Compiling a PIXIE library from Cython

This notebook is building upon knowledge of Compiling a PIXIE library from C

This notebook requires a working clang 14 compiler and cython. You can install them with conda install clang=14 cython.

Building on the previous C library, the simplest way to make Python binding for add_f64 is to use Cython. Here, we make cy_add() for use in Python code:

%%writefile simple_add_cython.pyx
cimport cython

cdef public void add_f64(double *x, double *y, double *out):
    out[0] = x[0] + y[0]

def cy_add(x, y):
    cdef cython.double out = 0.0
    cdef cython.double a = x
    cdef cython.double b = y
    add_f64(&a, &b, &out)
    return out

Next, use PIXIE to compile the Cython source file into a PIXIE library:

from pixie import PIXIECompiler, TranslationUnit, ExportConfiguration
from pixie.targets import get_default_configuration

src = "simple_add_cython.pyx"
tus = [
    TranslationUnit.from_cython_source(src),
]

export_config = ExportConfiguration()
export_config.add_symbol(python_name='add_f64',
                         symbol_name='add_f64',
                         signature='void(double*, double*, double*)',)
compiler = PIXIECompiler(library_name='simple_add_cython', # name must match cython file
                         translation_units=tus,
                         export_configuration=export_config,
                         **get_default_configuration(),
                         python_cext=True,
                         output_dir='.')
compiler.compile()

Now that we have made a DSO with name simple_add_cython as a Python C-extension library, we can import it.

import simple_add_cython

The library is Cython module as expected with an export of cy_add:

help(simple_add_cython)

Output:

Help on module simple_add_cython:

NAME
    simple_add_cython

FUNCTIONS
    cy_add(x, y)

DATA
    __PIXIE__ = {'available_isas': ['v8_6a', 'v8_4a', 'baseline'], 'bitcod...
    __test__ = {}

FILE
    /path/to/simple_add_cython.cpython-311-darwin.so

simple_add_cython.cy_add(1, 2)

Output:

3.0

It is also a PIXIE library, so it has the __PIXIE__ attribute on the module:

pixie_dict = simple_add_cython.__PIXIE__

pixie_dict

Output:

{'symbols': {'add_f64': {'void(double*, double*, double*)': {'ctypes_cfunctype': ctypes.CFUNCTYPE.<locals>.CFunctionType,
    'symbol': 'add_f64',
    'module': None,
    'source_file': None,
    'address': 4569974972,
    'cfunc': <CFunctionType object at 0x1110690d0>,
    'metadata': None}}},
 'c_header': ['<write it>'],
 'linkage': None,
 'bitcode': b'...[skipped]...',
 'uuid': '82506a0f-8d17-4e2a-a2db-e6760f507910',
 'is_specialized': False,
 'available_isas': ['v8_6a', 'v8_4a', 'baseline'],
 'specialize': <function specialize.<locals>.impl(baseline_cpu='host', baseline_features=None, targets_features=None)>,
 'selected_isa': 'v8_4a'}

All the exported PIXIE symbols are accessible as shown previously in the C example.

pixie_dict['symbols']

Output:

{'add_f64': {'void(double*, double*, double*)': {'ctypes_cfunctype': ctypes.CFUNCTYPE.<locals>.CFunctionType,
   'symbol': 'add_f64',
   'module': None,
   'source_file': None,
   'address': 4397500604,
   'cfunc': <CFunctionType object at 0x105fc8950>,
   'metadata': None}}}