2,954
edits
Indices: Difference between revisions
Jump to navigation
Jump to search
→History: Other dialects supporting Indices inverse
m (Text replacement - "<source" to "<syntaxhighlight") |
(→History: Other dialects supporting Indices inverse) |
||
| Line 72: | Line 72: | ||
Indices (<syntaxhighlight lang=apl inline>⍸</syntaxhighlight>) was first introduced to APL, and the [[nested array model]], by [[NARS2000]]. Originally defined only for vectors, the generalised definition <syntaxhighlight lang=apl inline>(,R)/,⍳⍴1/R</syntaxhighlight> was introduced in about 2013 after some experimentation with alternatives.<ref>NARS2000 Wiki. [http://wiki.nars2000.org/index.php?title=Indices&direction=next&oldid=863 Indices]. Old revision: 2013-05-26.</ref> Where (<syntaxhighlight lang=apl inline>⍸</syntaxhighlight>) was added to [[Dyalog APL 16.0]] (June 2017), with the nearly-identical definition <syntaxhighlight lang=apl inline>{(,⍵)⌿,⍳⍴⍵}</syntaxhighlight>, but also with the restriction that the argument be Boolean. This restriction that was lifted to allow non-negative integers in [[Dyalog APL 18.0|18.0]] (2020). For a [[scalar]] <syntaxhighlight lang=apl inline>I</syntaxhighlight>, Dyalog's definition gives <syntaxhighlight lang=apl inline>I⍴⊂⍬</syntaxhighlight> for <syntaxhighlight lang=apl inline>⍸I</syntaxhighlight>, while NARS2000 returned <syntaxhighlight lang=apl inline>I⍴1</syntaxhighlight>. By January 2018, NARS2000 switched to Dyalog's definition, removing the discrepancy for scalar arguments. | Indices (<syntaxhighlight lang=apl inline>⍸</syntaxhighlight>) was first introduced to APL, and the [[nested array model]], by [[NARS2000]]. Originally defined only for vectors, the generalised definition <syntaxhighlight lang=apl inline>(,R)/,⍳⍴1/R</syntaxhighlight> was introduced in about 2013 after some experimentation with alternatives.<ref>NARS2000 Wiki. [http://wiki.nars2000.org/index.php?title=Indices&direction=next&oldid=863 Indices]. Old revision: 2013-05-26.</ref> Where (<syntaxhighlight lang=apl inline>⍸</syntaxhighlight>) was added to [[Dyalog APL 16.0]] (June 2017), with the nearly-identical definition <syntaxhighlight lang=apl inline>{(,⍵)⌿,⍳⍴⍵}</syntaxhighlight>, but also with the restriction that the argument be Boolean. This restriction that was lifted to allow non-negative integers in [[Dyalog APL 18.0|18.0]] (2020). For a [[scalar]] <syntaxhighlight lang=apl inline>I</syntaxhighlight>, Dyalog's definition gives <syntaxhighlight lang=apl inline>I⍴⊂⍬</syntaxhighlight> for <syntaxhighlight lang=apl inline>⍸I</syntaxhighlight>, while NARS2000 returned <syntaxhighlight lang=apl inline>I⍴1</syntaxhighlight>. By January 2018, NARS2000 switched to Dyalog's definition, removing the discrepancy for scalar arguments. | ||
The [[#inverse|inverse]] of Indices | The [[#inverse|inverse]] of Indices was defined by [[Extended Dyalog APL]] in 2018, and supported in [[dzaima/APL]] when it added Indices a few months later. Support has been added in [[Dyalog APL 18.0]], and later [[April]] (for boolean vector results only) and [[KAP]]. The inverse <code>/⁼</code> is defined in [[BQN]], with the extension that the argument is implicitly sorted.<ref>BQN documentation. [https://mlochbaum.github.io/BQN/doc/replicate.html#inverse Indices and Replicate § Inverse].</ref> | ||
== External links == | == External links == | ||