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Science and Technology links (August 9th 2020)
From Daniel Lemire's Blog

Science and Technology links (August 9th 2020)

The BBC reports that diversity and anti-bias training is of little use and may even be counterproductive if the goal is reduce biases: “The effect of bias training...

Performance tip: constructing many non-trivial objects is slow
From Daniel Lemire's Blog

Performance tip: constructing many non-trivial objects is slow

I started programming professionally when Java came out and right about when C++ was the “hot new thing”. Following the then-current fashion, I looked down at C...

Science and Technology links (August 1st 2020)
From Daniel Lemire's Blog

Science and Technology links (August 1st 2020)

In Japan, a large dam is being constructed almost entirely by robots. Naked mole rats are mammals that do not age in the sense that their fitness and mortalityContinue...

Science and Technology links (July 25th 2020)
From Daniel Lemire's Blog

Science and Technology links (July 25th 2020)

I was taught that human beings only arrived to America recently (15,000 years ago). It turns out that it is wrong. There were human beings in America 30,000 years...

Avoid character-by-character processing when performance matters
From Daniel Lemire's Blog

Avoid character-by-character processing when performance matters

When processing strings, it is tempting to view them as arrays of characters (or bytes) and to process them as such. Suppose that you would like to determine whether...

Downloading files faster by tweaking headers
From Daniel Lemire's Blog

Downloading files faster by tweaking headers

I was given a puzzle recently. Someone was parsing JSON files downloaded from the network from a bioinformatics URI. One JSON library was twice as fast at the other...

The cost of runtime dispatch
From Daniel Lemire's Blog

The cost of runtime dispatch

For high-performance software, it is sometimes needed to use different functions, depending on what the hardware supports. You might write different functions,Continue...

Science is the belief in the ignorance of experts
From Daniel Lemire's Blog

Science is the belief in the ignorance of experts

Science is the belief in the ignorance of experts said Richard Feynman. Feynman had a Nobel prize in physics. He was a remarquable educator: his lecture notes are...

Science and Technology links (July 11th 2020)
From Daniel Lemire's Blog

Science and Technology links (July 11th 2020)

Some upcoming Mercedes cars will have augmented reality head-up displays. Intel’s new standard for high-speed cables (thunderbolt) supports 3 GB/s bandwidth. (This...

GNU GCC does not round floating-point divisions to the nearest value
From Daniel Lemire's Blog

GNU GCC does not round floating-point divisions to the nearest value

I know that floating-point arithmetic is a bit crazy on modern computers. For example, floating-point numbers are not associative: 0.1+(0.2+0.3) == 0.599999999999999978...

Science and Technology links (June 20th 2020)
From Daniel Lemire's Blog

Science and Technology links (June 20th 2020)

UCLA researchers have achieved widespread rejuvenation in old mice through blood plasma diluation, a relatively simple process. (…) these results establish broad...

Computational overhead due to Docker under macOS
From Daniel Lemire's Blog

Computational overhead due to Docker under macOS

For my programming work, I tend to assume that I have a Linux environnement. That is true whether I am under Windows, under macOS or under a genuine Linux. HowContinue...

Reusing a thread in C++ for better performance
From Daniel Lemire's Blog

Reusing a thread in C++ for better performance

In a previous post, I measured the time necessary to start a thread, execute a small job and return. auto mythread = std::thread([] { counter++; }); mythread.join...

Science and Technology links (June 6th 2020)
From Daniel Lemire's Blog

Science and Technology links (June 6th 2020)

A small number of people are responsible for a disproportionate number of inventions and innovations. Why are these people different? Using neuroimaging techniques...

How Innovation Works (book review)
From Daniel Lemire's Blog

How Innovation Works (book review)

I read How Innovation Works by Matt Ridley in a few hours. It is a delicious book. Ridley distinguishes invention from innovation. The inventor creates something...

The Go compiler needs to be smarter
From Daniel Lemire's Blog

The Go compiler needs to be smarter

One of my favorite languages is the Go language. I love its simplicity. It is popular and useful in a cloud setting. Many popular tools are written in Go, and for...

Science and Technology links (May 30th 2020)
From Daniel Lemire's Blog

Science and Technology links (May 30th 2020)

We might soon be able to buy memory cards with speeds nearing 4 GB/s. For comparison, an expensive and recent macBook currently has a disk with a 2 GB/s bandwidth...

Mapping an interval of integers to the whole 64-bit range, fairly?
From Daniel Lemire's Blog

Mapping an interval of integers to the whole 64-bit range, fairly?

In my blog post A fast alternative to the modulo reduction, I described how one might map 64-bit values to an interval of integers (say from 0 to N) with minimal...

Programming inside in a container
From Daniel Lemire's Blog

Programming inside in a container

I have a small collection of servers, laptops and desktops. My servers were purchased and configured at different times. By design, they have different hardware...

Science and Technology links (May 16th 2020)
From Daniel Lemire's Blog

Science and Technology links (May 16th 2020)

Most of our processors, whether in our PCs or mobile phones, are 64-bit processors. In the case of your PC, it has been so for a couple of decades. Unfortunately...
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