Conformability: Difference between revisions

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→‎Frame conformability: NARS2000 has singleton extension for frame conformability
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== Frame conformability ==
== Frame conformability ==


The [[Rank operator]] and [[function rank]] check for conformability not on the entire [[shape]]s of arguments, but only on their [[frame]]s. The same procedure applies to determine whether two frames conform, and if <syntaxhighlight lang=apl inline>f</syntaxhighlight>'s result shape is known, then the result shape of <syntaxhighlight lang=apl inline>f⍤l r</syntaxhighlight> can be found by appending it to the shape obtained from conformability on the frames computed from [https://aplwiki.com/wiki/Rank_(operator) ranks] <syntaxhighlight lang=apl inline>l</syntaxhighlight> and <syntaxhighlight lang=apl inline>r</syntaxhighlight>. Rather than copying [[elements]] of the extended argument to match the other one, [[cell]]s are copied.
{{main|Frame agreement}}


No language uses [[singleton extension]] for frame conformability: [[SHARP APL]] and [[J]] do not implement singleton extension, and [[Dyalog APL]] and [[A+]] have singleton extension for scalar dyadics but not for Rank. Of these, [[J]] and [[A+]] use [[leading axis agreement]] while SHARP and Dyalog use only empty-frame extension, the equivalent of scalar extension.
The [[Rank operator]] and [[function rank]] check for conformability not on the entire [[shape]]s of arguments, but only on their [[frame]]s. The same procedure applies to determine whether two frames conform, and if function <syntaxhighlight lang=apl inline>f</syntaxhighlight>'s result shape is known, then the result shape of <syntaxhighlight lang=apl inline>f⍤l r</syntaxhighlight> can be found by appending it to the shape obtained from conformability on the frames computed from [[Rank (operator)|ranks]] <syntaxhighlight lang=apl inline>l</syntaxhighlight> and <syntaxhighlight lang=apl inline>r</syntaxhighlight>. Rather than copying [[element]]s of the extended argument to match the other one, [[cell]]s are copied.
 
Frame conformability may not allow [[singleton extension]] even when ordinary conformability supports it: [[Dyalog APL]], [[SHARP APL]], and [[A+]] have singleton extension for scalar dyadics but not for Rank (and [[J]] doesn't implement singleton extension). Of these, [[J]] and [[A+]] use [[leading axis agreement]] while SHARP and Dyalog use only empty-frame extension, the equivalent of scalar extension. However, [[NARS2000]] implements Rank with singleton extension for frames.


== External links ==
== External links ==

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