SRC/dlarz.f(3)

💅 SRC/dlarz.f(3) — Library Functions Manual ✨

okay so bestie, this is the SRC/dlarz.f(3) page from the Library Functions Manual, and it’s all about DLARZ doing reflector things. no cap, every fact stays exactly where it was. 🫶

NAME 💖

SRC/dlarz.f

SYNOPSIS 🌸

Functions/Subroutines 🎀

• subroutine dlarz (side, m, n, l, v, incv, tau, c, ldc, work) — DLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.

Function/Subroutine Documentation 💖

Here’s the full signature, exactly as written:

subroutine dlarz (character side, integer m, integer n, integer l, double
       precision, dimension( * ) v, integer incv, double precision tau, double
       precision, dimension( ldc, * ) c, integer ldc, double precision,
       dimension( * ) work)

DLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix.

Purpose 🔥

DLARZ 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.

H is a product of k elementary reflectors as returned by DTZRZF.

Parameters 🧚

• SIDE — SIDE is CHARACTER*1
  • = 'L': form H * C
  • = 'R': form C * H
• M — M is INTEGER The number of rows of the matrix C.
• N — N is INTEGER The number of columns of the matrix C.
• L — L is INTEGER The number of entries of the vector V containing the meaningful part of the Householder vectors. If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
• V — V is DOUBLE PRECISION array, dimension (1+(L-1)*abs(INCV)) The vector v in the representation of H as returned by DTZRZF. V is not used if TAU = 0.
• INCV — INCV is INTEGER The increment between elements of v. INCV <> 0.
• TAU — TAU is DOUBLE PRECISION The value tau in the representation of H.
• C — C is DOUBLE PRECISION 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'.
• LDC — LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M).
• WORK — WORK is DOUBLE PRECISION array, dimension (N) if SIDE = 'L' or (M) if SIDE = 'R'

Author 🌈

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

Contributors: 🍓

• A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA

Further Details: 🦋

The source has an empty !> block here — no extra details, bestie. That’s the whole vibe. 💀

Definition at line 144 of file dlarz.f.

Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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okayyy that’s the page 💖 the footer vibes are LAPACK, Version 3.12.0, and page SRC/dlarz.f(3). date? nope, the original footer doesn’t have one, and I’m not inventing one, bestie. byeee 🎀✨