Procrustes

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In Greek mythology, Procrustes (the stretcher), also known as Damastes (subduer) and Polypemon (harming much), was a bandit from Attica. He had his stronghold in the hills outside Eleusis. There, he had an iron bed into which he invited every passerby to lie down. If the guest proved too tall, he would amputate the excess length; if the victim was found too short, he was then stretched out on the rack until he fit. Nobody would ever fit in the bed because it was secretly adjustable: Procrustes would stretch or shrink it upon sizing his victims from afar. Procrustes continued his reign of terror until he was captured by Theseus, who "fitted" Procrustes to his own bed and cut off his head and feet (since Theseus was a stout fellow, the bed had been set on the short position). Killing Procrustes was the last adventure of Theseus on his journey from Troezen to Athens.

[edit] Derived meanings

A Procrustean bed is an arbitrary standard to which exact conformity is forced. Sometimes the term is applied to the pan and scan process of cropping motion pictures for television and home video.

Procrustes analysis is the name for 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.

In computer science, a Procrustean string is a fixed length string 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 characters. If the string inserted is too long, it is truncated. This term was made somewhat popular by its use and explanation in the Sinclair ZX81 user manual. Although the term did not catch on in wider usage, it appears in some references, notably FOLDOC.