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Inner Product: Difference between revisions
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mention monadic inner product
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The <syntaxhighlight lang=apl>⊃⍤0⊢(↓⍺)∘.(⍺⍺/⍵⍵¨)↓(¯1⌽⍳⍴⍴⍵)⍉⍵</syntaxhighlight> line of IP above can be rewritten as <syntaxhighlight lang=apl>⍺(⍺⍺⌿⍵⍵¨⍤¯1)⍤1 99⊢⍵</syntaxhighlight> which uses the more efficient major-cell-at-a-time algorithm (rather than row-by-column). The ISO/IEC 13751:2001(E) inner product, conversely, can only be calculated row-by-column, as computing the results one major cell (of the right argument) at a time relies on each application of the right operand being done between two scalars and producing a scalar result. | The <syntaxhighlight lang=apl>⊃⍤0⊢(↓⍺)∘.(⍺⍺/⍵⍵¨)↓(¯1⌽⍳⍴⍴⍵)⍉⍵</syntaxhighlight> line of IP above can be rewritten as <syntaxhighlight lang=apl>⍺(⍺⍺⌿⍵⍵¨⍤¯1)⍤1 99⊢⍵</syntaxhighlight> which uses the more efficient major-cell-at-a-time algorithm (rather than row-by-column). The ISO/IEC 13751:2001(E) inner product, conversely, can only be calculated row-by-column, as computing the results one major cell (of the right argument) at a time relies on each application of the right operand being done between two scalars and producing a scalar result. | ||
Some implementations extend the inner product by implementing Iverson's monadic variant<ref>https://www.jsoftware.com/papers/satn42.htm</ref>, which takes a single argument and performs the operation of computing the alternant, as modelled by [https://dfns.dyalog.com/n_alt.htm dfns.alt]. | |||
== External links == | == External links == | ||