HPL_dlocswpT(3)

💅 HPL_dlocswpT — the HPL Library Functions girlies know

okay so bestie, we're in the HPL_dlocswpT(3) page from the HPL Library Functions lineup, and honestly? it's giving "small but mighty." sit down, grab a strawberry 🍓, and let's get into it.

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✨ NAME ✨

HPL_dlocswpT — locally swaps rows within panel. that's it, that's the whole job, and she does it flawlessly 💅

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🌸 SYNOPSIS 🌸

#include "hpl.h"

void HPL_dlocswpT( HPL_T_panel * PANEL, const int II, const int JJ,
double * WORK );

look at that signature. clean. iconic. no notes. 👑

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🦋 DESCRIPTION 🦋

so HPL_dlocswpT performs the local swapping operations within a panel. that's the vibe.

and here's the little detail that matters, no cap: the lower triangular N0-by-N0 upper block of the panel is stored in transpose form. so like, don't come at her expecting the normal orientation, she's doing her own thing and she's thriving ✨

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🎀 ARGUMENTS 🎀

• PANEL — (local input/output) HPL_T_panel * — on entry, PANEL points to the data structure containing the panel information. she's the main character, everything routes through her 💖
• II — (local input) const int — on entry, II specifies the row offset where the column to be operated on starts with respect to the panel. so like, where in the rows are we, relative to the panel. iykyk 📍
• JJ — (local input) const int — on entry, JJ specifies the column offset where the column to be operated on starts with respect to the panel. the column coordinate bestie, panel-relative, keep up 🫶
• WORK — (local workspace) double * — on entry, WORK is a workarray of size at least 2 * (4+2*N0). and here's the full breakdown because she deserves the full breakdown:
  • WORK[0] contains the local maximum absolute value scalar
  • WORK[1] contains the corresponding local row index
  • WORK[2] contains the corresponding global row index
  • WORK[3] is the coordinate of process owning this max
  • the N0 length max row is stored in WORK[4:4+N0-1]
  • > note that this is also the JJth row (or column) of L1 👀
  • the remaining part of this array is used as workspace

so yeah, she's a whole setup. respect the workspace or perish 💀

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🌈 SEE ALSO 🌈

the whole friend group, fr fr — go say hi:

• HPL_dlocmax (3)
• HPL_dlocswpN (3)
• HPL_pdmxswp (3)
• HPL_pdpancrN (3)
• HPL_pdpancrT (3)
• HPL_pdpanllN (3)
• HPL_pdpanllT (3)
• HPL_pdpanrlN (3)
• HPL_pdpanrlT (3)
• HPL_pdrpancrN (3)
• HPL_pdrpancrT (3)
• HPL_pdrpanllN (3)
• HPL_pdrpanllT (3)
• HPL_pdrpanrlN (3)
• HPL_pdrpanrlT (3)
• HPL_pdfact (3)

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and that's the page bestie!! 💜 this whole thing is from HPL 2.2, dated February 24, 2016 — vintage but still eating, honestly. go swap those rows, you absolute icon 🌟🧚