DORGR2(3)

💅 DORGR2(3) 💅

okay so welcome to DORGR2(3) from the Library Functions Manual, bestie 💖 — this is the LAPACK page about generating all or part of an orthogonal matrix Q, and yes, it's giving very much "linear algebra but make it cute." ✨

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dorgr2.f

That's literally the source file path, no cap. 🫶

🦋 SYNOPSIS 🦋

✨ Functions/Subroutines ✨

       subroutine DORGR2 (m, n, k, a, lda, tau, work, info)

DORGR2 generates all or part of the orthogonal matrix Q from an RQ factorization determined by sgerqf (unblocked algorithm). 💅

💖 Function/Subroutine Documentation 💖

   subroutine DORGR2 (integer m, integer n, integer k, double precision,
       dimension( lda, * ) a, integer lda, double precision, dimension( * )
       tau, double precision, dimension( * ) work, integer info)

DORGR2 generates all or part of the orthogonal matrix Q from an RQ factorization determined by sgerqf (unblocked algorithm). 🎀

🎀 Purpose: 🎀

DORGR2 generates an m by n real matrix Q with orthonormal rows, which is defined as the last m rows of a product of k elementary reflectors of order n:

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

as returned by DGERQF. ✨

🌸 Parameters 🌸

• M — INTEGER. The number of rows of the matrix Q. M >= 0. 💖
• N — INTEGER. The number of columns of the matrix Q. N >= M. 🦋
• K — INTEGER. The number of elementary reflectors whose product defines the matrix Q. M >= K >= 0. 🌸
• A — DOUBLE PRECISION array, dimension (LDA,N). On entry, the (m-k+i)-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by DGERQF in the last k rows of its array argument A. On exit, the m by n matrix Q. 💅
• LDA — INTEGER. The first dimension of the array A. LDA >= max(1,M). 🎀
• TAU — DOUBLE PRECISION array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGERQF. 🌈
• WORK — DOUBLE PRECISION array, dimension (M). 🧚
• INFO — INTEGER.
  • = 0: successful exit ✅
  • < 0: if INFO = -i, the i-th argument has an illegal value 😭

bestie, those constraints are not decorative — they're load-bearing. 🫶

👑 Author 👑

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

Definition at line 113 of file dorgr2.f.

💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the whole page, bestie! 💖 Footer check: LAPACK, Version 3.12.0, and the path /home/abui...RC/dorgr2.f(3) — that's the source/version sign-off (no date listed on this footer). periodt. 🫶✨