Difference between revisions of "Rank"

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== External Links ==
== External Links ==
[[wikipedia:Rank (computer programming)|Rank (computer programming)]]
* [[wikipedia:Rank (computer programming)|Rank (computer programming)]]
{{APL features}}[[Category:Array characteristics]]
{{APL features}}[[Category:Array characteristics]]

Latest revision as of 08:00, 9 July 2020

This page is about array rank, a number associated with every array. For numbers associated with a function specifying its argument rank, see function rank. For the operator that applies a function at a given rank, see Rank (operator).

In the APL array model, the rank of an array is the number of dimensions or axes in its structure, or the length of its shape. The traditional expression for the rank of an array A is ⍴⍴A. Because this expression results in a one-element vector rather than a scalar, it is idiomatic in languages with a Tally function to write ≢⍴A instead.

Arrays are given names based on their rank:

Rank Name
0 scalar
1 vector
2 matrix

Many APLs have a maximum rank. A function that would produce an array with rank greater than this maximum typically gives a LIMIT ERROR.

External Links

APL features [edit]
Built-ins Primitive functionPrimitive operatorQuad name
Array model ShapeRankDepthBoundIndex (Indexing) ∙ AxisRavelRavel orderElementScalarVectorMatrixSimple scalarSimple arrayNested arrayCellMajor cellSubarrayEmpty arrayPrototype
Data types Number (Boolean, Complex number) ∙ Character (String) ∙ BoxNamespace
Concepts and paradigms Leading axis theoryScalar extensionConformabilityScalar functionPervasionGlyphIdentity elementComplex floorTotal array ordering