/test_catalog.py
 

.travis/install-cython-examples.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+# Cause the script to exit if a single command fails
+set -e
+
+ROOT_DIR=$(cd "$(dirname "${BASH_SOURCE:-$0}")"; pwd)
+
+echo "PYTHON is $PYTHON"
+
+cython_examples="$ROOT_DIR/../examples/cython"
+
+if [[ "$PYTHON" == "2.7" ]]; then
+
+   pushd $cython_examples
+   pip install scipy
+   python setup.py install --user
+   popd
+
+elif [[ "$PYTHON" == "3.5" ]]; then
+   export PATH="$HOME/miniconda/bin:$PATH"
+
+   pushd $cython_examples
+   pip install scipy
+   python setup.py install --user
+   popd
+
+elif [[ "$LINT" == "1" ]]; then
+   export PATH="$HOME/miniconda/bin:$PATH"
+
+   pushd $cython_examples
+   pip install scipy
+   python setup.py install --user
+   popd
+
+else
+   echo "Unrecognized Python version."
+   exit 1
+fi

examples/cython/.gitignore

@@ -0,0 +1,6 @@
+build
+
+*.c
+*.so
+*.dylib
+*.dll

examples/cython/README.md

@@ -0,0 +1,28 @@
+# Cython in Ray
+
+To get started, run the following from directory ```$RAY_HOME/examples/cython```:
+bash
+```
+pip install scipy # For BLAS example
+python setup.py develop
+python cython_main.py --help
+```
+
+You can import the ```cython_examples``` module from a Python script or interpreter.
+
+## Notes
+- You **must** include the following two lines at the top of any ```*.pyx``` file:
+```python
+#!python
+# cython: embedsignature=True, binding=True
+```
+- You cannot decorate Cython functions within a ```*.pyx``` file (there are ways around this, but creates a leaky abstraction between Cython and Python that would be very challenging to support generally). Instead, prefer the following in your Python code:
+```
+some_cython_func = ray.remote(some_cython_module.some_cython_func)
+```
+- You cannot transfer memory buffers to a remote function (see ```example8```, which currently fails); your remote function must return a value
+- Have a look at ```cython_main.py```, ```cython_simple.pyx```, and ```setup.py``` for examples of how to call, define, and build Cython code, respectively. The Cython [documentation](http://cython.readthedocs.io/) is also very helpful.
+- Several limitations come from Cython's own [unsupported](https://github.com/cython/cython/wiki/Unsupported) Python features.
+
+## License
+We include some code examples from the [BrainIAK](https://github.com/brainiak/brainiak) package. There are licenses associated with those examples, which may (or may not!) cause issue. We can remove prior to any merge.

examples/cython/cython_examples/__init__.py

@@ -0,0 +1,29 @@
+from __future__ import absolute_import
+
+from .cython_simple import simple_func, fib, fib_int, \
+        fib_cpdef, fib_cdef, simple_class
+from .masked_log import masked_log
+
+from .cython_blas import \
+        compute_self_corr_for_voxel_sel, \
+        compute_kernel_matrix, \
+        compute_single_self_corr_syrk, \
+        compute_single_self_corr_gemm, \
+        compute_corr_vectors, \
+        compute_single_matrix_multiplication
+
+__all__ = [
+        'simple_func',
+        'fib',
+        'fib_int',
+        'fib_cpdef',
+        'fib_cdef',
+        'simple_class',
+        'masked_log',
+        'compute_self_corr_for_voxel_sel',
+        'compute_kernel_matrix',
+        'compute_single_self_corr_syrk',
+        'compute_single_self_corr_gemm',
+        'compute_corr_vectors',
+        'compute_single_matrix_multiplication'
+        ]