SRC/zlarz.f(3)

💖 SRC/zlarz.f(3) 💖

okay so this page is from the Library Functions Manual, and the star of the show is SRC/zlarz.f. It’s giving “subroutine documentation but make it cute,” and we are seated. 🎀

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✨ NAME ✨

SRC/zlarz.f — the page name, bestie. This one is all about zlarz.

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🌸 SYNOPSIS 🌸

🫶 Functions/Subroutines 🫶

• subroutine zlarz (side, m, n, l, v, incv, tau, c, ldc, work) — ZLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix. no cap, that’s the whole vibe. 💅

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💖 Function/Subroutine Documentation 💖

Here’s the full signature, exactly as it is, because we do not play about exact details:

subroutine zlarz (character side, integer m, integer n, integer l,
    complex*16, dimension( * ) v, integer incv, complex*16 tau, complex*16,
    dimension( ldc, * ) c, integer ldc, complex*16, dimension( * ) work)

ZLARZ applies an elementary reflector (as returned by stzrzf) to a general matrix. icon behavior, honestly. ✨

🦋 Purpose 🦋

ZLARZ applies a complex elementary reflector H to a complex M-by-N matrix C, from either the left or the right. H is represented in the form:

H = I - tau * v * v**H

where tau is a complex scalar and v is a complex vector.

If tau = 0, then H is taken to be the unit matrix. simple as that.

To apply H**H (the conjugate transpose of H), supply conjg(tau) instead of tau.

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

🎀 Parameters 🎀

• SIDE — CHARACTER*1
  • = 'L': form H * C
  • = 'R': form C * H
• M — INTEGER
  • The number of rows of the matrix C.
• N — INTEGER
  • The number of columns of the matrix C.
• L — 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 — COMPLEX*16 array, dimension (1+(L-1)*abs(INCV))
  • The vector v in the representation of H as returned by ZTZRZF.
  • V is not used if TAU = 0.
• INCV — INTEGER
  • The increment between elements of v. INCV <> 0.
• TAU — COMPLEX*16
  • The value tau in the representation of H.
• C — COMPLEX*16 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 — INTEGER
  • The leading dimension of the array C. LDC >= max(1,M).
• WORK — COMPLEX*16 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 🦋

This section is literally just:

!>

That’s it. that’s the whole further details moment. 💀

Definition at line 146 of file zlarz.f.

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📚 Author 📚

Generated automatically by Doxygen for LAPACK from the source code.

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Kisses and sparkles, bestie: LAPACK, Version 3.12.0, for SRC/zlarz.f(3). The footer has no date, so I’m not inventing one — fr fr, we keep the facts exact. 💖✨🎀