SRC/sorg2l.f(3)

💖 NAME 💖

SRC/sorg2l.f — okay bestie, this is the page for SRC/sorg2l.f(3) in the Library Functions Manual. It's giving serious LAPACK subroutine energy, and we're gonna get through it together. 💅✨

✨ SYNOPSIS ✨

🎀 Functions/Subroutines

• subroutine sorg2l (m, n, k, a, lda, tau, work, info) — SORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm).

🦋 Function/Subroutine Documentation 🦋

⭐ subroutine sorg2l (integer m, integer n, integer k, real, dimension( lda, * ) a, integer lda, real, dimension( * ) tau, real, dimension( * ) work, integer info)

SORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm). Periodt.

💜 Purpose:

Okay so here's the tea: SORG2L generates an m by n real matrix Q with orthonormal columns, and Q is defined as the last n columns of a product of k elementary reflectors of order m, like this:

Q  =  H(k) . . . H(2) H(1)

as returned by SGEQLF. No cap, that's the whole purpose. 🫶

🌸 Parameters

• M — M is INTEGER. It's the number of rows of the matrix Q. M >= 0. Vibe check: nonnegative.
• N — N is INTEGER. It's the number of columns of the matrix Q. M >= N >= 0.
• K — K is INTEGER. It's the number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.
• A — A is REAL array, dimension (LDA,N). On entry, the (n-k+i)-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by SGEQLF in the last k columns of its array argument A. On exit, the m by n matrix Q. She transforms on exit, icon behavior. 🦋
• LDA — LDA is INTEGER. It's the first dimension of the array A. LDA >= max(1,M).
• TAU — TAU is REAL array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGEQLF.
• WORK — WORK is REAL array, dimension (N). Short and sweet, like a good group chat reply.
• INFO — INFO is INTEGER. = 0: successful exit. < 0: if INFO = -i, the i-th argument has an illegal value. Bestie, negative INFO means somebody passed something illegal — pay attention. 💀

👑 Author

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

Definition at line 113 of file sorg2l.f. Noted, saved, screenshotted. 📌

💅 Author 💅

Generated automatically by Doxygen for LAPACK from the source code. It's automated, it's iconic, it's doing its thing. ✨

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🎀 That's the whole vibe, bestie: this is SRC/sorg2l.f(3), the footer says LAPACK, Version 3.12.0, and honestly? She ate. Go slay your QL factorization era. 💖🌈👑