SORM2R(3)

💅 SORM2R(3) 💅

okay bestie, welcome to the LAPACK page for SORM2R(3) in the Library Functions Manual. It's giving unblocked-QR-reflector realness, and honestly? Iconic. 🫶

💖 NAME 💖

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/sorm2r.f

✨ SYNOPSIS ✨

🌈 Functions/Subroutines 🌈

• subroutine SORM2R (side, trans, m, n, k, a, lda, tau, c, ldc, work, info) — SORM2R multiplies a general matrix by the orthogonal matrix from a QR factorization determined by sgeqrf (unblocked algorithm).

🧚 Function/Subroutine Documentation 🧚

subroutine SORM2R (character side, character trans, integer m, integer n,
    integer k, real, dimension( lda, * ) a, integer lda, real, dimension( *
    ) tau, real, dimension( ldc, * ) c, integer ldc, real, dimension( * )
    work, integer info)

SORM2R multiplies a general matrix by the orthogonal matrix from a QR factorization determined by sgeqrf (unblocked algorithm).

🌸 Purpose 🌸

Okay so here's the vibe: SORM2R 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 SGEQRF. Q is of order m if SIDE = 'L' and of order n if SIDE = 'R'.

🎀 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**T (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 REAL 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 SGEQRF in the first k columns of its array argument A. A is modified by the routine but restored on exit.
• 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).
• TAU — TAU is REAL array, dimension (K); TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGEQRF.
• C — C is REAL 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 REAL 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 sorm2r.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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bye bestie 💖 this was LAPACK Version 3.12.0, footer source /home/abui...RC/sorm2r.f(3), and the footer didn't give a date — just source/version and vibes. Periodt. 💅✨