The C++ language is known for its slow build times. This problem is not present in the world of pure C, which might give a hint that the problem is caused by some C++ feature. In fact, it is caused by bad habit or writing code in headers, severely worsened by C++ templates and inspired by STL itself.
read moreBlog migrated to Pelican and GitHub pages
This article is a sort of report about blog migration.
On wordpress.com
Initially, I started this blog on wordpress.com. I chose wordpress.com thinking that I only need a small personal blog and I can easily live without any advanced features. I was pretty sure that I will post only technical articles, and do so quite rarely, so I searched for a free solution and wordpress.com was a good fit. And the experience was quite good in general: I did not have to configure anything, just choose a classic theme and go on writing.
A problem which I noticed rather quickly is that the width of the text in my blog was way too small. The amount of text fitting into one line was small, and it was especially ugly for source code fragments. When I wanted to post a piece of code from somewhere, I had to add split lines into pieces, so that the whole code fits and no scroll bar appears.
read moreVectorizing small fixed-size sort
After a long break, I can finally return to the topic which was started in the previous blog post.
Imagine that we have a small array of compile-time constant size with integers. For instance, N = 32. And we want to sort it as fast as possible. What is the best solution for this problem?
The wisest of you would suggest simply using std::sort, because every modern implementation of it is well-optimized and contains special handling of small subarrays to accelerate the generic quicksort algorithm. The ones who don't trust libraries would suggest using insertion sort: this is the algorithm usually used to handle small cases in std::sort. The performance geeks and regular stackoverflow visitors would definitely point to sorting networks: every question like "the fastest way to sort K integers" ends up with a solution based on them (N=6, N=10, what, why). I'm going to present a much less known way to sort small arrays of 32-bit keys, with performance comparable to sorting networks.
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