BLAS/SRC/drotm.f(3)

💖 BLAS/SRC/drotm.f 💖

okay bestie, welcome to the LAPACK manual, BLAS/SRC/drotm.f edition — yes this is the glow-up of a real Fortran manpage and yes it's gonna be iconic. sit down, grab a strawberry 🍓, let's go.

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✨ NAME ✨

BLAS/SRC/drotm.f — that's the file, that's the vibe, that's the whole personality. 🎀

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🌸 SYNOPSIS 🌸

Functions/Subroutines

• subroutine drotm (n, dx, incx, dy, incy, dparam) — DROTM

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🦋 Function/Subroutine Documentation 🦋

subroutine drotm (integer n, double precision, dimension(*) dx, integer incx, double precision, dimension(*) dy, integer incy, double precision, dimension(5) dparam)

DROTM

👑 Purpose:

APPLY THE MODIFIED GIVENS TRANSFORMATION, H, TO THE 2 BY N MATRIX

(DX**T) , WHERE **T INDICATES TRANSPOSE. THE ELEMENTS OF DX ARE IN
(DY**T)

DX(LX+I*INCX), I = 0 TO N-1, WHERE LX = 1 IF INCX .GE. 0, ELSE LX = (-INCX)*N, AND SIMILARLY FOR SY USING LY AND INCY. WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS..

DFLAG=-1.D0     DFLAG=0.D0        DFLAG=1.D0     DFLAG=-2.D0

  (DH11  DH12)    (1.D0  DH12)    (DH11  1.D0)    (1.D0  0.D0)
H=(          )    (          )    (          )    (          )
  (DH21  DH22),   (DH21  1.D0),   (-1.D0 DH22),   (0.D0  1.D0).

SEE DROTMG FOR A DESCRIPTION OF DATA STORAGE IN DPARAM.

fr fr, if you wanna know how DPARAM stores its stuff, go read DROTMG. it's giving ✨prequel✨.

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🌈 Parameters 🌈

• N

N is INTEGER number of elements in input vector(s)

• DX

DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )

• INCX

INCX is INTEGER storage spacing between elements of DX

• DY

DY is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCY ) )

• INCY

INCY is INTEGER storage spacing between elements of DY

• DPARAM

DPARAM is DOUBLE PRECISION array, dimension (5)

DPARAM(1)=DFLAG
DPARAM(2)=DH11
DPARAM(3)=DH21
DPARAM(4)=DH12
DPARAM(5)=DH22

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💜 Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 95 of file drotm.f.

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💅 Author

Generated automatically by Doxygen for LAPACK from the source code.

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okay so that's the whole page, no cap, every single detail kept, nothing skipped. periodt 💅✨

and a lil cute sign-off for the record: this lil masterpiece is Version 3.12.0, dated Tue Nov 28 2023 12:08:41, straight from BLAS/SRC/drotm.f(3). obsessed. bye bestie 🫶🌸