Concept

Run count — where it appears

How many maximal runs of one symbol a Burrows-Wheeler transform has. It falls as a text repeats itself and is one of the two measures a compressed index can be proportional to; what it counts is repeated contexts rather than repeated characters.

Named by 4 essays across 2 fields — each of them below, with the objects they name alongside it.

twelve essays — runs0.491generated, matched0.109twelve essays — phrases0.213generated, matched0.046eight source modules — runs0.461generated, matched0.122eight source modules — phrases0.210generated, matched0.050ten revisions of one file — runs0.126generated, matched0.113ten revisions of one file — phrases0.067generated, matched0.047per character24,576 characters a partdivergence 0.02

A corpus that was not generated

Every collection in five strands has been copies of a generated text with a fraction of its characters replaced — three numbers, one dial. Here is one that was not — twelve essays, eight source modules, ten revisions of one file — measured beside the model of it.

text · Document
① prose144,617 chars12 docs · median 12,335① code106,283 chars8 docs · median 13,150① revisions75,658 chars10 docs · median 7,774② essays1,004,822 chars82 docs · median 12,335② captions549,210 chars2,214 docs · median 230② history174,282 chars14 docs · median 12,963① the first freeze · ② the second6 parts

A million characters of the same thing

Every measurement this collection has published about real text was taken on twenty-four thousand characters, because the phrase count was quadratic. It is linear now, so here is the same corpus at forty times the size — and what forty times does to its own numbers.

text · Document
10⁴10⁵10⁶characters in the collectionshuffled ÷ real, phraseswhat the order is wortha million characters of prose · phrases per characterx1.37 over the sweep

The half of a fall that is the logarithm

Phrases per character on a real collection of essays fall by a factor of 2.34 as it grows. A shuffle of the same characters falls by 1.70. Nearly three quarters of the movement is arithmetic, and no definition of the measure says so.

wrong · Document
1.0%10.0%0.11fraction of characters changedper characterthe real runsthe real phrasesgenerated runsgenerated phrasesten revisions of one file · 24,580 characters2.32% against 3.24%

The dial that has no setting

The generator has one parameter. The real version history's run count asks it for 2.3% and its phrase count asks for 3.2% — and the reason is not that the dial is badly calibrated. Real edits average 7.3 characters a block and generated ones average 1.04.

wrong · Document

Named alongside it

The objects these essays reach for when they reach for this one.

ControlCorpusPhrase countRepetitionAlphabetEntropyDocument collectionGenerated collectionIndex sizeLogarithmMeasurementScale

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