Communications of the ACM
Refine your search:
How the “Frontier” Became the Slogan of Uncontrolled AI
Artificial intelligence (AI) has been billed as the next frontier of humanity: the newly available expanse whose exploration …
From Daniel Lemire's Blog
Science and Technology links (January 26th, 2018)
We have reached “peak coal” meaning that coal usage is going to diminish in the coming years. McGill professor Ishiang Shih has been accused by the US government...
From Daniel Lemire's Blog
Initializing arrays quickly in Swift: be wary of Sadun’s initializers
Swift is Apple’s go-to programming language. It is the new default to build applications for iPhones. It also runs well on Linux. It is not as low-level as C or...
From Daniel Lemire's Blog
Microbenchmarking is hard: virtual machine edition
To better understand software performance, we often use small controlled experiments called microbenchmarks. In an earlier post, I remarked that it is hard to reason...
From Daniel Lemire's Blog
Science and Technology links (January 19th, 2018)
The Raspberry Pi 3, a $15-dollar computer that I use for various fun projects, is 15 times more powerful than the Cray-1 supercomputer, but it is 130,000 timesContinue...
From Daniel Lemire's Blog
Ridiculously fast base64 encoding and decoding
Computers store data as streams of bits. Binary files like image, audio or video files are allowed to contain just about any sequence of bits. However, we alsoContinue...
From Daniel Lemire's Blog
Microbenchmarking calls for idealized conditions
Programmers use software benchmarking to measure the speed of software. We need to distinguish system benchmarking, where one seeks to measure the performance of...
From Daniel Lemire's Blog
Science and Technology links (January 12th, 2018)
A few years ago, researchers in Danemark expressed concerns regarding high concentrations of pesticides that are showing up in urine samples of Danish mothers and...
From Daniel Lemire's Blog
How fast can you bit-interleave 32-bit integers? (SIMD edition)
In a previous post, I asked how fast one could interleave the bits between two 32-bit integers. That is, given 0b1011 (11 in decimal) and 0b1100 (12 in decimal)...
From Daniel Lemire's Blog
How fast can you bit-interleave 32-bit integers?
A practical trick in software is to “bit-interleave” your data. Suppose that I have two 4-bit integers like 0b1011 (11 in decimal) and 0b1100 (12 in decimal). I...
From Daniel Lemire's Blog
Science and Technology links (January 5th, 2018)
You still have to burn more energy creating solar panels than solar panels can give back in a useful lifetime. Tyler Cowen writes: There is now a doctrine of what...
From Daniel Lemire's Blog
Can 32-byte alignment alleviate 4K aliasing?
In my previous post, I considered some performance problems that can plague simple loops that read and write data… for (int i = 0; i < a.length; ++i) { a[i] +=Continue...
From Daniel Lemire's Blog
Don’t make it appear like you are reading your own recent writes
Richard Statin recently published a Java benchmark where the performance of a loop varies drastically depending on the size of the arrays involved. The loop isContinue...
From Daniel Lemire's Blog
Year 2017: technological highlights
DeepStack and Libratus become the first computer programs to beat professinal poker players. We are using synthetic cartilage to help people with arthritis. Stem...
From Daniel Lemire's Blog
Multicore versus SIMD instructions: the “fasta” case study
Setting aside graphics processors, most commodity processors support at least two distinct parallel execution models. Most programmers are familiar with the multicore...
From Daniel Lemire's Blog
Science and Technology links (December 29th, 2017)
It is often believed that, in the developed world, more land is used for human beings (cities, agriculture) as time goes by. That is not true: Forests are spreading...
From Daniel Lemire's Blog
Personal reflections on 2017
Year 2017 is coming to an end. As a kid, I would have surely imagined that by 2017, I would be living in space. But then I can chat with Amazon’s servers through...
From Daniel Lemire's Blog
Science and Technology links (December 22nd, 2017)
Bitcoins are electronic records that are meant to be used as currency. They have become increasingly popular and expensive. Reportedly, the famous investment bank...
From Daniel Lemire's Blog
Science and Technology links (December 15th, 2017)
Scientists found a human gene which, when inserted into mice, makes their brain grow larger. David Brin has a series of classical sci-fi books where we “uplift”...
From Daniel Lemire's Blog
If all your attributes are independent two-by-two… are all your attributes independent?
Suppose that you are working on a business problem where you have multiple attributes… maybe you have a table with multiple columns such as “age, gender, income...
From Daniel Lemire's Blog