SRC/slarf.f(3)

💅 SRC/slarf.f — like, the whole vibe

okay so bestie, welcome to the slarf manual page (it lives in the LAPACK library functions manual, section 3, and honestly? she's iconic). Buckle up, we're about to make linear algebra feel like a group chat. 🎀

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✨ SYNOPSIS ✨

🧚 Functions/Subroutines

• subroutine slarf (side, m, n, v, incv, tau, c, ldc, work) — SLARF applies an elementary reflector to a general rectangular matrix. that's the whole personality fr fr 💅

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🔥 Function/Subroutine Documentation 🔥

💖 subroutine slarf (character side, integer m, integer n, real, dimension( * ) v, integer incv, real tau, real, dimension( ldc, * ) c, integer ldc, real, dimension( * ) work)

SLARF applies an elementary reflector to a general rectangular matrix. periodt. ✨

🌸 Purpose:

!>
!> SLARF applies a real elementary reflector H to a real m by n matrix
!> C, from either the left or the right. H is represented in the form
!>
!>       H = I - tau * v * v**T
!>
!> where tau is a real scalar and v is a real vector.
!>
!> If tau = 0, then H is taken to be the unit matrix.
!>

so basically H is built from tau (a real scalar) and v (a real vector), and if tau = 0 then H just quietly becomes the unit matrix — no drama, no notes. 💀

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🦋 Parameters

• SIDE — SIDE is CHARACTER*1. it picks the side, obviously:

!>          = 'L': form  H * C
!>          = 'R': form  C * H
!>

• M — M is INTEGER, and it's the number of rows of the matrix C. that's it, that's the whole job. 🫶
• N — N is INTEGER, the number of columns of the matrix C. slay.
• V — V is REAL array, dimension:

!>                     (1 + (M-1)*abs(INCV)) if SIDE = 'L'
!>                  or (1 + (N-1)*abs(INCV)) if SIDE = 'R'

this is the vector v in the representation of H. important: V is not used if TAU = 0 — she's off duty in that case, respect it. 🙈

• INCV — INCV is INTEGER, the increment between elements of v. and INCV <> 0 — non-negotiable bestie, zero is not invited. ⭐
• TAU — TAU is REAL, the value tau in the representation of H. main character scalar energy. 👑
• C — C is REAL array, dimension (LDC,N).
  • On entry: the m by n matrix C.
  • On exit: C is overwritten by the matrix H * C if SIDE = 'L', or C * H if SIDE = 'R'.

so yeah, she gets replaced. no cap, that's literally the point. 🔥

• LDC — LDC is INTEGER, the leading dimension of the array C. and LDC >= max(1,M) — gotta hold that line, fr fr. 💜
• WORK — WORK is REAL array, dimension:

!>                         (N) if SIDE = 'L'
!>                      or (M) if SIDE = 'R'

the lil scratchpad. give her the room she needs. 🍓

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🌈 Author

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

look at that squad. genuinely obsessed. 🫶✨

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🎀 Definition at line 123 of file slarf.f.

(yeah, line 123 — cute number, no notes) 💅

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⭐ Author

Generated automatically by Doxygen for LAPACK from the source code. so like, a robot wrote this part, but we made it cute. 🤖💖

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🧚 and that's the whole page bestie! no skipped sections, no missing options, we kept every single detail because that's the vibe check and we passed it. 💅✨

okay bye, this was SRC/slarf.f(3) from LAPACK, Version 3.12.0 — catch you on the flip side! 🌸🦋💜