SRC/sorgl2.f(3)

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version 3.12.1 · 4 versions
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💖 SRC/sorgl2.f 💖

okay so this is the Library Functions Manual page for SRC/sorgl2.f, and bestie, it's a whole little LAPACK moment. We're talking about SORGL2 and its whole reflector-era vibe. Let's get into it. 🦋

🌸 SYNOPSIS 🌸

🌼 Functions/Subroutines 🌼

  • subroutine sorgl2 (m, n, k, a, lda, tau, work, info) — SORGL2, literally the main character of this page.

🧚 Function/Subroutine Documentation 🧚

subroutine sorgl2 (integer m, integer n, integer k, real, dimension( lda, *
       ) a, integer lda, real, dimension( * ) tau, real, dimension( * ) work,
       integer info)

SORGL2 — yes, that's the name, no cap.

💫 Purpose 💫

SORGL2 generates an m by n real matrix Q with orthonormal rows, which is defined as the first m rows of a product of k elementary reflectors of order n
      Q  =  H(k) . . . H(2) H(1)
as returned by SGELQF.

It's giving reflector chain realness, and the Q is the moment. ✨

🎀 Parameters 🎀

  • M — M is INTEGER. The number of rows of the matrix Q. Constraint: M >= 0. Respect the row count, bestie. 💅
  • N — N is INTEGER. The number of columns of the matrix Q. Constraint: N >= M. The columns gotta cover the rows, periodt.
  • K — K is INTEGER. The number of elementary reflectors whose product defines the matrix Q. Constraint: M >= K >= 0. This is the reflector count, and it stays in its lane.
  • A — A is REAL array, dimension (LDA,N). On entry, the i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by SGELQF in the first k rows of its array argument A. On exit, the m-by-n matrix Q. So A walks in as reflector data and leaves as the whole Q. Iconic transformation, honestly. 🦋
  • LDA — LDA is INTEGER. The first dimension of the array A. Constraint: LDA >= max(1,M). Respect the leading dimension, fr fr.
  • TAU — TAU is REAL array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGELQF. The reflector's little scalar bestie. 🎀
  • WORK — WORK is REAL array, dimension (M). Workspace, doing its quiet background-support thing. 🫶
  • INFO — INFO is INTEGER.
    • = 0: successful exit. Slay. ✅
    • < 0: if INFO = -i, the i-th argument has an illegal value. That's the illegal-argument alarm, and it's not cute. 😭

👑 Author 👑

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

Definition at line 112 of file sorgl2.f.

🦋 Author 🦋

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byeee 💖 this page came from LAPACK, Version 3.12.0, and its little source tag is SRC/sorgl2.f(3) — okay that's the whole manual page, bestie, we ate and left no crumbs. 🍓✨

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