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

📦 version 3.12.0, in opensuse-leap 16.0

🌟 NAME 🌟

okay so bestie, this is the dlartgs.f(3) page from the Library Functions Manual, and it's serving pure LAPACK realness ✨. The path it lives at is:

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

🧚 SYNOPSIS 🧚

🎀 Functions/Subroutines 🎀

subroutine DLARTGS (x, y, sigma, cs, sn)
    DLARTGS generates a plane rotation designed to introduce a bulge in
    implicit QR iteration for the bidiagonal SVD problem.

🦋 Function/Subroutine Documentation 🦋

💫 subroutine DLARTGS 💫

subroutine DLARTGS (double precision x, double precision y, double precision
    sigma, double precision cs, double precision sn)

DLARTGS generates a plane rotation designed to introduce a bulge in implicit QR iteration for the bidiagonal SVD problem. iconic behavior, no cap 💅

✨ Purpose ✨

okay so here's the whole vibe: DLARTGS generates a plane rotation designed to introduce a bulge in Golub-Reinsch-style implicit QR iteration for the bidiagonal SVD problem. X and Y are the top-row entries, and SIGMA is the shift. The computed CS and SN define a plane rotation satisfying

   [  CS  SN  ]  .  [ X^2 - SIGMA ]  =  [ R ],
   [ -SN  CS  ]     [    X * Y    ]     [ 0 ]

with R nonnegative. If X^2 - SIGMA and X * Y are 0, then the rotation is by PI/2. periodt. 💖

🌸 Parameters 🌸

  • X — X is DOUBLE PRECISION. It's the (1,1) entry of an upper bidiagonal matrix. slay.
  • Y — Y is DOUBLE PRECISION. It's the (1,2) entry of an upper bidiagonal matrix. 💫
  • SIGMA — SIGMA is DOUBLE PRECISION. It's the shift. 🎀
  • CS — CS is DOUBLE PRECISION. It's the cosine of the rotation. 🌈
  • SN — SN is DOUBLE PRECISION. It's the sine of the rotation. 🦋

💌 Author 💌

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

📍 Definition 📍

Definition at line 89 of file dlartgs.f. 🫶

🫶 Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

💖 cute little sign-off bestie: LAPACK, Version 3.12.0, page path /home/abui.../dlartgs.f(3) — byeee, go slay those rotations 🌸💅

📦 where this page comes from