lartgp(3)

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version 3.12.1 · 9 versions
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🎀 lartgp(3) — Library Functions Manual 🎀

okay so bestie, welcome to the lartgp(3) page. It's giving two Fortran subroutines that generate plane rotations, and they're the more accurate-but-slower besties of the BLAS rot routines. No cap. 💅

🌸 NAME 🌸

lartgp — lartgp: generate plane rotation, more accurate than BLAS rot

✨ SYNOPSIS ✨

💅 Functions

  • subroutine dlartgp (f, g, cs, sn, r) — DLARTGP generates a plane rotation so that the diagonal is nonnegative.
  • subroutine slartgp (f, g, cs, sn, r) — SLARTGP generates a plane rotation so that the diagonal is nonnegative.

🔥 Detailed Description 🔥

This page is the home of both subroutines. The full function tea is in the next section. Scroll down, bestie. 🫶

🫶 Function Documentation 🫶

💖 subroutine dlartgp (double precision f, double precision g, double precision cs, double precision sn, double precision r)

DLARTGP generates a plane rotation so that the diagonal is nonnegative. Periodt.

🌟 Purpose

!> DLARTGP 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 DROTG,
!> 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.
!>

🎀 Parameters

  • F — F is DOUBLE PRECISION. The first component of vector to be rotated.
  • G — G is DOUBLE PRECISION. The second component of vector to be rotated.
  • CS — CS is DOUBLE PRECISION. The cosine of the rotation.
  • SN — SN is DOUBLE PRECISION. The sine of the rotation.
  • R — R is DOUBLE PRECISION. The nonzero component of the rotated vector.
This version has a few statements commented out for thread safety (machine parameters are computed on each entry). 10 feb 03, SJH.

👑 Author

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

📍 Definition

Definition at line 94 of file dlartgp.f.

💖 subroutine slartgp (real f, real g, real cs, real sn, real r)

SLARTGP generates a plane rotation so that the diagonal is nonnegative. Iconic behavior, honestly. 💅

🌟 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.
!>

🎀 Parameters

  • F — F is REAL. The first component of vector to be rotated.
  • G — G is REAL. The second component of vector to be rotated.
  • CS — CS is REAL. The cosine of the rotation.
  • SN — SN is REAL. The sine of the rotation.
  • R — R is REAL. The nonzero component of the rotated vector.
This version has a few statements commented out for thread safety (machine parameters are computed on each entry). 10 feb 03, SJH.

👑 Author

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

📍 Definition

Definition at line 94 of file slartgp.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

source/version sign-off, bestie: this is LAPACK, Version 3.12.0, on the lartgp(3) page — and the footer has no date listed, so no invented date, bestie. Byeee! 🎀💖

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