/home/abui.../slartgp.f(3)

🌸 SLARTGP — the rotation glow-up page 🌸

ok so this is the manual page for slartgp.f(3), straight out of the Library Functions Manual, and honestly? she's a little icon. let's get into it 💅

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✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/slartgp.f

like, yes bestie, that's the whole name. it's that girl with the full government name energy 🎀

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🦋 SYNOPSIS 🦋

Functions/Subroutines

• subroutine SLARTGP (f, g, cs, sn, r) — SLARTGP generates a plane rotation so that the diagonal is nonnegative. lowkey iconic behavior, ngl ✨

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👑 Function/Subroutine Documentation 👑

subroutine SLARTGP (real f, real g, real cs, real sn, real r)

SLARTGP generates a plane rotation so that the diagonal is nonnegative. periodt. 💖

🧚 Purpose:

!>
!> SLARTGP generates a plane rotation so that
!>
!>    [  CS  SN  ]  .  [ F ]  =  [ R ]   where CS**2 + SN**2 = 1.
!>    [ -SN  CS  ]     [ G ]     [ 0 ]
!>
!> This is a slower, more accurate version of the Level 1 BLAS routine SROTG,
!> with the following other differences:
!>    F and G are unchanged on return.
!>    If G=0, then CS=(+/-)1 and SN=0.
!>    If F=0 and (G .ne. 0), then CS=0 and SN=(+/-)1.
!>
!> The sign is chosen so that R >= 0.
!>

ok so real talk — she does the exact same rotation job as SROTG but she takes her time, she's the slower and more accurate one. it's giving "I don't rush, I arrive" 🫶

and the differences, spelled out so nobody gets confused:

• F and G come back unchanged on return — not me noticing they're untouched, slay 🙈
• If G=0, then CS=(+/-)1 and SN=0
• If F=0 and (G .ne. 0), then CS=0 and SN=(+/-)1
• and the sign is chosen so that R >= 0 — nonnegativity supremacy 👑

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🌈 Parameters

• F — F is REAL, and it's the first component of the vector to be rotated. the main character of the pair ✨
• G — G is REAL, the second component of the vector to be rotated. supporting role but she's serving 💅
• CS — CS is REAL, the cosine of the rotation. cos queen 🌸
• SN — SN is REAL, the sine of the rotation. sin queen, matching set 🎀
• R — R is REAL, the nonzero component of the rotated vector. the payoff, the finale, the moment 🔥

ngl there's a note tucked in here and it matters: this version has a few statements commented out for thread safety (machine parameters are computed on each entry). 10 feb 03, SJH. 🫡 so yes, she recomputes stuff every single time and that's on purpose, bestie, don't come for her.

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💜 Author

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

four whole institutions, it's giving collaborative slay 👯‍♀️

Definition at line 94 of file slartgp.f.

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⭐ Author (again, yes really) ⭐

Generated automatically by Doxygen for LAPACK from the source code. so nobody hand-wrote this page, a robot did, and honestly the robot ate 🤖✨

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ok bye bestie, go rotate something 💖

LAPACK — Version 3.12.0 🌈 and this whole thing lives at /home/abui.../slartgp.f(3), mwah 😘 🦋