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 (May 22nd 2021)
Most computer chips today in flagship phones and computers use a process based on a 5 nm or larger resolution. Finer resolutions usually translate into lower energy...
From Daniel Lemire's Blog
Counting the number of matching characters in two ASCII strings
Suppose that you give me two ASCII strings having the same number of characters. I wish to compute efficiently the number of matching characters (same position,...
From Daniel Lemire's Blog
Converting binary integers to ASCII characters: Apple M1 vs AMD Zen2
Programmers often need to write integers as characters. Thus given the 32-bit value 1234, you might need a function that writes the characters 1234. We can useContinue...
From Daniel Lemire's Blog
Science and Technology links (May 15th 2021)
There were rainforests near the south pole 90 million years ago. Though commercial exchanges are typically win-win for both the buyer and the seller, people tend...
From Daniel Lemire's Blog
Constructing arrays of Boolean values in Java
It is not uncommon that we need to represent an array of Boolean (true or false) values. There are multiple ways to do it. The most natural way could be to construct...
From Daniel Lemire's Blog
The benefits of locality in random access
Modern computers have several layers of memory, from fast cache (sometimes called L1) all the way to main memory (RAM). A lot of performance-critical code relies...
From Daniel Lemire's Blog
Science and Technology links (May 1st 2021)
Growing your own food could lower your carbon footprint by 3-5%. In recent years, we have acquired the ability to measure biological age: your chronological age...
From Daniel Lemire's Blog
Ideal divisors: when a division compiles down to just a multiplication
The division instruction is one of the most expensive instruction in your CPU. Thus optimizing compilers often compile divisions by known constants down to a multiplication...
From Daniel Lemire's Blog
Some useful regular expressions for programmers
In my blog post, My programming setup, I stressed how important regular expressions are to my programming activities. Regular expressions can look intimidatingContinue...
From Daniel Lemire's Blog
A trichotomy of intellectual activity
I like to separate intellectual work among three categories: Emulation: the reproduction or direct application of existing ideas. Most academic work and maybe most...
From Daniel Lemire's Blog
Science and Technology links (April 17th 2021)
Moderna built their COVID 19 vaccine without having the virus on site. They viewed it as a software problem. Human and mice with red hair have elevated pain thresholds...
From Daniel Lemire's Blog
How fast can you sort arrays of integers in Java?
Programming languages come with sorting functions by default. We can often do much better. For example, Downs has showed that radix sort can greatly surpass default...
From Daniel Lemire's Blog
My programming setup
As my GitHub profile indicates, I program almost every single working day of the year. I program in C++, C, Go, Java, JavaScript, Python, R, Swift, Rust, C#; even...
From Daniel Lemire's Blog
Science and Technology links (March 27th 2021)
Scientists, including climate-science researchers, often travel to faraway places for conferences. Attending a live conference is time consuming and expensive.Continue...
From Daniel Lemire's Blog
Counting cycles and instructions on the Apple M1 processor
When benchmarking software, we often start by measuring the time elapsed. If you are benchmarking data bandwidth or latency, it is right measure. However, if you...
From Daniel Lemire's Blog
Apple’s M1 processor and the full 128-bit integer product
If I multiply two 64-bit integers (having values in [0, 264)), the product requires 128 bits. Intel and AMD processors (x64) can compute the full (128-bit) product...
From Daniel Lemire's Blog
Science and Technology links (March 6th 2021)
Increasing schooling does not improve social outcomes at a population level. Venitian glass was made near Venice as early as 450 BC. It spread worldwide through...
From Daniel Lemire's Blog
How does your programming language handle “minus zero” (-0.0)?
The ubiquitous IEEE floating-point standard defines two numbers to represent zero, the positive and the negative zeros. You also have the positive and negativeContinue...
From Daniel Lemire's Blog
Parsing Floating-point Numbers Really Fast in C#
Programmers often write out numbers as strings (e.g., 3.1416) and they want to read back the numbers from the string. If you read and write JSON or CSV files, you...
From Daniel Lemire's Blog