HPL_dlocmax(3)

💖 HPL_dlocmax — bestie edition 💖

okay so this is a page from the HPL library functions manual (that's the HPL Library Functions section, for the record), and today's main character is HPL_dlocmax(3). sit down, grab a boba, we're finding maximums 🍓

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✨ NAME ✨

HPL_dlocmax — finds the maximum entry in matrix column. that's it, that's the whole job, and she does it flawlessly 💅

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🦋 SYNOPSIS 🦋

#include "hpl.h"

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

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🌸 DESCRIPTION 🌸

so HPL_dlocmax finds the maximum entry in the current column and packs all the useful info into WORK[0:3]. no cap, that's the whole vibe. ✨

on exit, here's what's in your workarray:

• WORK[0] — the local maximum absolute value scalar
• WORK[1] — the corresponding local row index
• WORK[2] — the corresponding global row index
• WORK[3] — the coordinate of the process owning this max 👑

and when N is less than 1? she doesn't crash out, she just initializes WORK[0:2] to zero, and sets WORK[3] to the total number of process rows. iconic behavior honestly. 🫶

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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 whole context bestie, treat her with respect 💜
• N (local input) — const int on entry, N specifies the local number of rows of the column of A on which we operate.
• 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.
• 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.
• WORK (local workspace) — double * on entry, WORK is a workarray of size at least 4. on exit:
  • 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 🌈

fr fr, make that workarray at least size 4. she's not asking, she's telling. 😭

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👑 SEE ALSO 👑

the whole friend group, all slaying in their own lanes:

• HPL_dlocswpN (3)
• HPL_dlocswpT (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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that's the page bestie, you ate 💅✨

HPL 2.2 — dated February 24, 2016 — mwah, thanks for reading, ily, go find your maximum 🦋💖