HPL_dlaswp02N(3)

💖 HPL_dlaswp02N — the pack-rows-into-columns girlie 💖

okay bestie, welcome to HPL_dlaswp02N, a real one from the HPL Library Functions lineup. This is the one that takes scattered rows of A and packs them, all cute and contiguous, into the workspace W. Row offsets in A? Specified by LINDXA. That's the whole vibe. 🎀

✨ SYNOPSIS ✨

#include "hpl.h"

void HPL_dlaswp02N( const int M, const int N, const double * A, const
int LDA, double * W0, double * W, const int LDW, const int * LINDXA,
const int * LINDXAU );

🌸 DESCRIPTION 🌸

So like, HPL_dlaswp02N packs scattered rows of an array A into the workspace W. The row offsets in A are specified by LINDXA. That's it, that's the job, and she does it flawlessly. 💅

👑 ARGUMENTS 👑

• M (local input) — const int On entry, M says how many rows of A should be copied into W. M must be at least zero. no negative nonsense pls 🙈
• N (local input) — const int On entry, N is the length of the rows of A that should be copied into W. N must be at least zero.
• A (local input) — const double * On entry, A points to an array of dimension (LDA,N). The rows of this array specified by LINDXA should be copied into W.
• LDA (local input) — const int On entry, LDA is the leading dimension of the array A. LDA must be at least MAX(1,M).
• W0 (local input/output) — double * On exit, W0 is an array of size (M-1)*LDW+1, that contains the destination offset in U where the columns of W should be copied. yeah she's input and output, main character energy fr 🫶
• W (local output) — double * On entry, W is an array of size (LDW,M). On exit, W contains the rows LINDXA[i] for i in [0..M) of A stored contiguously in W(:,i).
• LDW (local input) — const int On entry, LDW is the leading dimension of the array W. LDW must be at least MAX(1,N+1).
• LINDXA (local input) — const int * On entry, LINDXA is an array of dimension M that contains the local row indexes of A that should be copied into W.
• LINDXAU (local input) — const int * On entry, LINDXAU is an array of dimension M that contains the local row indexes of U that should be copied into A and replaced by the rows of W. the swap part of the saga, iykyk 😭

lowkey important: those minimum sizes on LDA and LDW are not suggestions bestie, they're the rules. LDA >= MAX(1,M) and LDW >= MAX(1,N+1), periodt.

🦋 SEE ALSO 🦋

the whole dlaswp cinematic universe, go read them all, they ate:

• HPL_dlaswp00N (3)
• HPL_dlaswp10N (3)
• HPL_dlaswp01N (3)
• HPL_dlaswp01T (3)
• HPL_dlaswp02N (3)
• HPL_dlaswp03N (3)
• HPL_dlaswp03T (3)
• HPL_dlaswp04N (3)
• HPL_dlaswp04T (3)
• HPL_dlaswp05N (3)
• HPL_dlaswp05T (3)
• HPL_dlaswp06N (3)
• HPL_dlaswp06T (3)

and that's the whole page bestie 💖 this iconic little number comes to you from HPL 2.2, dated February 24, 2016 — a certified classic, no cap. go pack some rows, you got this 🎀✨🦋