CUNM2L(3)

📦 version 3.12.0, in opensuse-leap 16.0

💅 CUNM2L (3) — like, the whole entire manual page, bestie

okay so real talk: this page lives at /home/abui...RC/cunm2l.f(3) and it's part of the LAPACK Library Functions Manual. yes, the LAPACK. the icon behavior. let's get into it 🫶

✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/cunm2l.f

that's the file, that's the whole name section, she's just a girl standing in front of a build path asking you to love her 💀 (it's the Fortran source for CUNM2L, iykyk)

🌸 SYNOPSIS 🌸

Functions/Subroutines

subroutine CUNM2L (side, trans, m, n, k, a, lda, tau, c, ldc, work,
    info)

CUNM2L multiplies a general matrix by the unitary matrix from a QL factorization determined by cgeqlf (unblocked algorithm). lowkey the whole plot right there ✨

🦋 Function/Subroutine Documentation 🦋

subroutine CUNM2L (character side, character trans, integer m, integer n,
    integer k, complex, dimension( lda, * ) a, integer lda, complex,
    dimension( * ) tau, complex, dimension( ldc, * ) c, integer ldc,
    complex, dimension( * ) work, integer info)

CUNM2L multiplies a general matrix by the unitary matrix from a QL factorization determined by cgeqlf (unblocked algorithm). no cap, that's the summary, and she's serving it twice because she can 💅

🎀 Purpose 🎀

!> !> CUNM2L overwrites the general complex m-by-n matrix C with !> !> Q * C if SIDE = 'L' and TRANS = 'N', or !> !> QH* C if SIDE = 'L' and TRANS = 'C', or !> !> C * Q if SIDE = 'R' and TRANS = 'N', or !> !> C * QH if SIDE = 'R' and TRANS = 'C', !> !> where Q is a complex unitary matrix defined as the product of k !> elementary reflectors !> !> Q = H(k) . . . H(2) H(1) !> !> as returned by CGEQLF. Q is of order m if SIDE = 'L' and of order n !> if SIDE = 'R'. !>

so basically C gets completely overwritten (rip to whatever was in there before, she did NOT survive 🙈) and Q is out here being a product of k elementary reflectors, in that exact order Q = H(k) . . . H(2) H(1), straight from CGEQLF. and Q's order? m if SIDE = 'L', n if SIDE = 'R'. main character energy depending on which side she's on 👑

🌈 Parameters 🌈

  • SIDE — SIDE is CHARACTER*1. = 'L': apply Q or Q**H from the Left. = 'R': apply Q or Q**H from the Right. pick a side, bestie, it's giving left-vs-right discourse ⭐
  • TRANS — TRANS is CHARACTER*1. = 'N': apply Q (No transpose). = 'C': apply Q**H (Conjugate transpose). nah because the conjugate transpose is right there 🦋
  • M — M is INTEGER. The number of rows of the matrix C. M >= 0. rows, periodt.
  • N — N is INTEGER. The number of columns of the matrix C. N >= 0. columns, also periodt.
  • K — K is INTEGER. The number of elementary reflectors whose product defines the matrix Q. If SIDE = 'L', M >= K >= 0; if SIDE = 'R', N >= K >= 0. so K's limits are literally side-dependent, respect the boundaries 😌
  • A — A is COMPLEX array, dimension (LDA,K). The i-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGEQLF in the last k columns of its array argument A. A is modified by the routine but restored on exit. ok so she borrows your array, ✨ rearranges it ✨, and puts it back. iconic, courteous, no notes 💖
  • LDA — LDA is INTEGER. The leading dimension of the array A. If SIDE = 'L', LDA >= max(1,M); if SIDE = 'R', LDA >= max(1,N). don't fumble the leading dimension, it WILL notice 💀
  • TAU — TAU is COMPLEX array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGEQLF. one scalar factor per reflector, she's organized like that 🎀
  • C — C is COMPLEX array, dimension (LDC,N). On entry, the m-by-n matrix C. On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q. entry vs exit, glow-up arc, we love a transformation 🌸
  • LDC — LDC is INTEGER. The leading dimension of the array C. LDC >= max(1,M). yes it's M here, not N, don't come for me, that's what it says 🫶
  • WORK — WORK is COMPLEX array, dimension (N) if SIDE = 'L', (M) if SIDE = 'R'. scratch space that switches sizes based on the side. she's flexible ✨
  • INFO — INFO is INTEGER. = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value. so if INFO comes back negative, that's the universe telling you argument number i was a little chaotic 🙈

👑 Author 👑

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

four legends, one subroutine. ate and left no crumbs 🔥

⭐ Definition ⭐

Definition at line 157 of file cunm2l.f. that's the exact line, go look, i'll wait 💅

💜 Author (the meta one) 💜

Generated automatically by Doxygen for LAPACK from the source code. not a human, just a very diligent little documentation machine 🧚

okay that's the whole page, nothing skipped, nothing merged, all facts intact — and to close out: this beauty is LAPACK Version 3.12.0, dated to that same /home/abui...RC/cunm2l.f(3) footer energy. bye bestie, go multiply something 💖✨🎀

📦 where this page comes from