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Science and Technology links (April 29 2023)
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...

Hotspot performance engineering fails
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...

Vectorized trimming of line comments
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...

Science and Technology links (April 22 2023)
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...

Will emerging artificial intelligence boost research productivity?
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...

Defining interfaces in C++: concepts versus inheritance
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...

Science and Technology links (April 15 2023)
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...

Interfaces are not free in Go
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...

19 random digits is not enough to uniquely identify all human beings
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...

Consider using constexpr static function variables for performance in C++
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...

Science and Technology links (March 11 2023)
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...

Programming-language popularity by GitHub pull requests
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...

Are your memory-bound benchmarking timings normally distributed?
From Daniel Lemire's Blog

Are your memory-bound benchmarking timings normally distributed?

When optimizing software, we routinely measure the time that takes a given function or task. The typical assumption is that we get a normal distribution, and so...

What are we going to do about ChatGPT?
From Daniel Lemire's Blog

What are we going to do about ChatGPT?

Generative artificial intelligence, and in particular ChatGPT, has taken the world by storm. Some intellectuals are proposing we create a worldwide ban on advanced...

C++20: consteval and constexpr functions
From Daniel Lemire's Blog

C++20: consteval and constexpr functions

Optimizing compilers seek try to push as much of the computation as possible at compile time. In modern C++, you can declare a function as ‘constexpr’, meaningContinue...

Can GPT pass my programming courses?
From Daniel Lemire's Blog

Can GPT pass my programming courses?

Professeur Caplan reports that ChatGPT, the new AI that is all the rage, can pass his economics midterm and get an A. What about computer science ? I submittedContinue...

Counting cycles and instructions on ARM-based Apple systems
From Daniel Lemire's Blog

Counting cycles and instructions on ARM-based Apple systems

In my blog post Counting cycles and instructions on the Apple M1 processor, I showed how we could have access to “performance counters” to count how many cycles...

Runtime asserts are not free
From Daniel Lemire's Blog

Runtime asserts are not free

When writing software in C and C++, it is common to add C asserts to check that some conditions are satisfied at runtime. Often, it is a simple comparison between...

Science and Technology links (March 11 2023)
From Daniel Lemire's Blog

Science and Technology links (March 11 2023)

In 1500, China was the largest economy in the world, followed by India and France. The USA did not exist yet. In 1700, 4% of human beings lived in France. In the...

Trimming spaces from strings faster with SVE on an Amazon Graviton 3 processor
From Daniel Lemire's Blog

Trimming spaces from strings faster with SVE on an Amazon Graviton 3 processor

Programmers sometimes need to trim, or remove, characters, such as spaces from strings. It might be a surprising expensive task. In C, the following function is...
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