In Greek mythology

Greek mythology

Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...

 Procrustes (Προκρούστης) or "the stretcher [who hammers out the metal]", also known as Prokoptas or Damastes (Δαμαστής) "subduer", was a rogue smith and bandit from Attica who physically attacked people by stretching them or cutting off their legs, so as to force them to fit the size of an iron bed. In general, when something is Procrustean, different lengths or sizes or properties are fitted to an arbitrary standard.

In Greek mythology

In the Greek myth, Procrustes was a son of Poseidon

Poseidon

Poseidon was the god of the sea, and, as "Earth-Shaker," of the earthquakes in Greek mythology. The name of the sea-god Nethuns in Etruscan was adopted in Latin for Neptune in Roman mythology: both were sea gods analogous to Poseidon...

 with a stronghold on Mount Korydallos at Erineus, on the sacred way

Sacred Way

The Sacred Way , in ancient Greece, was the road from Athens to Eleusis. It was so called because it was the route taken by a procession celebrating the Eleusinian Mysteries...

 between Athens and Eleusis. There he had an iron bed, in which he invited every passer-by to spend the night, and where he set to work on them with his smith's hammer, to stretch them to fit. In later tellings, if the guest proved too tall, Procrustes would amputate the excess length; nobody ever fitted the bed exactly, because secretly Procrustes had two beds. Procrustes continued his reign of terror until he was captured by Theseus

Theseus

For other uses, see Theseus Theseus was the mythical founder-king of Athens, son of Aethra, and fathered by Aegeus and Poseidon, both of whom Aethra had slept with in one night. Theseus was a founder-hero, like Perseus, Cadmus, or Heracles, all of whom battled and overcame foes that were...

, travelling to Athens along the sacred way, who "fitted" Procrustes to his own bed:

He killed Damastes, surnamed Procrustes, by compelling him to make his own body fit his bed, as he had been wont to do with those of strangers. And he did this in imitation of Heracles

Heracles

Heracles ,born Alcaeus or Alcides , was a divine hero in Greek mythology, the son of Zeus and Alcmene, foster son of Amphitryon and great-grandson of Perseus...

. For that hero punished those who offered him violence in the manner in which they had plotted to serve him.

Killing Procrustes was Theseus's last adventure on his journey from Troezen

Troezen

Troezen is a small town and a former municipality in the northeastern Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality Troizinia, of which it is a municipal unit....

 to Athens

Athens

Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...

.

Contemporary usage

A Procrustean bed/couch is an arbitrary standard to which exact conformity is forced. In Edgar Allan Poe

Edgar Allan Poe

Edgar Allan Poe was an American author, poet, editor and literary critic, considered part of the American Romantic Movement. Best known for his tales of mystery and the macabre, Poe was one of the earliest American practitioners of the short story and is considered the inventor of the detective...

's The Purloined Letter

The Purloined Letter

"The Purloined Letter" is a short story by American author Edgar Allan Poe. It is the third of his three detective stories featuring the fictional C. Auguste Dupin, the other two being "The Murders in the Rue Morgue" and "The Mystery of Marie Rogêt". These stories are considered to be important...

, the private detective Dupin uses the metaphor of a Procrustean bed to describe the Parisian police's overly rigid method of looking for clues. Jacques Derrida

Jacques Derrida

Jacques Derrida was a French philosopher, born in French Algeria. He developed the critical theory known as deconstruction and his work has been labeled as post-structuralism and associated with postmodern philosophy...

, in "The Purveyor of Truth," his response to Jacques Lacan

Jacques Lacan

Jacques Marie Émile Lacan was a French psychoanalyst and psychiatrist who made prominent contributions to psychoanalysis and philosophy, and has been called "the most controversial psycho-analyst since Freud". Giving yearly seminars in Paris from 1953 to 1981, Lacan influenced France's...

