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Algorithm

AL-guh-rith-uhm
Foundational Concept

An algorithm is a finite, precisely specified sequence of steps for solving a problem or computing a result, the basic unit that every field of computing ultimately builds on. Informal algorithms are ancient, Euclid's method for finding the greatest common divisor of two numbers dates to around 300 BCE, but the formal mathematical concept of an algorithm, and of what problems can and cannot be solved by one, was only given a precise definition in 1936, when Alan Turing and, independently, Alonzo Church each proposed a formal model of computation, Turing's the Turing machine.

Facts
Disputed
Origin Year
1936
Informal algorithms are ancient practice, Euclid's algorithm dates to around 300 BCE; the formal mathematical definition of an algorithm as a precisely specified, mechanically followable procedure dates to 1936, when Turing and Church independently formalized computability.
Core Principle
A finite, precisely specified sequence of steps that solves a problem or computes a result. 1
FAQs

Where does the word algorithm come from?

It is a Latinization of the name of the Persian scholar al-Khwarizmi, who wrote on Indian arithmetic around 825 AD.

The word comes from the name of the Persian scholar al-Khwarizmi, who wrote on Indian arithmetic around 825 AD. When his texts were translated into Latin in the early 12th century, his name was Latinized as Algoritmi, and a translation titled Liber Algoritmi de numero Indorum began with the phrase Dixit Algoritmi, or "Thus spoke Al-Khwarizmi". In English the form algorism first meant calculating with place-value notation. Under the influence of the Greek word arithmos, meaning number, the Latin word became algorithmus, and by 1596 Thomas Hood used algorithm in English.
Connections

Associated With

Ada Lovelace, Pioneers

Lovelace's 1843 notes on the Analytical Engine included what is widely described as the first published algorithm intended for execution by a machine.

Source The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital RevolutionWalter Isaacson
Ada Lovelace, Pioneers

Why this is disputed. Ada Lovelace's 1843 notes on Babbage's Analytical Engine are widely described as containing the first published algorithm intended for execution by a machine (a method for computing Bernoulli numbers), and she is often called the first computer programmer for it. This attribution is genuinely disputed by historians: Babbage's own working notes contain earlier, unpublished program fragments of his own, and some scholars argue Lovelace's principal originality lay less in the algorithm itself than in her broader published insight that such a machine could manipulate symbols generally, not only numbers.

Source The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital RevolutionWalter Isaacson

In Field

Source Encyclopedia Britannica: Computer ScienceEncyclopedia Britannica Editors

Long-Form Articles

Sources
1. Encyclopedia Britannica: Computer Science
Encyclopedia Britannica Editors, Encyclopaedia Britannica Inc, 2024View the Source
Wikipedia: Algorithm
WikipediaLead section
Quote, Lead section
a finite sequence of mathematically rigorous logical instructions, typically used to solve a class of specific problems or to perform a computation.
View the Source
The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution
Walter Isaacson, Simon and Schuster, 2014Associated With: Ada Lovelace
Dissenting Readings (1 dissenting reading)
Associated With: Ada Lovelace

A minority but persistent strand of scholarship holds that Charles Babbage, not Ada Lovelace, deserves primary credit for the Bernoulli-number algorithm published in her 1843 notes. Babbage's own surviving working papers contain program fragments and calculating sequences for the Analytical Engine that predate the notes' publication, and correspondence between Lovelace and Babbage during the notes' preparation shows him supplying mathematical guidance and corrections. Proponents of this view do not dispute that Lovelace wrote and published the notes, including the algorithm and her own broader remarks on the machine's general symbol-manipulating potential, only that the algorithm's underlying mathematical work may have originated substantially with Babbage rather than being Lovelace's independent invention.

A dissenting reading, from Historians crediting Charles Babbage as primary author of the algorithmWalter Isaacson, The Innovators: How a Group of Hackers, Geniuses, and Geeks Created the Digital Revolution, Simon and Schuster, 2014
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