slartg.f(3)

🌸 NAME 🌸

okay so this is slartg.f(3) from the LAPACK manual, section 3. She's that girl: a plane rotation with real cosine and real sine. Bestie, she's the slower, more accurate one, and she's about to explain herself 💅

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

subroutine slartg (F, G, CS, SN, R)

SLARTG generates a plane rotation with real cosine and real sine. periodt ✨

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💅 Function/Subroutine Documentation 💅

🧚 subroutine slartg (real F, real G, real CS, real SN, real R) 🧚

SLARTG generates a plane rotation with real cosine and real sine. no cap.

🎀 Purpose 🎀

SLARTG generates a plane rotation so that

   [  CS  SN  ]  .  [ F ]  =  [ R ]   where CS**2 + SN**2 = 1.
   [ -SN  CS  ]     [ G ]     [ 0 ]

That's the whole assignment: rotate the vector, keep the math cute, and remember CS**2 + SN**2 = 1. 💖

This is a slower, more accurate version of the BLAS1 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 without doing any floating point operations (saves work in SBDSQR when there are zeros on the diagonal).
• If F exceeds G in magnitude, CS will be positive.

🍓 Parameters 🍓

• F — REAL. The first component of vector to be rotated.
• G — REAL. The second component of vector to be rotated.
• CS — REAL. The cosine of the rotation.
• SN — REAL. The sine of the rotation.
• R — REAL. The nonzero component of the rotated vector.

🧵 thread-safety tea: 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.

🌈 Date 🌈

December 2016

Definition at line 99 of file slartg.f.

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⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole page, bestie 💖 source/version/date energy: LAPACK Version 3.8.0, Tue Nov 14 2017, for slartg.f(3). byeee 🫶✨