Performance: Difference between revisions

Performance (view source)

320 bytes added , 18:44, 9 November 2020

→‎Alternate array representations: Avoid implying ngn/apl uses strides

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 === Alternate array representations ===
-Internally, APL arrays are usually stored as two lists in memory. The first is a list of the shape (although some implementations also include the "stride"<ref>Nick Nickolov ''Compiling APL to JavaScript'' (Vector Volume 26)</ref>). The second is the ravel of elements in the array. Nested arrays consist of pointers to arrays which may be distributed across memory, their use can lead to very inefficient memory read patterns - in contrast to flat arrays which are stored as a contiguous block.
+Internally, APL arrays are usually stored as two lists in memory. The first is a list of the shape (although it's also possible to store the "stride", enabling different views of the same data<ref>NumPy Reference. [https://numpy.org/doc/stable/reference/generated/numpy.ndarray.strides.html "ndarray.strides"]. Accessed 2020-11-09.</ref><ref>[[Nick Nickolov]]. [http://archive.vector.org.uk/art10501160 "Compiling APL to JavaScript"]. [[Vector Journal]] Volume 26 No. 1. 2013-09. (The strided representation was later removed from [[ngn/apl]].)</ref>). The second is the ravel of elements in the array. Nested arrays consist of pointers to arrays which may be distributed across memory, their use can lead to very inefficient memory read patterns - in contrast to flat arrays which are stored as a contiguous block.
 === Reference counting and data reuse ===