Numba

Numba

Original author(s)	Continuum Analytics
Developer(s)	Community project
Initial release	15 August 2012 (2012-08-15)
Stable release	0.39.0 / 6 July 2018 (2018-07-06)
Preview release	0.40.0dev0 / 10 July 2018 (2018-07-10)
Repository	https://github.com/numba/numba
Written in	Python, C
Operating system	Cross-platform
Type	Technical computing
Website	numba.pydata.org

Numba is an open-source NumPy-aware optimizing compiler for Python sponsored by Anaconda, Inc and a grant from the Gordon and Betty Moore Foundation. It uses the LLVM compiler infrastructure to compile Python to CPU and GPU machine code.^[1]

Traits

Numba compiles Python code with LLVM to code which can be natively executed by the CPU or GPU at runtime. This happens by decorating Python functions, which allows users to create native functions for different input types, or to create them on the fly:

@jit('f8(f8[:])')
def sum1d(my_double_array):
    total = 0.0
    for i in range(my_double_array.shape[0]):
        total += my_double_array[i]
    return total

This optimized function runs 200 times faster than the interpreted original function on a long NumPy array; and it is 30% faster than NumPy's builtin sum()function (version 0.27.0).^[2][3]

To make the above example work for any compatible input types automatically, we can create a function that specializes automatically:

@jit
def sum1d(my_array):
    ...

GPU Support

Numba can compile Python functions to GPU code. There are two approaches available currently:

• NVIDIA CUDA
• AMD HSA

@cuda.jit
def increment_a_2D_array(an_array):
    x, y = cuda.grid(2)
    if x < an_array.shape[0] and y < an_array.shape[1]:
       an_array[x, y] += 1

@hsa.jit(device=True)
def a_device_function(a, b):
    return a + b

Alternative approaches

The following projects are alternative approaches to accelerating Python:

• Cython
• PyPy
• Pythran

References