Communications of the ACM
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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
Performance tip: avoid unnecessary copies
Copying data in software is cheap, but it is not at all free. As you start optimizing your code, you might find that copies become a performance bottleneck. Let...
From Daniel Lemire's Blog
Validating gigabytes of Unicode strings per second… in C#?
We have been working on a fast library to validate and transcode Unicode and other formats such as base64 in C++: simdutf. We wondered: could we achieve the same...
From Daniel Lemire's Blog
Rolling your own fast matrix multiplication: loop order and vectorization
If you must multiply matrices, you should use dedicated libraries. However, we sometimes need to roll our own code. In C++, you can quickly write your own Matrix...
From Daniel Lemire's Blog
Scan HTML faster with SIMD instructions: Chrome edition
Modern processors have instructions to process several bytes at once. Effectively all processors have the capability of processing 16 bytes one once. These instructions...
From Daniel Lemire's Blog
Quickly checking whether a string needs escaping
In software, we often represent strings by surrounding them with quotes ("). What happens if the string itself contains quotes? We then need to escape the string...
From Daniel Lemire's Blog
Never reason from the results of a sampling profiler
In the quest for software optimization, a trusty companion is the sampling profiler, a tool available in most programming languages. These profilers work unobtrusively...
From Daniel Lemire's Blog
Science and Technology links (May 25 2024)
Artificial intelligence is far more efficient at producing content than human beings, as far as carbon emissions go. Human brains got larger by over 5% betweenContinue...
From Daniel Lemire's Blog
Learning from the object-oriented mania
Back when I started programming professionally, every expert and every software engineering professor would swear by object-oriented programming. Resistance was...
From Daniel Lemire's Blog
Forwarding references in C++
In C++, there are different ways to pass a value to a function. Typically, at any given time, an object in C++ ‘belongs’ to a single function. The various waysContinue...
From Daniel Lemire's Blog
Peer review is not the gold standard in science
Peer review as we know it today was introduced very late, over a century after the scientific revolution. It happened after Einstein’s time… arguably the most productive...
From Daniel Lemire's Blog
How fast can construct small list of strings in C for Python?
Python is probably the most popular programming language in the world right now. Python is easy to extend using C code. You may want to return from Python a small...
From Daniel Lemire's Blog
Should Node.js be built with ClangCL under Windows?
Under Windows, when using Visual Studio to build C++ code, there are two possible compiler strategies. The Visual Studio compiler (often referred to as MSVC) is...
From Daniel Lemire's Blog
Careful with Pair-of-Registers instructions on Apple Silicon
Egor Bogatov is an engineer working on C# compiler technology at Microsoft. He had an intriguing remark about a performance regression on Apple hardware following...
From Daniel Lemire's Blog
Large language models (e.g., ChatGPT) as research assistants
Software can beat human beings at most games… from Chess to Go, and even poker. Large language models like GPT-4 offered through services such as ChatGPT allowContinue...
From Daniel Lemire's Blog
How do you recognize an expert?
Go back to the roots: experience. An expert is someone who has repeatedly solved the concrete problem you are encountering. If your toilet leaks, an experienced...
From Daniel Lemire's Blog
How quickly can you break a long string into lines?
Suppose that you receive a long string and you need to break it down into lines. Consider the simplified problems where you need to break the string into segments...
From Daniel Lemire's Blog
Science and Technology links (April 13 2024)
Our computer hardware exchange data using a standard called PCI Express. Your disk, your network and your GPU are limited by what PCI Express can do. Currently,...
From Daniel Lemire's Blog
Greatest common divisor, the extended Euclidean algorithm, and speed!
We sometimes need to find the greatest common divisor between two integers in software. The fastest way to compute the greatest common divisor might be the binary...
From Daniel Lemire's Blog
A simple algorithm to compute the square root of an integer, byte by byte
A reader asked me for some help in computing (1 – sqrt(0.5)) to an arbitrary precision, from scratch. A simpler but equivalent problem is to compute the squareContinue...
From Daniel Lemire's Blog