HPL_all_reduce(3)

💖 HPL_all_reduce(3) 💖

okay so bestie, welcome to HPL_all_reduce, a function from the HPL library (that's HPL Library Functions, for the record) and it's literally about to become your new fave. this is a manpage. yes a real one. no cap. let's get into it 🫶

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✨ NAME ✨

HPL_all_reduce — All reduce operation. that's the whole name. short, sweet, iconic 👑

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🌸 SYNOPSIS 🌸

#include "hpl.h"

int HPL_all_reduce( void * BUFFER, const int COUNT, const HPL_T_TYPE
DTYPE, const HPL_T_OP OP, MPI_Comm COMM );

look at that signature. chef's kiss. 💅

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🦋 DESCRIPTION 🦋

HPL_all_reduce performs a global reduce operation across all processes of a group, and — this is the good part — it leaves the results on all processes. not just one lucky winner. everybody eats. 🍓✨

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🎀 ARGUMENTS 🎀

• BUFFER — (local input/global out void * — On entry, BUFFER points to the buffer to be combined. On exit, this array contains the combined data and is identical on all processes in the group. so like, everyone ends up matching. friendship bracelets fr fr. 🫶
• COUNT — (global input) const int — On entry, COUNT indicates the number of entries in BUFFER. COUNT must be at least zero. (yes, zero is allowed. negative? absolutely not, don't even try it 😭)
• DTYPE — (global input) const HPL_T_TYPE — On entry, DTYPE specifies the type of the buffers operands. tell it what kind of data you're working with, bestie. it needs to know. 🌈
• OP — (global input) const HPL_T_OP — On entry, OP is a pointer to the local combine function. this is the little guy that does the actual combining. main character energy, honestly. ⭐
• COMM — (global/local input) MPI_Comm — The MPI communicator identifying the process collection. it's the group chat. who's in it. who's getting the results. all of that. 💬

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👑 SEE ALSO 👑

HPL_broadcast (3), HPL_reduce (3), HPL_barrier (3), HPL_min (3), HPL_max (3), HPL_sum (3).

go read those too, they're all part of the same little squad and they're all lowkey serving 🔥

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and that's the whole page, bestie!! this was HPL 2.2, dated February 24, 2016 — written by the HPL Library Functions girlies, and yeah, the version is old but it ATE and it's still iconic. k bye, go reduce something globally 💜✨🎀