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Dyalog APL versions: Difference between revisions
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Support was added for 128-bit [[decimal floating point]] numbers (from [[wikipedia:IEEE 754|IEEE 754]]-2008), using the [[wikipedia:densely packed decimal|densely packed decimal]] (DPD) format internally. The [[system variable]] <source lang=apl inline>⎕FR</source> (Floating point Representation) was added, with the options 645 for 64-bit binary (5) floats and 1287 for 128-bit decimal (7) floats. Because of the increased precision of decfs, an additional system variable <source lang=apl inline>⎕DCT</source> was added to control [[comparison tolerance]] with decfs enabled, with the default value <source lang=apl inline>1E¯28</source>. When <source lang=apl inline>⎕FR</source> is 645, <source lang=apl inline>⎕CT</source> controls the comparison tolerance, but when it is 1287, <source lang=apl inline>⎕DCT</source> controls comparison tolerance. Support for interfacing with [[.NET]] decimal floats was also added. Because no complex decimal float type was added, version 13.1 broke Dyalog APL's strict numeric type hierarchy, introducing potential [[Array model#Numeric type coercion|changes in precision]] when placing values together in an array. | Support was added for 128-bit [[decimal floating point]] numbers (from [[wikipedia:IEEE 754|IEEE 754]]-2008), using the [[wikipedia:densely packed decimal|densely packed decimal]] (DPD) format internally. The [[system variable]] <source lang=apl inline>⎕FR</source> (Floating point Representation) was added, with the options 645 for 64-bit binary (5) floats and 1287 for 128-bit decimal (7) floats. Because of the increased precision of decfs, an additional system variable <source lang=apl inline>⎕DCT</source> was added to control [[comparison tolerance]] with decfs enabled, with the default value <source lang=apl inline>1E¯28</source>. When <source lang=apl inline>⎕FR</source> is 645, <source lang=apl inline>⎕CT</source> controls the comparison tolerance, but when it is 1287, <source lang=apl inline>⎕DCT</source> controls comparison tolerance. Support for interfacing with [[.NET]] decimal floats was also added. Because no complex decimal float type was added, version 13.1 broke Dyalog APL's strict numeric type hierarchy, introducing potential [[Array model#Numeric type coercion|changes in precision]] when placing values together in an array. | ||
Identity functions <source lang=apl inline>⊣</source> ([[Same]], [[Left]]) and <source lang=apl inline>⊢</source> ([[Same]], [[Right]]) were introduced. Monadic <source lang=apl inline>+</source>, formerly called [[Identity]], was changed to [[Conjugate]] (a change which did not break backwards compatibility, because prior to the introduction of [[complex number]]s the two functions were indistinguishable). Dyadic functions [[Take]] (<source lang=apl inline>↑</source>), [[Drop]] (<source lang=apl inline>↓</source>), and [[ | Identity functions <source lang=apl inline>⊣</source> ([[Same]], [[Left]]) and <source lang=apl inline>⊢</source> ([[Same]], [[Right]]) were introduced. Monadic <source lang=apl inline>+</source>, formerly called [[Identity]], was changed to [[Conjugate]] (a change which did not break backwards compatibility, because prior to the introduction of [[complex number]]s the two functions were indistinguishable). Dyadic functions [[Take]] (<source lang=apl inline>↑</source>), [[Drop]] (<source lang=apl inline>↓</source>), and [[Squad Indexing|Index]] (<source lang=apl inline>⌷</source>) were extended to allow short left arguments, matching [[SHARP APL]]'s interpretation of the [[leading axis theory]]. | ||
A [[primitive operator]] (<source lang=apl inline>⍠</source>) was introduced as an alternative spelling of the existing [[system operator]] [[Variant]] (<source lang=apl inline>⎕OPT</source>), with a functionality similar to one sketched by [[Ken Iverson]] (<source lang=apl inline>:</source>)<ref>[[Ken Iverson|Kenneth E. Iverson]], [https://www.jsoftware.com/papers/APLDictionary.htm A Dictionary of APL], VI. Conjunctions, [https://www.jsoftware.com/papers/APLDictionary1.htm#colon Custom]. APL Quote Quad, Volume 18, Number 1, 1987-09.</ref> and implemented in [[J]] (<source lang=j inline>!.</source>). | A [[primitive operator]] (<source lang=apl inline>⍠</source>) was introduced as an alternative spelling of the existing [[system operator]] [[Variant]] (<source lang=apl inline>⎕OPT</source>), with a functionality similar to one sketched by [[Ken Iverson]] (<source lang=apl inline>:</source>)<ref>[[Ken Iverson|Kenneth E. Iverson]], [https://www.jsoftware.com/papers/APLDictionary.htm A Dictionary of APL], VI. Conjunctions, [https://www.jsoftware.com/papers/APLDictionary1.htm#colon Custom]. APL Quote Quad, Volume 18, Number 1, 1987-09.</ref> and implemented in [[J]] (<source lang=j inline>!.</source>). | ||