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From Daniel Lemire's Blog
#### What is “modern” programming?

As a young teenager, I dabbled with basic and some assembly. Things got serious when I learned Turbo Pascal. “Now we are talking”, I thought. Turbo Pascal offered...

From Daniel Lemire's Blog
#### Science and Technology links (July 14th, 2017)

PC shipments are at the lowest level of the last 10 years, and they have been declining for the last two years. Using smartphone data, researchers are able forContinue...

From Daniel Lemire's Blog
#### Pruning spaces faster on ARM processors with Vector Table Lookups

Last week, I asked how fast one could remove spaces from a string using ARM processors. On a particular benchmark, I got 2.4 cycles per byte using regular (scalar)...

From Daniel Lemire's Blog
#### Science and Technology links (July 7th, 2017)

People magazine recently named Julia Roberts, who is 49, as the World’s Most Beautiful Woman. Volvo plans to commercialize self-driving cars in 2020, and all electric...

From Daniel Lemire's Blog
#### Are your strings immutable?

A value is immutable if it cannot change. Immutability is a distinct notion than that of a constant. The speed of light in a vacuum is believed to be a universal...

From Daniel Lemire's Blog
#### Pruning spaces from strings quickly on ARM processors

Suppose that I give you a relatively long string and you want to remove all spaces from it. In ASCII, we can define spaces as the space character (‘ ‘), and the...

From Daniel Lemire's Blog
#### Science and Technology links (July 1st, 2017)

Canada is 150 years old today. The iPhone is 10 years old this year. We can safely say that the iPhone 7 is over a hundred times faster, in almost every way than...

From Daniel Lemire's Blog
#### Video game review… Nier: Automata

Single-player RPG games are having a tough time. Last year I reviewed Deus Ex: Mankind Divided. Though I felt it was an excellent game, it was not a commercialContinue...

From Daniel Lemire's Blog
#### Science and Technology links (June 23rd, 2017)

Elon Musk, Making Humans a Multi-Planetary Species, New Space. June 2017, 5(2): 46-61. Reportedly, Ikea is working on augmented reality software that would allow...

From Daniel Lemire's Blog
#### Top speed for top-k queries

Suppose that I give you a stream of values and you want to maintain the top-k smallest or largest values. You could accumulate all these values, sort them all and...

From Daniel Lemire's Blog
#### Science and Technology links (June 16th, 2017)

How much bandwidth do we have? It seems that each of our eyes has 1 megabyte per second. That’s about 100GB per day assuming you close one of your eyes and youContinue...

From Daniel Lemire's Blog
#### QuickSelect versus binary heap for top-k queries

In a previous post, I considered the problem of finding the k smallest (or k largest) elements from a stream of values. The naive approach is to collect all the...

From Daniel Lemire's Blog
#### Science and Technology links (June 9th, 2017)

This week, Apple told us about two new interesting pieces of technology. On the one hand, we have ARKit. It makes it easy for developers to build and deploy “augmented...

From Daniel Lemire's Blog
#### Quickly returning the top-k elements: computer science vs. the real world

A standard problem in computer science is to quickly return the smallest or largest K elements of a list. If the list is made of N elements, then we can solve this...

From Daniel Lemire's Blog
#### Science and Technology links (June 2nd, 2017)

Methylene blue rejuvenates old skin. You can buy methylene blue on Amazon and spray it on your face. It is reportedly safe, even in high concentration. Of course...

From Daniel Lemire's Blog
#### Unsigned vs. signed integer arithmetic

Given any non-negative integers x and d, we can write uniquely x = q d + r where q (the quotient) and r (the remainder) are non-negative and r is less than d. We...

From Daniel Lemire's Blog
#### Science and Technology links (May 26th, 2017)

Linux, the operating system driving cloud computing and the web, was developed using an open source model. For a time, Linux was seen as a direct competitor toContinue...

From Daniel Lemire's Blog
#### Counting exactly the number of distinct elements: sorted arrays vs. hash sets?

Suppose that you have ever larger sets of 64-bit integers, and you want to quickly find out how many distinct integers there are. So given {10, 12, 10, 16}, you...

From Daniel Lemire's Blog
#### Science and Technology links (May 18th, 2017)

Google has announced at its annual conference (I/O 2017) that it has computing pods capable of 11.5 petaflops. They are made of 64 customized TPU (processors specialized...

From Daniel Lemire's Blog
#### Educational backgrounds of the CEOs of the top 5 corporations in the US

Apple is the most valuable company in the US. The CEO is Tim Cook who has a bachelor of science in industrial engineering from Auburn University. The chairman is...