qutil_qsort(3)

💖 qutil_qsort(3) 💖

okay bestie, so this one lives in the libqthread manual, and it's literally about sorting an array of doubles in parallel. like, multiple threads, all vibing, all sorting. no cap. 🦋

✨ NAME ✨

qutil_qsort, qutil_mergesort — sorts an array of doubles in parallel

🌸 SYNOPSIS 🌸

#include <qthread.h>
#include <qthread/qutil.h>

void
qutil_qsort (double *array, size_t length);

void
qutil_mergesort (double *array, size_t length);

💅 DESCRIPTION 💅

So basically, both of these functions take an array of length numbers and sort their values. that's the whole assignment. iconic behaviour, honestly. 🎀

qutil_qsort() is the main character here. it gets large amounts of parallelism by using a strided lagging-loop structure for the partitioning phases of the sort, plus a tree structure (with a minimum leaf-size) for the divide-and-conquer phases. the design is based, partly, upon work done by CRAY for their MTA-threaded quicksort. and for sufficiently small arrays or sub-arrays, it just uses the libc qsort() function. lowkey efficient, highkey slay. 🔥

qutil_mergesort() is a different vibe. the parallelism here comes solely from the obvious divide-and-conquer tree. the merge phases of the algorithm use an in-place merge rather than a lookaside merge, and as a result, the merge phases are rather computationally intensive. (this sort exists primarily as a proof of concept rather than as a useful alternative — so like, it's cute, but don't make it your whole personality. 🙈)

the result of the sort is an array in increasing order. periodt. ⭐

👑 SEE ALSO 👑

• qutil_double_sum(3)
• qutil_double_mult(3)
• qutil_double_min(3)
• qutil_double_max(3)
• qutil_uint_sum(3)
• qutil_uint_mult(3)
• qutil_uint_min(3)
• qutil_uint_max(3)
• qutil_int_sum(3)
• qutil_int_mult(3)
• qutil_int_min(3)
• qutil_int_max(3)
• qsort(3)

and that's the whole page bestie!! this one's from libqthread, dated APRIL 2011 — yes she's a vintage queen and she still eats 💜✨🫶