LIMIT ERROR: Difference between revisions

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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:
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:
<source lang=apl>
<syntaxhighlight lang=apl>
       ((8⍴1)⍴2) ∘.+ ((8⍴1)⍴3)
       ((8⍴1)⍴2) ∘.+ ((8⍴1)⍴3)
LIMIT ERROR: Rank of resultant array would exceed maximum permitted
LIMIT ERROR: Rank of resultant array would exceed maximum permitted
       ((8⍴1)⍴2)∘.+((8⍴1)⍴3)
       ((8⍴1)⍴2)∘.+((8⍴1)⍴3)
                 ∧
                 ∧
</source>
</syntaxhighlight>
{{Works in|[[Dyalog APL]]}}
{{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 <source lang=apl inline>2*64</source>, 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:
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 <syntaxhighlight lang=apl inline>2*64</syntaxhighlight>, 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:
<source lang=apl>
<syntaxhighlight lang=apl>
       ((0,2*63)⍴2) , ((0,2*63)⍴3)
       ((0,2*63)⍴2) , ((0,2*63)⍴3)
LIMIT ERROR
LIMIT ERROR
       ((0,2*63)⍴2),((0,2*63)⍴3)
       ((0,2*63)⍴2),((0,2*63)⍴3)
                   ∧
                   ∧
</source>
</syntaxhighlight>
{{Works in|[[Dyalog APL]]}}
{{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.
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}}
{{APL features}}[[Category:Errors]]

Latest revision as of 22:13, 10 September 2022

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:

      ((8⍴1)⍴2) ∘.+ ((8⍴1)⍴3)
LIMIT ERROR: Rank of resultant array would exceed maximum permitted
      ((8⍴1)⍴2)∘.+((8⍴1)⍴3)
                ∧
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)
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 Primitives (functions, operators) ∙ Quad name
Array model ShapeRankDepthBoundIndex (Indexing) ∙ AxisRavelRavel orderElementScalarVectorMatrixSimple scalarSimple arrayNested arrayCellMajor cellSubarrayEmpty arrayPrototype
Data types Number (Boolean, Complex number) ∙ Character (String) ∙ BoxNamespaceFunction array
Concepts and paradigms Conformability (Scalar extension, Leading axis agreement) ∙ Scalar function (Pervasion) ∙ Identity elementComplex floorArray ordering (Total) ∙ Tacit programming (Function composition, Close composition) ∙ GlyphLeading axis theoryMajor cell search
Errors LIMIT ERRORRANK ERRORSYNTAX ERRORDOMAIN ERRORLENGTH ERRORINDEX ERRORVALUE ERROREVOLUTION ERROR