DORMR2(3)

🌈 DORMR2(3) — LAPACK Library Functions Manual, bestie edition 💅

✨ NAME ✨

Okay so this page is literally about /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dormr2.f, and the icon of the hour is DORMR2. No cap, that path is a whole journey. 🫶

🦋 SYNOPSIS 🦋

🎀 Functions/Subroutines 🎀

subroutine DORMR2 (side, trans, m, n, k, a, lda, tau, c, ldc, work,
    info)
    DORMR2 multiplies a general matrix by the orthogonal matrix from a
    RQ factorization determined by sgerqf (unblocked algorithm).

🌸 Function/Subroutine Documentation 🌸

Here’s the full signature, character for character, because we do not play about exact details:

subroutine DORMR2 (character side, character trans, integer m, integer n,
    integer k, double precision, dimension( lda, * ) a, integer lda, double
    precision, dimension( * ) tau, double precision, dimension( ldc, * ) c,
    integer ldc, double precision, dimension( * ) work, integer info)

DORMR2 multiplies a general matrix by the orthogonal matrix from a RQ factorization determined by sgerqf (unblocked algorithm). Slay, unblocked algorithm, we see you. ✨

💅 Purpose 💅

DORMR2 overwrites the general real m by n matrix C with:

• Q * C if SIDE = 'L' and TRANS = 'N', or
• Q**T* C if SIDE = 'L' and TRANS = 'T', or
• C * Q if SIDE = 'R' and TRANS = 'N', or
• C * Q**T if SIDE = 'R' and TRANS = 'T',

where Q is a real orthogonal matrix defined as the product of k elementary reflectors:

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

as returned by DGERQF. Q is of order m if SIDE = 'L' and of order n if SIDE = 'R'. Periodt. 💫

🍓 Parameters 🍓

• SIDE — SIDE is CHARACTER*1; = 'L': apply Q or Q**T from the Left; = 'R': apply Q or Q**T from the Right.
• TRANS — TRANS is CHARACTER*1; = 'N': apply Q (No transpose); = 'T': apply Q' (Transpose).
• M — M is INTEGER; the number of rows of the matrix C. M >= 0.
• N — N is INTEGER; the number of columns of the matrix C. N >= 0.
• 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.
• A — A is DOUBLE PRECISION array, dimension (LDA,M) if SIDE = 'L', (LDA,N) if SIDE = 'R'. The 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. A is modified by the routine but restored on exit. Iconic behavior, honestly.
• LDA — LDA is INTEGER; the leading dimension of the array A. LDA >= max(1,K).
• TAU — TAU is DOUBLE PRECISION array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGERQF.
• C — C is DOUBLE PRECISION array, dimension (LDC,N). On entry, the m by n matrix C. On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.
• LDC — LDC is INTEGER; the leading dimension of the array C. LDC >= max(1,M).
• WORK — WORK is DOUBLE PRECISION array, dimension (N) if SIDE = 'L', (M) if SIDE = 'R'.
• INFO — INFO is INTEGER; = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value.

👑 Author 👑

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

Definition at line 157 of file dormr2.f. 🎀

⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code. Doxygen really said “I’ll handle the paperwork, bestie.” 💖

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Okay that’s the whole page, bestie 💅 — source/version vibes are LAPACK, Version 3.12.0, and the footer path is /home/abui...RC/dormr2.f(3). There’s no date listed in the footer, so I’m not inventing one. 🌈✨