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A LIMIT ERROR is an error message indicating that some imposed limit of the interpreter (one that is due to resource or design rather than theoretical limitations) has prevented an operation from completing. Common cases are that a program attempted to create an array whose rank exceeds the maximum rank or whose length along one axis would exceed the maximum allowed length. In Dyalog APL, the maximum rank is 15, so taking an Outer Product of two rank-8 arrays fails:

      ((81)2) ∘.+ ((81)3)
LIMIT ERROR: Rank of resultant array would exceed maximum permitted
Works in: Dyalog APL

In a 64-bit interpreter, it is rare to run into an array length limit, since the maximum allowed length is usually on the order of 2*64, and attempting to create an array this large may run into a DOMAIN ERROR or WS FULL, as most machines do not have enough addressable memory to store it. Empty arrays do not need storage space, so working with arrays with one length-0 axis and one long axis can sometimes reveal a LIMIT ERROR:

      ((0,2*63)2) , ((0,2*63)3)
Works in: Dyalog APL

LIMIT ERRORs may appear when working with components outside of APL such as files. Operating system limitations are usually reported as LIMIT ERRORs, since they are caused by constraints outside of the APL interpreter's control.

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