's seminar on "The Purloined Letter" (1956), applies the metaphor to the structural analysis of texts: "By framing in this violent way, by cutting the narrated figure itself from a fourth side in order to see only triangles, one evades perhaps a certain complication." This is one of deconstruction

Deconstruction

Deconstruction is a term introduced by French philosopher Jacques Derrida in his 1967 book Of Grammatology. Although he carefully avoided defining the term directly, he sought to apply Martin Heidegger's concept of Destruktion or Abbau, to textual reading...

's central critiques of structural

Structuralism

Structuralism originated in the structural linguistics of Ferdinand de Saussure and the subsequent Prague and Moscow schools of linguistics. Just as structural linguistics was facing serious challenges from the likes of Noam Chomsky and thus fading in importance in linguistics, structuralism...

 (and formal

Formalism (literature)

Formalism is a school of literary criticism and literary theory having mainly to do with structural purposes of a particular text.In literary theory, formalism refers to critical approaches that analyze, interpret, or evaluate the inherent features of a text. These features include not only grammar...

) literary analysis.

Procrustes analysis

Procrustes analysis

In statistics, Procrustes analysis is a form of statistical shape analysis used to analyse the distribution of a set of shapes. The name Procrustes refers to a bandit from Greek mythology who made his victims fit his bed either by stretching their limbs or cutting them off.To compare the shape of...

is the process of performing a shape-preserving Euclidean transformation to a set of shapes. This removes variations in translation, rotation and scaling across the dataset in order to move them into a common frame of reference. This is generally the precursor to further statistical analysis. A related problem in linear algebra

Linear algebra

Linear algebra is a branch of mathematics that studies vector spaces, also called linear spaces, along with linear functions that input one vector and output another. Such functions are called linear maps and can be represented by matrices if a basis is given. Thus matrix theory is often...

 is the orthogonal Procrustes problem

Orthogonal Procrustes problem

The orthogonal Procrustes problem is a matrix approximation problem in linear algebra. In its classical form, one is given two matrices A and B and asked to find an orthogonal matrix R which most closely maps A to B...

of finding the closest orthogonal matrix

Orthogonal matrix

In linear algebra, an orthogonal matrix , is a square matrix with real entries whose columns and rows are orthogonal unit vectors ....

 to any given matrix

Matrix (mathematics)

In mathematics, a matrix is a rectangular array of numbers, symbols, or expressions. The individual items in a matrix are called its elements or entries. An example of a matrix with six elements isMatrices of the same size can be added or subtracted element by element...

.

A Procrustean solution is the undesirable practice of tailoring data to fit its container or some other preconceived structure. A common example from the business world is embodied in the notion that no résumé should exceed one page in length.

In a Procrustean solution in statistics, instead of finding the best fit line to a scatter plot of data, one first chooses the line one wants, then selects only the data that fits it, disregarding data that does not, so to "prove" some idea. It is a form of rhetorical deception made to forward one set of interests at the expense of others. The unique goal of the Procrustean solution is not win-win, but rather that Procrustes wins and the other loses. In this case, the defeat of the opponent justifies the deceptive means.

In computer science

Computer science

Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

, a Procrustean string is a fixed length string

String (computer science)

In formal languages, which are used in mathematical logic and theoretical computer science, a string is a finite sequence of symbols that are chosen from a set or alphabet....

 into which strings of varying lengths are placed. If the string inserted is too short, then it is padded out, usually with spaces or null character

Null character

The null character , abbreviated NUL, is a control character with the value zero.It is present in many character sets, including ISO/IEC 646 , the C0 control code, the Universal Character Set , and EBCDIC...

s. If the string inserted is too long, it is truncated

Truncation

In mathematics and computer science, truncation is the term for limiting the number of digits right of the decimal point, by discarding the least significant ones.For example, consider the real numbersThe result would be:- Truncation and floor function :...

. The concept is mentioned in the Sinclair ZX81

Sinclair ZX81

The ZX81 was a home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and was designed to be a low-cost introduction to home computing for the general public...

 and Sinclair Spectrum user manuals, where a portion of a string is replaced by another string using Procrustean assignment—the replacement string is truncated or padded in order to have length equal to the portion being replaced. Although the term did not catch on in wider usage, it appears in some references, notably FOLDOC.