SORM2L(3)

💅 SORM2L(3) — Library Functions Manual 💅

🎀 NAME 🎀

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/sorm2l.f

✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

subroutine SORM2L (side, trans, m, n, k, a, lda, tau, c, ldc, work,
           info)

SORM2L multiplies a general matrix by the orthogonal matrix from a QL factorization determined by sgeqlf (unblocked algorithm).

🔥 Function/Subroutine Documentation 🔥

   subroutine SORM2L (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)

SORM2L multiplies a general matrix by the orthogonal matrix from a QL factorization determined by sgeqlf (unblocked algorithm). Periodt. 💅

🎯 Purpose 🎯

Ok so bestie, SORM2L 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(k) . . . H(2) H(1)

as returned by SGEQLF. Q is of order m if SIDE = 'L' and of order n if SIDE = 'R'. Slay. ✨

🌸 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 SGEQLF in the last 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 SGEQLF.
• 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 sorm2l.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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LAPACK, Version 3.12.0, source/date tag /home/abui...RC/sorm2l.f(3) — mwah, bestie, that’s the whole glow-up 💋✨🎀