Re: Sorting implemented in Guile standard library

[Zelphir Kaltstahl <zelphirkaltstahl@posteo.de>]

Hello Bill!

Thanks for looking into it!

Regards,
Zelphir

On 16.08.20 23:11, Bill Markmann wrote:
> I'm not a guile hacker, but looking at the source for
> "libguile/sort.c", it looks like quicksort:
>
> #include "sort.h"
>
> /* We have two quicksort variants: one for SCM (#t) arrays and one for
>    typed arrays.
> */
>
> #define NAME        quicksort
> #define INC_PARAM   ssize_t inc,
> #define VEC_PARAM   SCM * ra,
> #define GET(i)      ra[(i)*inc]
> #define SET(i, val) ra[(i)*inc] = val
> #include "quicksort.i.c"
>
> The sort functions look like they
> call "s_scm_restricted_vector_sort_x", and then in there:
>
>   if (handle.element_type == SCM_ARRAY_ELEMENT_TYPE_SCM)
>     quicksort (scm_array_handle_writable_elements (&handle) -
> dims[0].lbnd * dims[0].inc,
>                spos, epos, dims[0].inc, less);
>   else
>     quicksorta (&handle, spos, epos, less);
>
>
> I'd assume that's what is underneath (sort items less) and friends. 
> Just a guess, though... :-)
>
>
> On Sun, Aug 16, 2020 at 4:56 PM Zelphir Kaltstahl
> <zelphirkaltstahl@posteo.de <mailto:zelphirkaltstahl@posteo.de>> wrote:
>
>     Hello Guile Users!
>
>     I was checking out
>     https://www.gnu.org/software/guile/manual/html_node/Sorting.html and
>     noticed, that the definition of `sort` does not mention, which
>     algorithm
>     is used for sorting:
>
>     > Sort the sequence items, which may be a list or a vector. less
>     is used
>     for comparing the sequence elements. This is not a stable sort.
>
>     So my question is: Which algorithm is used for Guile's `sort`
>     function?
>
>     Regards,
>     Zelphir
>
>     -- 
>     repositories: https://notabug.org/ZelphirKaltstahl
>
>
-- 
repositories: https://notabug.org/ZelphirKaltstahl