What’s faster in Numba @jit functions, NumPy or the math package?

Update 2016-01-16: Numba 0.23 released and tested - results added at the end of this post A while back I was using Numba to accelerate some image processing I was doing and noticed that there was a difference in speed whether I used functions from NumPy or their equivalent from the standard Python math package … Continue reading What’s faster in Numba @jit functions, NumPy or the math package?

Numba nopython mode in versions 0.11 and 0.13 of Numba

My previous posts regarding the Numba package for Python used version 0.11.  Recently, Numba has gone through some major changes in version 0.12.1, 0.12.2 and 0.13.  My last post explained how I had used the nopython keyword argument to speed up my code.  Importantly, it showed that removing array allocation steps (i.e. np.zeros(...)) allowed Numba … Continue reading Numba nopython mode in versions 0.11 and 0.13 of Numba

Learning Python: Numba nopython context for extra speed

The Numba and Python logos

Update 2014/12/23: I should have pointed out long ago that this post has been superseded by my post "Numba nopython mode in versions 0.11 and 0.13 of Numba". Lets say you are trying to accelerate a Python function whose inner loop calls a Numpy function, in my case that function was exp.  Using the @autojit … Continue reading Learning Python: Numba nopython context for extra speed

Corrections to “Learning Python: Eight ways to filter an image” – fixing my Numba speed problems

My post comparing different ways to implement the bilateral filter, "Learning Python: Eight ways to filter and image", showed several versions attempting to use Numba.  However, Numba failed to produce the amazing speed ups others have reported.  The fault is my own.  Here is the new version 2 of my Numba code: The first, and … Continue reading Corrections to “Learning Python: Eight ways to filter an image” – fixing my Numba speed problems

Learning Python: Eight ways to filter an image

Today's post is going to look at fast ways to filter an image in Python, with an eye towards speed and memory efficiency.  My previous post put Numba to use, accelerating my code for generating the Burning Ship fractal by about 10x.  This got me thinking about other places where I could use Numba.  That, … Continue reading Learning Python: Eight ways to filter an image

Learning Python: Parallel processing with the Parallel Python module, with some Numba added in

Introduction: Parallel Python and the Burning Ship fractal I have previously used Matlab for a lot of my prototyping work and its parfor Parallel For loop construct has been a relatively easy way to get code to use all the cores available in my desktop.  Now that I am teaching myself Python, I decided to … Continue reading Learning Python: Parallel processing with the Parallel Python module, with some Numba added in

Making PyOpenCL handle NumPy arrays as images

The OpenCL logo.

PyOpenCL Image objects take a shape tuple that gives (width, height, depth), but NumPy arrays specify shape in the order (rows, columns, ...) a.k.a. (height, width, ...) where the ellipsis indicates higher dimensions.  What's important is that the width and height dimensions have been swapped.  The PyOpenCL documentation suggests creating the NumPy arrays in the … Continue reading Making PyOpenCL handle NumPy arrays as images

My computer can’t add (part 2)

In My computer can't add (part 1) introduced Kahan summation and showed how it helps to improve the accuracy of summing up a large number of floating point values.  Kahan's algorithm is fine for this task, but what happens when one tries combining the result of two sums?  What if you need to multiply the compensated … Continue reading My computer can’t add (part 2)

My computer can’t add (part 1)

The first few digits of Pi, rendered with each digit having a smaller height than the preceding one.

I recently asked some of my colleagues a question relating to the Kahan compensated summation algorithm and was greeted with blank stares and the question "What's that?"  This caught me off guard as I had known about it for a few years.  I can't remember how I found out about it, but I think that … Continue reading My computer can’t add (part 1)