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in reply to Re^2: Understanding the Schwartzian transform.
in thread Understanding the Schwartzian transform.

Is this the canonical form of the Schwartzian Transform or a variant?

Yes, it can be considered as the canonical form of the Schwartzian Transform. The original ST that appeared in a newsgroup more than 15 years ago might not have worked on fila age (I don't remember), but, definitely, the "output_array = map {block} sort {block} map {block} input array" is the canonical form of the Schwartzian Transform.

  • Comment on Re^3: Understanding the Schwartzian transform.

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Re^4: Understanding the Schwartzian transform.
by Anonymous Monk on Jul 22, 2013 at 08:03 UTC

    but, definitely, the "output_array = map {block} sort {block} map {block} input array" is the canonical for of the Schwartzian Transform.

    Sorry, that is like the generic form of Guttman-Rosler Transforms (see links) except without the secret ingredient :)(normalize/restore)

    Schwartzian is 

    my @sorted = map  { restore_from_cache    }
             sort { by_cached_expensive   }
             map  { store_cache_expensive } @original;

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[d/l]

      Sorry, but except that I did not detail what goes into the code blocks (as this has been detailed well enough the the previous posts), I do not see any difference between your version of the Schwartzian Transform and mine.

[reply]
        Because in GRT, you just change the data so they can be sorted lexicographically as strings, while in Schwartzian transform, you create a structure. You can simplify both to map {} sort {} map {} list (in GRT, sort block can be omitted), their difference can be seen only if you give more details.
        لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
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