Communications of the ACM
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Chinese Hacking of U.S. Critical Infrastructure
Everyone is writing about an interagency and international report on Chinese hacking of US critical infrastructure.
Lots of…
From Daniel Lemire's Blog
Expected performance of a Bloom filter
A hash function is a function that maps a value (such as a string) to an integer value. Typically, we want random-looking values. A Bloom filter is a standard data...
From Daniel Lemire's Blog
The absurd cost of finalizers in Go
The Go programming language makes it easy to call C code. Suppose you have the following C functions: char* allocate() { return (char*)malloc(100); } void free_allocated...
From Daniel Lemire's Blog
Computing the UTF-8 size of a Latin 1 string quickly (ARM NEON edition)
While most of our software relies on Unicode strings, we often still encounter legacy encodings such as Latin 1. Before we convert Latin 1 strings to Unicode (e...
From Daniel Lemire's Blog
ARM instructions do “less work”?
Modern processors can execute several instructions per cycle. Because processors cannot easily run faster (in terms of clock speed), vendors try to get their processors...
From Daniel Lemire's Blog
Science and Technology links (May 6 2023)
Artificial intelligence (ChatGPT) can provide better answers to patients than physicians. Eating chocolate might affect your brain and cognitive functions. It may...
From Daniel Lemire's Blog
Graviton 3, Apple M2 and Qualcomm 8cx 3rd gen: a URL parsing benchmark
Whenever you enter a URL into a system, it must be parsed and validated. It is a surprisingly challenging task: it may require hundreds of nanoseconds and possibly...
From Daniel Lemire's Blog
Under Linux, libSegFault and addr2line are underrated
Many modern programming languages like Java produce useful error messages when they fail. Some indicate where in the program (e.g., down to the line of source code)...
From Daniel Lemire's Blog
Science and Technology links (April 29 2023)
Ovaries age quickly in women. By the age of 40, most ovaries are poorly functional. However, there is an ongoing clinical trial to check whether the drug rapamycin...
From Daniel Lemire's Blog
Hotspot performance engineering fails
Developers often believe that software performance follows a Pareto distribution: 80% of the running time is spent in 20% of the code. Using this model, you can...
From Daniel Lemire's Blog
Vectorized trimming of line comments
A French graduate student reached out by email yesterday with the following problem. Consider a format such as TOML which has line comments: when a ‘#’ character...
From Daniel Lemire's Blog
Science and Technology links (April 22 2023)
There are many theories regarding what biological aging. Animals can differ by up to six orders of magnitude (100000x) in longevity. Some animal species like the...
From Daniel Lemire's Blog
Will emerging artificial intelligence boost research productivity?
Bryan Caplan, an economist, raised an interesting question on Twitter: why aren’t people celebrating the fact that tools like GPT might soon allow us to produce...
From Daniel Lemire's Blog
Defining interfaces in C++: concepts versus inheritance
In a previous blog post, I showed how you could define ‘an interface’ in C++ using concepts. For example, I can specify that a type should have the methods has_next...
From Daniel Lemire's Blog
Science and Technology links (April 15 2023)
Some university professor include ‘trigger warnings’ in their course material, to warn students that potentially disturbing content may be encountered. According...
From Daniel Lemire's Blog
Interfaces are not free in Go
We are all familiar with the concept even if we are not aware of it: when you learn about arithmetic in school, you use the same mathematical symbols whether you...
From Daniel Lemire's Blog
19 random digits is not enough to uniquely identify all human beings
Suppose that you assigned everyone an 19 digit number. What is the probability that two human beings would have the same number? It is an instance of the Birthday...
From Daniel Lemire's Blog
Consider using constexpr static function variables for performance in C++
When programming, we often need constant variables that are used within a single function. For example, you may want to look up characters from a table. The following...
From Daniel Lemire's Blog
Science and Technology links (March 11 2023)
Robert Metcalfe won the Turing Award (the ‘Computer Science Nobel Prize’) for his work on early networking. According to DBLP, Metcalfe published 11 journal articles...
From Daniel Lemire's Blog
Programming-language popularity by GitHub pull requests
GitHub is probably the most popular software repository in the world. One important feature on GitHub is the ‘pull request’: we often contribute to a piece of software...
From Daniel Lemire's Blog