SORMR2(3)

💅 SORMR2(3) 💅

okay so bestie, this page comes straight outta the Library Functions Manual and lives at

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/sormr2.f

and honestly? it's giving ✨ linear algebra royalty ✨. let's get into it 🫶

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✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/sormr2.f

that's the file, that's the whole name section, it's literally just the path and we respect it 😌

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🦋 SYNOPSIS 🦋

Functions/Subroutines

subroutine SORMR2 (side, trans, m, n, k, a, lda, tau, c, ldc, work,
    info)

SORMR2 multiplies a general matrix by the orthogonal matrix from a RQ factorization determined by sgerqf (unblocked algorithm). no cap, that's the whole vibe 🔥

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🌸 Function/Subroutine Documentation 🌸

subroutine SORMR2 (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)

SORMR2 multiplies a general matrix by the orthogonal matrix from a RQ factorization determined by sgerqf (unblocked algorithm). she's iconic, she's unblocked, she's here 💅

🎀 Purpose 🎀

SORMR2 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 SGERQF. and like, Q is of order m if SIDE = 'L' and of order n if SIDE = 'R'. remember that, it comes up 🧚

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💖 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 REAL 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 SGERQF in the last k rows of its array argument A.

⚠️ heads up bestie: A is modified by the routine but restored on exit. so she goes on a little journey and comes back exactly the same, we love a round trip 😭

• LDA — LDA is INTEGER. the leading dimension of the array A. LDA >= max(1,K).
• TAU — TAU is REAL array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGERQF.
• 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 💀

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👑 Author 👑

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

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⭐ Definition at line 157 of file sormr2.f. ⭐

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🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. (yes the page has two Author sections, no we're not asking questions, we're just matching the energy 🎀)

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and that's the whole page bestie!! shoutout to LAPACK, Version 3.12.0, over at /home/abui...RC/sormr2.f(3) — go forth and multiply your matrices, you've got this 💜🦋