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Science and Technology links (September 18th 2021)
From Daniel Lemire's Blog

Science and Technology links (September 18th 2021)

4.5% of us are psychopaths. U.S. per capita CO2 emissions are lower than they were in 1918. 9/10 of People With Alzheimer’s Lose Some of Their Sense of Smell. Graphene...

Random identifiers are poorly compressible
From Daniel Lemire's Blog

Random identifiers are poorly compressible

It is common in data engineering to find that we have too much data. Thus engineers commonly seek compression routines. At the same time, random identifiers are...

How I debate
From Daniel Lemire's Blog

How I debate

Many of us feel that the current intellectual climate is difficult to bear. When I first noticed the phenomenon, people told me that it was because of Donald Trump...

The big-load anti-pattern
From Daniel Lemire's Blog

The big-load anti-pattern

When doing data engineering, it is common for engineers to want to first load all of the data in memory before processing the data. If you have sufficient memory...

How fast can you pipe a large file to a C++ program?
From Daniel Lemire's Blog

How fast can you pipe a large file to a C++ program?

Under many operating systems, you can send data from from one process to another using ‘pipes’. The term ‘pipe’ is probably used by analogy with plumbing and we...

Science and Technology links (July 31st 2021)
From Daniel Lemire's Blog

Science and Technology links (July 31st 2021)

Researchers built a microscope that might be 10 times better than the best available microscopes. Subsidizing college education can lower earnings due to lowerContinue...

Measuring memory usage: virtual versus real memory
From Daniel Lemire's Blog

Measuring memory usage: virtual versus real memory

Software developers are often concerned with the memory usage of their applications, and rightly so. Software that uses too much memory can fail, or be slow. Memory...

Faster sorted array unions by reducing branches
From Daniel Lemire's Blog

Faster sorted array unions by reducing branches

When designing an index, a database or a search engine, you frequently need to compute the union of two sorted sets. When I am not using fancy low-level instructions...

Science and Technology links (July 10th 2021)
From Daniel Lemire's Blog

Science and Technology links (July 10th 2021)

We use CRISPR, a state-of-the-art gene editing technique, to edit the genes of live human patients in a clinical trials. A clinical trial has begun concerning an...

Compressing JSON: gzip vs zstd
From Daniel Lemire's Blog

Compressing JSON: gzip vs zstd

JSON is the de facto standard for exchanging data on the Internet. It is relatively simple text format inspired by JavaScript. I say “relatively simple” because...

Science and Technology links (June 26th 2021)
From Daniel Lemire's Blog

Science and Technology links (June 26th 2021)

Reportedly, half of us own a smartphone. It is often reported that women or visible minority earn less money. However, ugly people are doing comparatively evenContinue...

How long should you work on a problem ?
From Daniel Lemire's Blog

How long should you work on a problem ?

Lev Reyzin says that working too long on a problem might be unproductive: I, personally, have diminishing (or negative?) returns to my creative work as I explicitly...

Science and Technology links (June 12th 2021)
From Daniel Lemire's Blog

Science and Technology links (June 12th 2021)

We completed the sequencing of the human genome. AstraZeneca’s drug Lynparza cut combined risk of recurrence of breast cancer or death by 42% among women in study...

Computing the number of digits of an integer even faster
From Daniel Lemire's Blog

Computing the number of digits of an integer even faster

I my previous blog post, I documented how one might proceed to compute the number of digits of an integer quickly. E.g., given the integer 999, you want 3 but given...

Computing the number of digits of an integer quickly
From Daniel Lemire's Blog

Computing the number of digits of an integer quickly

Suppose I give you an integer. How many decimal digits would you need to write it out? The number ‘100’ takes 3 digits whereas the number ’99’ requires only two...

All Models are Wrong
From Daniel Lemire's Blog

All Models are Wrong

All models are wrong, but some are useful is a common saying in statistics. It does not merely apply to statistics, however. It is general observation. Box (1976)...

Science and Technology links (May 22nd 2021)
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...

Counting the number of matching characters in two ASCII strings
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,...

Converting binary integers to ASCII characters: Apple M1 vs AMD Zen2
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...

Science and Technology links (May 15th 2021)
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...
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